I have a C7 Treefarmer grapple skidder 1983 I am having a problem with the torkconverter. This past week it blew the seal on the torkconverter filter canister. This has happened two other times in the last two years. I have changed the filter twice this year the torkconverter dosen't have a dip stick and the filler hole is in one H of a spot to even get any oil into it. Ive been putting 4/5 gallion back into it [ untill the skidder moves forward and reverse ] I have called Franklin but don't seem to talk to anyone that can give me how much fluid or what it might be. When it blows it is a super high pressure and before you realize whats happened the engine compartment ,radiator, tire on the filter side is drenched. Three to four gallion in a drop of a hat. Sure makes for a bad day , thanks for any ideas you may have. Bill
I'm just guessing as to the cause of your problem but here goes. I think your machine is a direct drive unit with converter, because my neighbor has a similar one. The converter oil system is probably just limited to the converter area, other than the oil cooler. Sounds like there is no reservoir and it's not connected to the hydraulic system. The converter housing should form the reservoir and have an oil level just below the bottom of the converter(maybe a level plug). Should be a charge pump picking up the oil in the sump and pumping it through the converter to keep it full, cool, and purged of air. I'm guessing the charge pressure is maybe 20-30 psi. This oil from the charge pump has got to be filtered and cooled first before it reaches the converter. It's probably a 'full flow' filter, and not getting bypassed oil. A partially plugged oil cooler, collapsing hydraulic hose(to or from the cooler or filter), or sticking relief valve(sets charge pressure), could make pressure at the filter, too high, even a spike will blow a filter. I would find a port at the filter housing and get a pressure reading. Leave the gauge there, so you can monitor. Also scan the numerous sites that offer service/operators manuals and you might find your info there. I would be concerned about a possible high oil level too, although I don't think that is your problem. If I see my friend, I will ask him how he sets his level and get back to you. Phil
Thanks so much for your reply Phil , your right about the converter housing being the oil tank, so it sounds like we are on the right track. I should finish my truck today so Monday I will pull it into the shop ,at least now I have a direction to go. I would of never dreamed that it had only 20/30 psi.When you talk about a oil cooler are you talking about the radiator area,not for sure but I don't think there's a cooler for this oil but for sure when I get all the iron tore off where a fellow can see better. Also do you have any idea ? Is the relief valve inside the housing or bolted somewhere on the housing ? On top off the housing there is some sort of valve and I believe it has four small 3/8 inch lines leaving from it. I tend to lean towards the relief valve,again I can't thank you enough ! Bill
I couldn't stand it so the truck waited and I tore off all the iron covers to see what was there. The relief valve sets on top of the torkconverter housing. One line 3/4 inch goes to one side of the filter then there is a smaller 1/2 inch that goes from the valve to the hydrostatic transmission. The other side of the filter,that hose is bigger and goes to the torkconverter it self. I believe you hit the nail on the head ! Once I get into it I will let you know whats going on,thanks again Bill PS there is no by pass on the filter housing its only the filter know other way to go.
Hydrostatic transmission? This is not the simple set-up that my friends C7 skidder has. If it's an automatic transmission you have, maybe an Allison? Got a picture? This is getting a little more complicated, I really recommend finding a service manual on the internet. The torque converter, whether sharing with the transmission or not must have a cooler somewhere, either in the radiator or plumbed into the engine cooling system, usually bolted to the side of it. A plugged cooler is rare, a plugged hydraulic hose is a bit more common and worth a check. Not all filters are the same either and it's possible to get the wrong one for that application. Phil
Phil it has a Clark transmission Model Number R28328-6 and the transmission dose have a cooler with the radiator. I have looked time and time again for a booklet but then again I don't know alot about computers or where to look. The hoses are a easy look and the check valve is also and as far as filters it is the same ones that I bought in 1996. This problem started in the fall of 2005 then again the winter of 2008 then last week again so it may go for a long time. I will start with everything you talked about.
I ran down to the shop it is called a Power Shift
See if there is a decal on the top of the converter. It would be good to have that info. It sounds like your converter is separate from your transmission, probably connected by a drive shaft. If your filter problem has stretched out over a few years, it's not as likely a hose or cooler problem. More likely a pressure setting, spiking pressure, or possibly oil type/viscosity, or the wrong filter. Too bad you were not posted in a more active part of the forum, to get better advice. The drive train you have is probably common to many types of machines(or skidders) and sometimes info is found by searching this way. It's quite possible the oil in your torque converter is shared with your transmission. If that were the case, you may have a scavenge pump near the bottom of the converter housing that returns oil to the transmission, and the transmission dipstick is used for oil level. The filter may be a transmission/torque filter, servicing both. Sometimes they mount these anywhere there is room. Try calling a few of these businesses, ask for a service manager, for advice, have your converter model and tranny # ready, it never hurts to ask. They don't know but what you are considering shipping the unit to them for repair. Ask for a service manual at the same time, for both units. These will have flow charts, pressure settings/check points, good for future reference and helps the resale value of the machine. Phil http://www.clark-transmissions.com/ http://www.pjpower.com/clark/?gclid=CIbC2MrB8Z4CFcNM5QodVXHwcQ http://www.associatedpowertrain.com/powertrain/converters/ http://www.bowerstransmission.com/clark_transmission.htm
Thanks again for all your help , at least I have some ideas on where to look. I will up date you with what I learn. Bill
I'd like to know a little more about this tranny setup. Is it seperate convertor and tranny connected by driveshaft? Is it a spin on filter or cannister filter? I'm certainly no expert on these things, but seems like an odd setup for convertor housing to be reservoir for tranny. I have worked on some clark trannys that have a slightly high filter pressure with a spin on filter. They would make aftermarket filters fail except for Donaldson filters. May be different from yours though. Also, your unit may have a pressue relief valve problem. But relief valves opening create more heat. Convertors and trannys create enough heat already, more heat from a relief is less than desirable. Instead, many setups like this use pressure regulating valves. They don't create the heat that relief valves do. Could have a broken spring in it creating excessive pressure Your going to have to get some tech info about your unit, like, what psi is the system supposed to be. Surely one of the links that Phil posted could provide some info on your unit.
The torkconverter and transmissiong is seperate,there is a drive shaft between them. The filter is a cannister type. I changed the oil in the torkconverter and it was pretty dirty meaning it was dark in color. But the transmission oil smells like transmission oil and is clear as the day I put it in there. So I believe there two seperate units . And the oil gets plenty hot in the converter there again I believe there is no oil raditor for it. The housing which looks like a bell housing bolted to the rear of the 4/53 is also the oil tank and the drive line comes out the center of it. What I can't figure out is how the two pumps operate with the torkconverter between them and the rear of the enigine. For sure it's a great learning exsperance and to some degree I enjoy wrenching on equipment.
If your convertor oil is dark and tranny oil is clear, they're two seperate reservoirs. The convertor oil is probably getting stained from a little leakage of motor oil from rear main seal. If this seperate torque convertor system does not have an oil cooler, that's a problem. Torque convertors generate more heat than trannys do anyday. When you change the filter, does it have the dark convertor oil in it? Not sure why your blowing your filter seal. Maybe a problem with pressure regulator. Another possiblity, you mentioned it had no cooler and oil gets plenty hot. And, you mentioned it takes some time to pass before seal blows. Hot oil will make o-rings and lathe cut rings (seal for you filter can) get hard as a brick bat. Hard seals cannot perform properly and they will fail in time. You also asked how the pumps work on the convertor housing. I assume you mean some kind of external pumps that are bolted to the rear of convertor housing, correct? That type of convertor has a ring gear on the rear of the convertor. Whenever the engine is running, the outer shell of the convertor is turning. The only part that "slips" is the output shaft of the convertor. That ring gear on rear of convertor is used to drive external pumps and shafts. BTW...welcome to the forum Autocar. :usa
Boy O Boy this is the greatest form sence apple pie ! I have learned more about this machine in the last few days then all the years I have owned it ! Can't thank everyone enough for there expotease. From my understanding this tractor was being built in Canada in 1983 then Franklin bought them and this skidder was moved half built to the satates. So everytime I went looking for parts and gave them the serical number they would run into a wall because Franklin used different parts that did't match what was on my tractor. I am not sure how the newer machines are built but this one is like a tank. Again thanks for all your in put. I am leaning towards a sticky valve,26 years old and as hot and dirty as that oil was thats a good place to start.
Well, that Phil is a pretty smart fellow. :yup Hi Phil! :waving Hope ya find your problem Autocar. We're all a little in the dark on your unit as we're not sure the way your system is set up or it's components. One thing I would do, though, when ya get it sorted out is install some kind of oil cooler on it. A torque convertor needs an oil cooler. Keep us updated on the repairs.
C7T Treefarmer Update Monday turned into a brutal day with 0 degree windchill and snow but I worked just outside of the shop. I took of the pressure relief valve and under it is a cone shape spring with a cap [rounded top ] and a 1 inch hole with a rubber seal that fits up into the valve bank. Not sure but will check tomarrow the bigger line 3/8 inch goes to the canister filter. A 1/4 or even smaller goes to the dash gages. Another small line 1/4 or smaller goes to the transmission. The valve bank it self ,the 3/8's and 1/4 inch go into the same cavity and so dose the one that goes up into the dash. The cone shape spring with the round cap seems just to push up and seal a hole in the valve bank. The open cavity where the three lines goes into there is a chrome 3/8inch rod that I figure has a plunger on it . Stumped on that but it measures around eight inches long with roll pins driven on the ends, [holding a coiled up spring ? ] After looking at some of the sites you told me about it looks like a Spicer C2000 torque converter. The only difference is where that drive line comes out on the lower left side theres a cover plate there on mine. If this dosen't make any sence to you tonight maybe after tomarrow I will trace the three lines out better but I have had enough for today I need to thaw out Now what I am about to tell you will get your gears turning ! I unscrewed the hydraulic fittings out of the valve bank to see inside it and in the threaded side of the 3/8 inch fitting there was a piece of yellow brass maybe 1/8 inch thick X1/4 inch X 3/8 inch . It was stuck and wouldn't make the turn in the 90 drgree turn. Possible that it may have flipped side ways now and then shutting off the flow ? For sure it was a restricked line like it was. Now where did the brass come from ? It seems like soft brass milled smooth on one side and eather a little rounded or chipped off something. Tomarrow I will trace the line out and see which direction it was trying to travel . Maybe that will give me a clue.
I'm sorry, I got sidetracked on my backhoe and haven't been back here to see how you made out. I see ATCOEQUIP has found you, good thing, I was going to PM him for help. He is pretty sharp on hydraulics and our forum expert, not bad with other problems too . Hard to say about the piece of brass, unless you posted a picture. Usually there is a screen in the oil pump pick-up, and the pump itself would grind up anything on the suction side. A schematic showing hydraulic flow for this torque converter would help determine where it came from. The line from the tranny may be a sensing line. The valve itself I will leave to ATCO to figure out, I'm not sure. The line to the dash is usually only for a transmission pressure or clutch pressure gauge. I can't imagine any other gauge from the converter needed, just a temp gauge.Phil
LMAO! Dang Canucks...they'll say anything about us Southern Hillbillies! Expert?...your the one who has a Tree Farmer named "Daisy", not me! :tong No, I'm no expert on these things, but all the details are still not here. Not sure, but you said you think it might be a C2000 converter. It should have an external charge pump. Haven't heard that mentioned. Maybe has an internal charge pump? It's possible. You mentioned in your other thread that a large 3/4 line goes from converter housing to one side of filter. That may be the feed to the filter from charge pump. Then the 3/8 hose goes from filter to pressure regulator, the valve body you removed. Then you have 2 other lines connected to that port chamber on the regulator; 1/4 line going to dash (pressure gauge maybe?), and 1/4 line going to tranny. I ain't figured out the line going to tranny since we've already determined it uses it's own oil reservoir. As for the brass piece, if the oil flows the way I described, and it's lodged in the 3/8 line fitting of line coming from filter, then you may have found the cause of filter seal failure. The restriction is happening before oil/pressure gets to pressure regulator. Where did the brass come from? Good question, how did it get past the filter? Unless the filter has a by-pass valve in it. If all this is correct, the piece of brass could be from a wear end plate of charge pump. That's about all the noodling I can think of without more knowledge of the unit. I still can't believe it doesn't use an oil cooler myself.
From my experience, tree farmer did not spend any money on items that were not really needed. As most of their market was northern Canada (cold!!!!!!), an oil cooler would fit that view.
Day Two C7T Treefarmer Update Here we go I traced the lines and put everything back togather today. 3/8 line goes from pressure releif valve to transmission [ On a block that has all the lines for forward1,2,3 and reverce ] 1/8 line goes from preasure releif valve to a [ Drive Oil Gage on dash ]pressure run around 245 the gage goes to 300 if I remenber rightly.Looking at the filter canister the 1/2 inch line on the left side goes to the pressure releif valve.The right side 1/2 inch goes to the right side of a gear pump on the lower back edge of the torkconverter housing. Here's where it gets crazy, the left side of the gear pump goes to the right side of the transmission. Then on the lower left corner of the torkconverter housing there is a 3/4 inch line that goes half way back on the bottom of the transmission. On the lower right side of the torkconverter housing there is a 3/4 inch line running all the way on the right side of the tractor and hookes into a 6X12 box ? with the water pump and two 2 1/2 inch water lines hooking into it. It also where the line hooks on to says [ From Filter ] Then leaving the Box ? says [ To Filter ] 3/4 inch goes to right side of transmission with a T connection at T steel line goes to the rear of the trasmissiom and goes into the top right where the winch drive line comes through. The 3/4 line just goes into the right front edge of the trasmission. Not sure but is the transmission water cooled at the square box ? Is it possible that the transmission has a seperation in it and keeps the two oils from blending ? I would just about bet there's separate oil in the two ! I bleed the air if there was any in the dead end lines and then drove it around for a while.I am more confused now then ever the way it is put togather I am not to sure that it won,t shot off to the moon I called the numbers you guys gave me to find out how much fuild the converter held , the guy said I would have to call Detroit motor division ointhead Beats me ! So I called Ricker Equipment and asked them and they called me back and said they would take a shot at it and say 5 or 6 gallion ointhead With answers like they gave me I wonder where our country will be in another twenty years. But then thats another story !
The one number I called carryed Spicer Torkconverters and I am pretty sure that it is a C2000, this was where the fellow told me to call Detroit moter division Right and left is when your seating in the drivers seat. except the filter where your standing on the side of the tractor looking at it.
Ok, I'll take a stab at this. Sounds like the tranny and converter share oil. Here's my thoughts of how it works. Suction line on side of tranny goes to left side of pump on rear of coverter, that's what we call a "charge pump". The converter doesn't have the ability to draw oil to itself, it has to have oil fed to it under pressure. Oil leaves the charge pump, line on right side of pump, and goes to filter. Oil leaves filter and goes to pressure regulating valve mounted on coverter housing. Two other lines are connected to this chamber on the valve that shares the oil coming from filter. One line goes to pressure gauge on dash to monitor system pressure, the other line goes to transmission control valve to provide pressurised oil to engage fwd and rev clutch packs. Pressure is developed by the spring and cap you described going into the bottom of the 1" port of the pressure regulating valve when you removed valve. Once enough pressure is developed by charge pump, it overcomes the pressure of the spring and it unseats the "cap" or "piston". This also serves as a back flow valve for the conveter. Oil then flows through this port to feed converter via internal piping. Once it's done it's work inside the converter, the oil comes out of converter and goes, via internal piping, to fitting on lower right of coverter housing. Heated oil from coverter goes to engine coolant heat exchanger, then leaves heat exchanger and goes back to sump of transmission to start the flow cycle over again. The 3/4 line on lower left corner of convertor housing and goes back to bottom of tranny is a drain line to drain internal leakage of oil from convertor back to tranny. That's pretty much the way I read it. One question I have, when you removed the pressure regulating valve, you mentioned the 1" port that the spring and piston goes into. Is there another port or hole on the bottom of the valve beside the one you mentioned?
Yes there is another hole about centered thats a inch , plus a hole about the size of a 22 caliber casing. You guys amaze me ! Thanks for all the info,I believe I am going to try and suck all the oil out of the converter housing . Change the filter again and then run it again on my next job and see how things work out. Thanks again for all the help Bill
Ahhh, that's what I thought. Then I must ammend my previous post. Pressure is developed using two things; 1) the piston and spring assy you described previously. Once sufficient pressure is achieved it unseats the piston and allows oil to flow to converter. It also serves as a backflow preventer when converter is under load. And 2) by the spool/spring assembly inside the valve body. You described it previously as a chrome rod with a spring on one end. This is the pressure regulating spool. The charge pump can deliver more oil than is needed by the converter. Pressure is developed by the resistance of the spring under the valve body. Any excessive oil/pressure shifts the pressure regulating spool and allows oil to escape through the other 1" hole in the bottom of the valve body. This oil drains back into the sump of the converter housing. The 22 cal size hole is probably a vent for the spring side of the spool preventing spool leakage oil from getting trapped in the spring chamber and affecting spool movement. The movement of this spool is what maintains a uniform pressure on the system. As dumped oil fills the coverter housing, it drains back to the transmission sump via hose on lower left of converter housing. Therefore, you shouldn't have to "add oil" to the converter housing. Oil level is maintained at the transmission.
I just can't get that into my head ! I still think there is no oil mixing between the transmission and the torkconverter. I pressured wash the engine and engine compartment and left it run for a hour and the transmission level was a little low . What your saying is when the transmission level is full the torkconverter will be also ? Just don't understand that .
Keep in mind I do not know your setup. I'm just working through the typical logic of what oil does in these units given the connections/hoses you describe. Oil in the torque converter: Within the housing of the torque converter, the converter, itself, requires no oil within the housing. It only needs oil flowing through the inside of the converter, through the internal turbines to do it's work. Then it flows back out of coverter to wherever, to be delivered through converter again. It requires a constant flow of oil through the inside of the converter. Oustide the converter body, within the converter housing, it requires no oil. But the bearings and gears that drive the charge pump and converter output shaft require lubrication. You don't need a housing full of oil to achieve that, just enough in the sump of converter housing to lube parts is all that is required. Excess oil will flow out of pressure regulating valve and fill converter housing sump. The sump will fill until the oil reaches the level of that fitting on lower left of converter housing with the 3/4 hose attached to it. That hose returns sump oil back to tranny sump. That "sump drain" fitting maintains a specific level of oil in the converter housing sump. Just like an overflow pipe does in a fishing pond. The converter housing oil level maintains itself. All you have to maintain is the level in the tranny.
Ok if I understand what your saying, if my transmission level says full then the torkconverter is ok ? If thats the case where did the four gallions go that I poured in the hole that is on the side of the torkeconverter ? It makes some sence because it was a H of a job to get to the plug let alone pour oil into it. Just by chance do you have any idea where a guy could find a operater's manual for one ? Thanks again for all your help. After thinking about what you have told me probably three years ago I over filled the dang thing thinking that it need oil.
Do you have the make and model of the transmission or the info on any tags on the torque converter. As I recall back when those were built you could get any of three different transmission. Clark, Twin Disc and Allison, newer machines might have had a Funk transmission. The Clark and Twin Disc transmissions were mounted seperate from the torque converter. Even though the torque was seperate it still received the operating oil from the transmission. In the Allison the torque converter was inside the transmission case. I think AtcoEquip is pretty accurate in his explanation of what it sounds like you have. A photo would help a lot. As I recall all those units had two 1/8" pipe plugs on the side of the main case of the transmission. You checked the oil with the engine running in neutral at low idle. Oil should come out of the lower plug and not out of the upper plug when the lever is correct. As I recall the Allisons always had a dipstick. Does your transmission have a dipstick? Are you checking the level with the engine running or shut down? Granted four gallons is a lot of oil in those units, but you might have just overfilled the unit and been able to run till now not knowing any difference.
Yes the transmission dose have a dip stick. It is a Clark Model R28328-6 and yes I check the oil in it after it warms up while it idles. Atcoequip tells me that [ This is how I think he tells me ] that the oil is shared ,but the very first time I had a problm with it the oil was very dark and the transmission oil is as clear as if I poured it in yesturday. But tracing lines Atcoquip translation is right but like I told him I just can't get it though my head with the oil being so different in colors. Frustrating but at the same time I get a kick trying to figure it out. I agree a picture is worth a thousand words but I can never figure out how to that eather. Happy New Year !
Ahh, finally got some help from John C. Seems my buddy Phil has left me here all alone. :falldownlaugh Hi Phil. :waving Hey John, he thinks the coverter is a C2000 Clark. Here's a PDF of one. http://www.dana.com/offhighway_systems/products/C2000 Torque Converter Spec.pdf Hey Autocar, you got pics on your computer and just don't know how to post them here?
No pictures on the computer can't seem to get them any farther then Photo Bucket. com. My wife is the computer whise in our family and she is stumped also on the picture transfer.
Whoa, slow down dude. If you have pics, whether from digital camera of cell phone camera, download them to your computer, in "My Documents" or "My Pictures". Once you have them saved in your computer, you can upload them to the forum on one of your posts. Like this
ATCOEQUIP, In think you solved the issue with that brochure. It says the converter housing is dry. Apparently there wasn't supposed to be any oil in the converter housing at all. Autocar, now you need to find a way to drain the oil out of that housing.
I saw that in the housing mounting spec John, SAE 3 (dry). Not sure what that means. I'm just thinking there has to be some oil in there to lubricate the drive gear and bearings for the charge pump drive. I could be wrong for sure, but every converter I've worked on that has pumps driving from the rear gear on converter body requires some lube for gears and bearings.
More confused then ever now, this coming week I will call Baker Equipment and see if they have a on road repair man . Then have him come over here for a day and fill my ear . Well worth what it cost to fine out what going on. I believe they are the Franklin dealer in Ohio. Will let everyone know what I fine out. Bill
JAN. 14 Treefarmer Update Got some time today and drained the transmission fluid. I also found a five inch by two inch screen in the transmission that was about plugged [ looked like to me it was a hard carbon deposit over it ] if that makes any sence. Then I found a tag telling what kind of oil to use, here to find out I was putting the wrong kind in. I was using John Deer hydraulic oil and it called for Type A or C3 transmission fluid. Tomarrow I will cut the filter apart and see what it looks like inside. I was feeling pretty good till all the fluid drained out and I ran a magnet back on the floor of the transmission. I pulled out two pins that are a 1/4 inch by 1 3/4 inch. No wear marks, smooth as silk. They are magnitize not alot but you can fell it when you pull them apart or flip them end for end and they repell each other. I called the dealer to question the filter number and again they told me they couldn't help me because the tractor was built in Canada dosen't make alot of sence to me. Any thoughts from anyone as far as where the pins may have come from ?
What type of tractor is it? Also, please post pictures of the cut filter when you can. We may be able to help isolate the source...
It is a C7T Treefarmer Grapple Skidder with a 4/53 turbo and a clark power shift transmission. And forget the pictures I have never conquered that end of a computer yet !
Have no idea what the two pins are. I thought you were having someone come out and look the tranny and torque converter over?
Please keep all posts regarding this machine within this thread. It will make it easier for those helping you to follow the progress in one read. Thank you.
The two pins could simply be magnets that will attract any steel shavings that the transmission could produce. I have seen this alot in trannies. Most of the time there is some sort of indent on the bottom of the pan for the magnet to seat in but not always. They could just be free floating. The other thing is that the transmission fluid will be much thinner than the hydraulic oil, as well as have more lubricating properties to it. This could cause the transmission to run at much higher pressures than it was intended to do. I think you really should drain the entire system, replace that transmission filter and then refill to the correct fluid level. Hopefully you will be able to find the correct fluid specifications for it.
I cut the filter open this afternoon and the paper was a light brown but there wasn't anything, small particals or any other debris. This filter was installed November of 2008. I am starting to lean towards a pressure releif valve that sticks now and then. Probably crazy thinking on my part but I am wondering about installing a pre-set pressure relief valve and installing it on the [ in ] and [out ] side of the filter line . So when the pressure hits 300 it opens and blows into a portable tank that I can put in the belly pan. Probably by now half you guys are shacking your heards When it only happens once a year or so its a hard problem to solve, at least for me. The mess it makes in a split second is unbeliveable,I always load or unload on the road and I can just see it blowing when a car comes along side or covering the road with oil. I did talk to the Franklin dealed last week about having someone coming over and just pick his brain for a few hours. They get $68.00 a hour and there three and half hours east of me I can't afford five hundred dollars travel time right now. It has warmed up enough that it is to soft to work so I am pulling the sheet metal off it and having the guy come and put new injectors and set the rack , life is good !
Just a quick story on the C270 Clark torque converter and trans. The small alum pump on the converter is the charge pump. It feeds from the transmission case to the clutch pressure regulater valve on the converter which in turn first feeds The tranmission control valve. When the proper clutch pressure is attained, the clutch pressure regulater valve shifts and starts to dump oil into the torque converter. The poppit under the clutch pressure regulater valve is a safety valve for the converter. If there is a blockage down steam from the converter and the internal pressure gets above 70 PSI the poppit opens and dumps the oil into the converter and out through the bottom drain line which goes back to the transmission case. There is lube oil fed through orfices to lube the bearings in the converter, this oil also goes into the case and drains back to the transmission. If the drain line back to the transmission gets plugged, oil will build up in the converter case and blow out the breather and or lower the oil level in the trans. case to the point that the charge pump starts to starve for oil and can't maintain clutch pressure, at that point the Clutch pressure regulater valve will close off the converter . The same thing can happen if the oil cooler or the lines to and from it get plugged. (I have seen the inside lining of the hoses break loose under flow and plug the line. when you pull the hose, it will look OK). The way to check this is to measure pressure at the port on the clutch pressure regulating valve, this is "Converter in pressure". with hot oil at 2000 rpm in neutral the pressure should read 40-80 PSI. If the poppit safety valve is leaking or stuck open too much oil will dump into the converter case and since the drain is just gravity feed too much oil will build up in the case, all this oil is not getting to the cooler so it just gets hotter as it recirculates. To check the cooler for restriction measure pressure in and pressure out In pressure should be 25-60 PSI at 2000 RPM with oil temp at least 180 F. The out pressure should be 5-10 PSI. THESE PRESSURES ARE FOR A CLARK SKIDDER WITH THE SAME CONVERTER AND TRANMISSION. They may be a little different on the C7.
Oldseabee thanks for your information, every time someone tells something about it I pick up more understanding knowledge. Your talking about a hydraulic gage arn't you to check the pressure. The pressures you talk about seems low to me can you tell me what the one is for on the dash,it reads around 249 when the machine is running and dosen't change when your in gear and moving.
I would check the type of oil you have in the convertor may need diffrent brand or grade also check that your hoses have not decided to seperate in side causing them to block as thwe pressure rises
The 249 PSI pressure is clutch pressure inside the transmission clutch drums which is controled by the valve on the converter, that is why the small hose goes from the guage in the dash to the clutch pressure regulater valve on the converter housing. The pressures I mentioned are internal pressures inside the converter members which are limited by the poppit and spring under the control valve and are caused by restriction of flow through the converter, line to the oil cooler, the oil cooler itself, and the line back to the transmission case where the oil resevoir is located. The hard part to get your head around is the fact that the transmission and converter are seperate physically but are interconnected hydraulically.
Another thing that I forgot to mention is that the breather on the converter housing is really a one way check valve, lets air in but should not let oil splash out. These have a history of losing the poppit and the result is oil all over the place.
Thanks for all the info Oldseabee I have been trucking logs for the last two weeks and waiting on it to warm up, before the mechanic will finish the work on my 4/53 . You have gave me alot of things to check out thanks again