D7H, 79Z 1753. Problem has been ongoing since I bought the tractor about 2 years ago. The problem has stayed very steady and persistent. On a cool day the trans will heat up to 210 with the motor running 170. It heats up slowly taking an hour or so if pushing hard, in less than 2 hours it heats up if working easy. It slowly gets to 220-230 on 80-90 degree days bringing the motor up to 180's. In 90-100 degree days it's a problem with it getting 230's. The trans won't cool done with the tractor sitting still, med throttle or low throttle. It might cool off 10 degrees or so but never cools to the motor temp. Things I've done: The injector pump was remaned by cat when I first got the dozer. Last year I took off the trans cooler and cleaned it, some blockage. Pump preasure was like 20 psi low-put a cat reman on. Checked temps gauge with a temp gun. This winter I had the torque rebuilt, all new hoses on the tranny and torque, new radiator, cleaned the tranny cooler-no blockage. No change. Did more preasure checks. Everything checked out ok except the pump drive lubrication. This port is on the front of flywheel housing, same side as trans cooler. it checked 30psi low idle (40psi +- 10) 45 psi high idle (70 +- 10 is the spec). Anyone have ideas? Also changed filter and oil, checked screens which are clean. Old oil smelled burnt. Trans holds, shifts just like it should. Brakes and steering clutches are excellent. Tractor will coast on a slope.
I followed this problem in previous threads, looking forward to hearing suggestions Ken
Found the Previous thread Preasure checks with hot oil Priority valve 415 (420 +- 20) Transmission lubrication 31 (31 +- 5) Converter inlet preasure low idle 50 (80 +-15) high idle 90 (100 +-10) Converter outlet preasure 50 (60 +- 10) And the Pump drive lubrication low idle 30 (40 +- 10) high idle 45 (70 +-10)
valve body?
have you replaced the trans and torque scavenge pumps? I would much rather have put on a new cooler core. If these are all good and it still builds heat that leaves the transmission.
The scavanger pump is part of the transmission pump that has 3 sections. I replaced the radiator because 2 sections were leaking, put in all 8 new and kept the old ones for spares. Also new tracks, a final drive rebuilt that only had mud holding the oil in, all new trans and hydraulic hoses, cat rebuilt all the cylinders, and I attempted paint. Used a heat sensor today to check the temps like suggested in the first thread. I couldn't find much variance in the water temp at the trans cooler 170 167. The trans lines going in and out of trans cooler were 190 168 The gauge was reading 210. I'm pretty sure the gauge is right. On hot days the trans heats up, then the hydraulic slowly climps to within 5 or 10 degrees. the trans gets to 240 or so, the hyd slowly comes up to 230 and the hyd alarm goes off. Is this a possibility that the pump drive lubrication is dumping way to much oil into the converter housing? I haven't dived into the clutch and brake valve body or the transmission valve body.
I chased something similar when I was a boy and after a day testing I popped the little cover off the back that has the P1 and P2 Pressure Nipples and they both had damaged O-rings on the jumper tubes to the Valve Pack.....
I don't what kind of temp sensors you but you should be able to pull and test with a known heat source and verifier the gauge reading if they are thermsister type and can find the milivolt range use a multimeter in line and check milivolt output Heat guns are great but can be way off. I'm sure that you know that using the heat gun the area must be clean and has a dull non-reflecting surface
Them transmission pumps are bad about causing this problem. With all the work you have already done it would not hurt to pull it and tear down for inspection. What happens is this Direct Displacement pump is good enough to supply good pressure for brakes..then transmission...then the it starts to get a little weaker onve it finally gets to Lube. The pressures are set with relief valves....even though the pump can show to have good pressure...this does not mean it has the VOLUME to supply everything the proper amount of oil that each system requires. So when the pump is showing good pressures in several places everyone overlooks it but in reality an internally scratched pump could still supply good pressure to the places it has priority but not move enough oil to supply everything with a sufficient amount of oil...ecspecially in convertor and what is left to go to the cooler. My next suggestion is to stay away from aftermarket pumps. They are over 1K cheaper and sound like a good deal. I have never found 2 from any place that EVER held up any amount of time. Some people buy the new aftermarket pump, tear them down and swap the bushings to neew Federal Mogal bushings and claim they are a little better but i found buying the good high dollar pump from Cat to be the best bet.
Check the priority pressure at high and low idle with hot oil as you shift through all gears and pull and release the steering levers. Then put the park brake on. Record all presures and post them here. Later Bob
pls check the brakes are 100per released before moving dozer,binding brakes can generate heat and rise tc temp too.in very lowidle with second gear dozer has to overcome its inertia
87 degrees here on tuesday, under 40 and rain today. But went out and warmed dozer up, 3rd gear 1/3 throttle 20 minutes or so got the torque up to 160-180 range, then took more pressure tests. Pump pressure at the filter housing 400 psi low idle (390 spec) 470 high idle (475 +-25) Left clutch 300 (335 +-25) clutch pulled 0 (less than 10 psi) Right clutch 300 (335 +-25) clutch pulled 0 (less than 10 psi) Left brake 390 (410 +- 20) brake on 30 (less than 10) Right brake 390 (410 +- 20) brake on 25 ( less than 10) The brake pressures off are my doing. I adjusted the steering and break control valve - the dozer would yank your socks off turning. When the clutch was pulled there was no clutch release then braking, when the clutch released the brake would be on already. Made it hard to make smooth turns. The clutches will release now without the brakes dragging. Haven't had the brakes be weak at all when turning. Bob/Ont checked priority valve like you suggested. Burried the blade in but tracks would spin at high idle, the rain and sleet didn't help. so ended up at about 1/3 throttle going through the gears, no clutching, right then left clutch in each gear, right then left clutch and brake each gear. The readings were pretty consistant at 405 410. In gear 410, clutch activated 405, clutch and brake activated 410. neutral with Park Brake on 415 In neutral low idle 395 (no spec) high idle 455 (420 +- 20) I got a reading in 3rd gear at high idle 435, clutch activated 425, and about then it started spinning the left track, so backed off throttle.
Cat 385 I'll try the 2nd gear low idle when I get to run after the rain. I do have the dozer where if I'm backing down a slope and pull a clutch that side will free-wheel ahead of the other side.
Looks like you don't have an oil flow leakage problem. Are you pushing hard in second instead of first gear? Those H tractors have things cut to the bone as far as oil flow goes. Not like the old days with a 40 gpm pump circulating oil. Later Bob
Bob/Ont - 1st gear pushing, back up 2nd half throttle. I run steady and push a load and on a 100 degree day I could understand if it wants to heat up some. Seem's it ought to cool down if I just let it run with no load at 1/4 throttle. It doesn't. Thanks for your help, this rules out oil flow problems in the steering and brake valves, and the transmission? JeremiahSr - replaced the transmission pump fall of 2011 with a cat reman and it made no difference.
Have you checked your fan speed at hi and lo idle, im guessing it will be a hydraulic fan , could be getting sluggish
As far as fan goes how are the pulleys how bad are they wore? Have you had to change out the belts lately because they are coming apart at the top side from setting to deep down in the pulleys.If so pulleys need replaced or regroved. Friend of mine had a D6R this summer running hot,they changed out the sizing on one of the pulley and it speed up the fan ,and he said it really cooled the machine down.I don't know what pulley they changed,but sounded like it is working. I have a older D6R that runs hotter then i like,but have it cools down as soon as you stop for just a little while.Will be working on it here this summer.Will be looking at changing out pulley size if things are still working good for my friends R. Are you running engine in closers? In grass and clearing trees stuff will suck in from the back of the machine and get into the radaitor.Might try inclosing the back,underfuel tank.If your running ripper might have to make something,but cat has a guard for below the fuel tank.Two machine of mine has them and help to keep a lot of the trash out ,which comes off the rear track area. Keep us posted.Good luck
I thought on the H's the trans cooler is mounted to the engine and cooled by engine coolant. If the engine is not heating up the cooler could be at fault. Also if I remember correctly there is a thermo valve on the trans oil to bypass the cooler when cold. I may be way off base here as it has been a few years since I worked on an H model.
Mjrdude1 - The transmission cooler is on the left side of engine and cooled by engine coolant. This clutch steer machine does not have a hydraulic cooler mounted by the fan, the differential steer ones do. Construct'O - The pulleys are good, belts newish and tight. I do have inclosures. The transmission heats up regardless. Fall of 2011 I was packing silage and the stupid transmission wanted to heat up. I'd clean out ther radiator well, the motor would be running around 180 and the trans would heat on up. And for some reason, I assume it's because the hydraulic pump is picking up the heat from the flywheel housing, the hydraulic temp would slowly follow. Pushing some dirt on the next job and the motor is fine, hydraulic fine, transmission slowly gets hotter as the day goes on. It was hot, but I was babying it. Eventually the trans climbs to 240, the motor is running 200 ish, and the hydraulics hit 230 and the alarm goes off. This was daily and has stayed consistent. The transmission cooler is clean. The transmission pump replaced with a reman cat, new hoses, new filter, magnets are clean, and rebuilt the torque convertor. I haven't had the alarm going off yet, but it's behaving just exactly the same. I avoided building new ponds with it in the heat last summer, but that's not going to be an option this summer. Basically I limped it through last summer. I think it is a flow problem with the pump lubrication and oil cooler. (I thought it was the torque convertor and was wrong there though - :Banghead ) The fact the pump lubrication is low makes me wonder if somehow oil is dumping into the flywheel housing flooding the convertor making it hot, and letting the oil that should be going through the cooler bypass the cooler. Would taking a catch pan and see how much oil is coming out of the convertor be something to try? Or is it way more than what I could catch? Would taking a flow meter test on the oil cooler or line coming to the convertor be the thing? I'm not equipped for that though. Quite a ways out from a service truck so that would be kind of pricey.
Sounds like you have done alot of the right things ,but isn't working.Engine and convertor temp run hand in hand.Engine heats then trans temp comes up.Trans heats engine temp comes up.The way your describing things the trans temp is the first to come up,so i'm guessing the engine isn't the start of things in your case. Had a go around with my D6H,different problem,got it fix post on here 9 pages ,but finally got it solved. My 6H the convertor has always run right up there ever since it was new. 210 degrees by the gage.It got to running hotter after it was rebuild.2500 hours later the main bearing and seal went out and filled the housing up with so much oil that it was running out around the starter.New one here on me. Pulled the convertor and the front seal blew because of bad bearing.Talk to Cat and told them old bearing made it to 15,000 + hours and rebuild couldn't make it 2500 hours.So they redid it and too there credit helped out on the cost.After this rebuild it has run cooler then ever. Couldn't hurt to try draining the convertor and see how much oil you get.Shouldn't be over a couple gallon from other post on here.On the R there is a return screen at the transmission pump, have you checked it out,not sure on the H.It is the line coing from the trans pump to the convertor there is a small scren there also fits in the hose or convertor,by the parts book 3t6471.My helpers just did this last week because one of the C clamps on the hose was broke and seeping oil where the screen sets. Think there is a tube coming down from the trans pump where there a screen also.They didn't lose much oil.Screen should be clean.Have you checked the one in the rear of the transmission.Your lose oil there ,but you can get it out and back in if you have help and hurrrrrry!!!!!! My machines are all diff steer.What about hydraulic filters.have a spin on one behind the trans filter on diff steer.Have you check trans filter by cutting it apart.Last time trans oil changed.Probably did that when you did covertor,but wouldn't have had too,unless needed. If it was the engine first the is a oil cooler on the left side that has coolent running through it that over the years get plugged the doesn't cool the engine oil and the heat in the engine temp will be the first to come up the the trans start creeping up,but sounds like your having the opposite problem. Keep checking things out, and posting here.Has the engine had the fuel turn up much? Long post just thought of something else.You mention adjust the steering clutch and brak likage.Are you sure you have thing adjusted correctly.If the brakes are set right and dragging just so much the slights that would build up heat.Might not hurt to start check thing the if your sure all the other thing are in place.Brakes ,steering clutch working right, check there!!!!!!!!
Check brake and steering clutches Sorry about the long post above,but after thinking about you adjusted your steering clutch and brake linkage.That that may be your problem,or has been all along. I would search there for you next clues if it was me and the above stuff checks out.If brakes would be dragging just a little it could be building up heat.Last time brakes and steering clucth have been worked on?????? Reread your post, you said oil smelled burnt are you sure your brakes and steering clutch bands aren't coming apart even thou they seem to be working okay.Also the bands in the trans.Has the trans ever been out,how many hours????? They aren't that hard to pull.Two hours and it can be out. Good luck
I would still want to see inside that pump my good man.
Kent, have you checked the torque inlet and outlet pressures while stalling the torque. Should get 115 PSI inlet and 60 PSI outlet. If the inlet drops below the outlet I know what is the problem. Later Bob
Bob The inlet drops to 80, outlet is 60, with torque stalled, full throttle, third gear. Didn't have a helper so buried the blade in the ground to hold it rather than using the brake. core It has a belt driven fan.
Construct'O Cat records show a trans rebuild 6000 hrs ago. I do not know if clutches and brakes were done. I have checked three screens, the one in torque, the one in the front with the magnet and the back one. It has the one canister type trans filter, cut into it and didn't find any shiny or notice any foreign material. Took cooler off, was 90% clean, couple tubes had some silicone (someone before had put silicone on radiator at some point) blockage. Was very clean when put back on. Fuel is not turned up. Remaned injector pump set to specs about 3000 hrs ago.
With the converter stalled does the driveshaft creap at all ?
Will sounds like you done a lot of the possibles.Hopefully Bob will have the answer!!!!!! The bad part about things are that reman or rebuild have issues from not being done right sometimes.If all the filter show clean you would think things are up to suff! Have you every done ay oil samples?Might try that. Also what type & weight of oil are you running in the trans .I use to run always 30weight engine oil,but changed over to the new Cat trans oil ,they say it is better for the plates. My D6H has over 18,000 on trans(15k hours with the 30W) and has never been touched.I bought the machine new 1988 it still is strong,but planning on rebuilding it this summer.Keep looking and repost.Sorry no help here. Just one other thing,hows the shift cable, the one for forward and revesre.Is it all the way in and out of the two gears.Might be not getting moved all the way in gear locking them all the way in.Well good luck
shopguy - I didn't notice driveshaft turning at all, the shield is in place so didn't see it clearly. Will check it better next time. Construct'O - Haven't done any samples - thats a thought. After I finish the pond I'm on it'll have 70 hrs or more on the oil change. I use Universal TO 30 in the trans and they will do oil test for me, I have the sample bottles. I think the shift cable is correct, replaced both when got the tractor because they were stiff. Thanks for the help, it's a bit of a head banger. JeremiahSr - I have learned that sometimes I should listen to people.
Those pressures are good for a sound converter. I had a converter once that had 60 at the outlet and 0 at the inlet if you can imagine that. It had an iron sealing ring missing and under load the Vortex flow of the converter was pulling the oil away from the inlet faster than the pump could supply it and blowing the oil out by the missing ring. You don't have that problem. Later Bob
as to the oil cooler.. when you say it was 90% clean are you talking about the large round openings top and bottom? this is not where your problem will be, that would be where the oil goes and you cannot see in there. Mine was 100% clean in the coolant side and bad serious clogged where the oil must flow (and transfer heat). This cannot be viewed unless you rip out the copper straws. I would bet on the plugged cooler, and a junk pump which filled it. I hope you backed off the brakes just once while hot to see if this was adding to your issues.
Kent, Just to make sure of one thing. The priority pressure? what happened at low idle with warm oil when you flipped the brake /trans lockout lever up and down? Later Bob
the torque converter outlet if it iws 100 psi like I saw in the thread here. It is way too high and would indicate leakage in the torque converter. it would have to be rebuilt
oldirt - can't back off the brakes, oil preasure releases them. r20d12 - The highest convertor outlet preasure I have recorded was 60 psi. Bob - The priority preasure stays the same. Tried some things Replaced the trans cooler with a cat reman - no difference. Convinced it's a flow problem through the cooler so took off convertor outlet relief valve. It looked right, a few scratches on the spool. It takes preasure to override the springs and let oil to the cooler---so I took out one of the 2 springs and the shims. This did make a bit of difference, as it runs just a touch cooler. Interestingly the convertor outlet preasure was still 60 psi. I also took off and checked the blocks that the convertor inlet and the cooler outlet hoses hook too on the transmission. In the block that hooks to the convertor inlet hose there is the orifice and outlet to the pump drive lubrication hose. So if the transmission pump drive lubrication preasure is low this would indicate low flow and preasure to the convertor inlet hose. My sherlocky deduction is this; convertor inlet preasure is good out of priority valve at the preasure port on back of trans. convertor inlet preasure and/or flow is not good coming out of trans to the convertor inlet hose. problem is in the transmission, or possibly pump flow. Have been working on the dozer away from home, hope to finish that pond and get it home to have a look inside that trans this week. If my heating up had not been so consistant or changed at all when I put the cat remaned pump on I would take the pump off first.
I did a flow meter test today: Convertor inlet, high idle, stalled 28 gpm Convertor outlet checked on the return line after the oil cooler, high idle, stalled 24 gpm Would this seem right or is the convertor loosing to much oil? Same test in neutral: inlet 32 gpm, outlet 30 gpm The transmission pump output spec is 36 gpm
That doesn't sound bad Kent. A cat converter normally looses about 2 or3 GPM at stall. You are getting reasonable flow and that's what keeps the trans cool. Later Bob
Check suction line for either air leak or a plugged screen.
1st - In the post where I took the springs out of the priority valve and got 60 psi outlet it was because I didn't have the tractor in gear stalled. I did take the trans and differential out and looked at it, all the tubing in the case was good, clutch discs we could see and everything else looked good. Today I took out the convertor and took it apart. The clearance between the stator and the turbine is .065 in. and max is .030 in. The clearance between the stator and the impeller is loose too. Going parts shopping tomorrow.
This is Kent "not the mechanic" reporting; The clearance measurement between the stator and turbine on my parts were almost exactly the same as on brand new cat parts. This is Kent "And the puzzle wins again:Banghead" signing off.
Check changing too different size pulley as posted earlier if you can find anything,look into this option at least.Good luck
The trans lines going in and out of trans cooler were 190 168 The gauge was reading 210. Cat spec on cooler performance is 8C-22C (46.4F-71.6F) meaning this is the range that you should see if the cooler is efficient. If you are not in this range and too low it means you have an issue with the coolant taking the heat away. From your numbers 190-168 you are transfering 22 degrees F-not enough. You have a water flow problem. I would be going after the engine water pump. I can't see in any of the posts where you have replaced the water pump? All the oil pressures-P (pump) P1 (speed clutch)-P2 (direction clutch)-P3 (TC Inlet)-P4 (TC outlet)-P5 (lube) are very close. I really don't think its an oil flow problem. I think you have a water pump flow problem from the engine water pump. Hope this helps! Z
Kent, any progress?
Kent have you found the cause yet :dizzy
I have not found the cause yet. New water pump, no change. Replaced the torque convertor with a reman from american crane and tractor, put my case on it, no change. Probably won't do anymore for a while.
Kent i just got done working on my D6R for heating and this is what we did and some of the issues.First the main crankshaft seal was leaking oil,just enough to collect dust and dirt.The pulleys was caked with the dryed oil,and the belts had to be slipping some by the looks of things. I had replaced 4 of my 7 cores with cores that they used in landfill machines,earlier(they was seeping)had the other three cleaned and rodded.So decided to replace the other three this time just for the heating.I think the oil seal was causing the most problem,but while we were ther did all this other stuff . Then we took a fan pulley(top pulley) off a D6H which is smaller then on the D6R's.We just did the top one,but if you do the top and bottom one it will almost sound like a plane.One guy did both ,but my worry with both is the stress on the fan blade bearings.Replaced all new. So not sure if it would work for you ,but if you could find out if a D6R pulley would work on you shaft on your D7H maybe that would help.Might not even be possible between the D7H and the D6R pulleys ,but some thing to check out. Everyone he has done guys are saying it works.The guy with the two pulley change says no way he can make it heat.I will be trying mine out the next day or two here so will report back.Report back on a couple other machine are also coming back positive.Good luck
Need to know ALL spec's and Temps BEFORE you can DIAGNOIS problem IF one is present.. One thing you need to know is that the torq converter ALLWAYS will run hotter that the engine water temp! And to cool the torq con. temp you CAN NOT let it idle, you want too run at high idle and then get a reading! At idle and low rpms you have not enough flow (air and fluid) to cool. You need to get a base reading and get ALL your base temps, ect. in order to diagnose the problem, if you even have a problem? Does your EMS warning come on? If so what stage and at what temp? What is the temp drop on the cooler at high idle, at low idle? These tractors TC's Are the hart of the drive train. EVERYTHING is built around this component. OK, Ouick check, warm tractor, run high idle and get the cross temp of the heat exchanger for TC and Engine, next, raise tractor and then put in gear two or three, preferable two but watch temps, run high idle and start to lay on the brakes and record temps, this is a easy way to find out at what temp the EMS alarm is going off. You should NOT replace any parts untill you have this info at the lest, unless you have a obvious failure of some kind. If I remember the EMS should go on at about 235-245F.for this machine, And the EMS light about the same if not 5 % deg's less. I dont have the spec's in front of me but I am sure someone in these forum does. If you have a problem? it might not be the obvious or even the TC, the steering has a lot to do with this type of tractor!
what was the end result - we've got a d7h second series with almost the same serial number. we've never had this type of problem. Was the problem corrected? Thank you all, this is a great forum
bret191 I think we may have went to Cat ET training with Empire Machinery a few years ago. I'd like to get your email address if that is o.k. Thank you