Need to replace some parts in the cable speed control. If I turn the handle a bit to far it flips over inside. Not a great explanation but just need to replace some parts. I can just barely get it to shut down if its held just in the right spot to shut off the fuel. Have adjusted the cable to get some higher rpms and shut down. The plate on top is wallowed out from all the play. It shifts good into all gears, but noticed if I'm in 2nd and push in on the break to turn it slows down both tracks and turns slower then if I was in 1st gear. When its in 1st and I come against a hevy load the tracks do slow down but the engine mostly doesn't change Just now thought I forgot all about replacing the transmission filter since I rebuilt the motor, maybe that?
Picking up the filter tomorrow
Replaced the filter and it was in good shape, so this made no change. The track slows down when pushing a load, does anyone know how it should work? I'm thinking the tracks should say moving the same speed and just spin if the blade stops. The tracks do spin but they slow way down. When filter was removed there was some foam in the oil (had just moved over to flat spot). Have not gotten under it to drain oil and pull screen. Trying to figure out a way to test what might be wrong
Changed the oil, pulled the screen and magnet, all fairly clean. Didn't find any metal or other chunks. Need to get a grease gun hose or other high pressure hose to connect my gauge to the pump output. Starting to think the transmission pump is not delivering the correct pressure. It will go in 1,2,3 and go faster, but try to do anything other then in 1st the tracks stop. Can be in 2 and try to turn and it appears to slow down to 1st and turn
I don't think you will get any track spin in other than first gear. Are your RPMs up to where they belong?
I have the rpm's up pretty high, at least it sounds that way. It's a new rebuilt motor and the I don't hear next to any change, turning of pushing rock/dirt. The thing that really gets me is I'm not pushing that much, or as before, tracks slow way down just to turn. Thanks for your thoughts, 400 looks and no comments
now 500+ views, there is pleanty of knowledge here but guess no one has a clue about transmissions. We allneed to know are limitations
Get pressure readings for transmission pump and for the steering clutches. My spec is for early D3 but should be in the 280 to 300 +/- 15 psi. If pump pressure is good but pressure is low to the steering clutches check the short coupling and o-ring/s that connect transmission controls. A blown o-ring will dump pressure into the transmission.
Thanks Mine has 3 fwd/rev and the manual (27Y) shows where the main pump output is and torque converter, but shows some other locations which I either don't seem to have or unable to determine where they are. Unsure where the clutch points are (have looked) but going to have to look some more
Check pump pressure at the test plug on the transmission filter housing. I'm not sure where you test steering clutch supply pressure to the control valves on the D3. Service manual should say. May not even have one. The common/candidate leak source is Item 1 of the 9P5695 Transmission Hydraulic Control Group, page 70 in my 27Y parts book. This is a common type connection on all powershift transmission controls and is first item check for leaks.
I don't know if the rollers on the steering clutch linkage being worn out would cause this problem or not. To check the steering clutch actuators pressure is done from the outside in front of the sprockets on a 931B so is likely the same place on a dozer. There's a hole in the frame to get at the plug.
Hope it stops raining so I can do some checking. Still need to get a pressure line to connect my gauge
Checking at those ports is after the steering clutch control valves. Preferred system pressure check is before the control valves. Got to looking at the configurations and the supply to the control valves is on a block next to the transmission filter. To close to the filter to have any significant difference in pressure so go with the filter port for pressure check.
Some times your better off with no replies than a lot of bogus info from someone who has never seen a D-3 transmission. Bob
Maybe, but sorting thru even something in error might bring up an idea which could be useful
Thought I was going to get some readings today, but need a different fitting. Its smaller then 1/2 NPT and larger then 1/4 NPT but have not found a nut that will screw on it either. One on the right is the plug. Probably another trip to the hardware store
Plug is a -06 o-ring boss fitting (9/16-18 tpi)
Thanks, will look for one of those
Huh? Plug is what you have, need an adapter to get from 0-ring boss fitting to whatever your trying to connect.
Or you could drill and tap your plug 1/8" pipe to fit your grease hose. Bob
Ahhh I think I got it. (light bulb) I can drill and tap for 1/8 NPT (not enough room for 1/4) then adapt up to my 1/4 npt
You said you had a grease gun hose they are usually 1/8 pipe, if you go for fittings get a 7/16-18 STOR boss fitting for your steering clutch fittings. Bob
I was going to get a grease gun hose but since I had a few short hydraulic hoses laying around (14 npt) just started to use one of them. My gauge (400 psi) is also 1/4 Maybe swing by Fastenal and see what I can find. Looked it up and see 7/16-20 but no 18 thread
Mind said 20 fingers typed 18. Bob
That's why I'm not the expert. LoL I just knew you could check some kind of steering pressure there.
OM has never seen a D-3 transmission you have worked on one. checking steering clutch pressure after pump pressure is a good move to see if clutch valves are releasing ,springs get weak and spool will stick , clutch will slip. Bob
It's comments like that are the reason it's hard to get people to respond with recommendations to requests for help. Bluox ought to start out by learning about hydraulic fittings.
Fastenal didn't have anything so stopped in at CAT in Sumerset. They didn't have any fittings to sell but the mechanic came out and we walked to his service truck. Pulled out all the fittings, gauges and hoses and said I could borrow them, could have pushed me over with a feather. Wow, never would have thought they would offer that Was also talking about the 1/8 NPT and could do that just as easy. So I thanked him for the help an the offer but decided to just drill and tap later. I'm a ways from Sumerset an while I could run back over, I didn't want to use his stuff unless there was no other way. Nice to know if I need to I can take another triip for some help
Its dry and pulled the plug then looked for the drill bit for the 1/8 NPT. The plug from threads to top of nut is about 5/8, the tap from start to get enough threads to hold is about 1/2 inch deep. That means I'm almost out the end of the plug and have thinned the walls, so don't think this will work. Started looking for a hydraulic test kit and find some china stuff for under 100 and everything in between to over 2000. Anyone have any insight to a decent kit to get with the fittings I need. Have no issue buying good tools, can always use later, but the 2K is a bit much to justify right now Edit: think I'm going to also post this in another section due to tools question Belay that, doesn't appear to be a section for tools
That's a pretty ignorant comment and what makes you think I've worked on one. I only found out about the plugs on the side when I asked if I have to bleed the valves after having them checked out. It cost me 7K to have the steering clutches rebuilt and new brake bands. I pulled and replaced them. There are a few members on this forum who I'd consider guru's on different aspects of Cat equipment. You're not one of them. Old Magnet and Nige are 2 of those guru's. TC Tractor was another one and it's comments like yours that caused him to leave. With no offence to a lot of very knowledgeable experts, the absolute guru on the smaller Cats was another Bob who we unfortunately lost. He had issues with you as well and I suspect that's why you've only recently started posting again. Part of being an expert is knowing how to offer a different suggestion without insulting another poster. TC Tractor and Bob/Ont are very missed on this forum. When you were away not so much!
Have the new test gauges and was able to test filter pressure and its just under 400 psi. When I shift to any gear (FWD/REV- 1,2,3) it drops to zero and then comes back up. The Dusichin gauges came with several adapters but need a simple i/8 to 1/4 NPT to measure at the clutches More to come later
I'm not getting any pressure at the steering clutch control valve, but it does still move fwd/rev
That's because there is nothing there. Check pressure at ports in front of sprockets. Bob
My manual shows a clutch port just in front of the sprocket on the outside under the rails, is the where you mean?
Yes. Bob
Only getting about 90 psi, being read on a 0-3500 psi gauge. So it might be 100 This was read when the pedal is depressed, released reads zero. Only read right side because the hex head on the left is messed up
Get a 0-500 or 0-1000 gauge and figure out how to get plug out. My guess would be bad springs or spool sticking in valve. But bear in mind I'm only a ignorant old mechanic who worked around this stuff for 50 years. Bob
Do understand the accuracy, but when I measured using the same gauge at the filter it read 370 to 380 psi. So I'm figuring that it is low, no matter what gauge I use. I do have a 0-400 but don't have the fittings to get it hooked up. The sprocket connector is a 7/16 o ring, and the other end is some sort of fitting that Dusichin uses. Was at a store today trying to find something to use my other gauge, but no luck. I have this test kit https://www.amazon.com/DUSICHIN-DUS...D=51lwaJu2SRL&preST=_SY300_QL70_&dpSrc=detail
My thought is the pump is putting out the correct pressure. Manual states the clutch pressure should be the same at 375 +/- 15 and needs a minimum of 270 to release steering clutches. With only getting 100 then the clutches should not be releasing, yet I can turn if only in 1st gear. So does this machine use springs to engage clutches and hydraulics to release, or hydraulics both ways? If it is the spool valve, where is it?
The valve where you were first hooked up has the springs in it. you have been powering thru the clutch only trying to release. Take the hose fitting off the gauge it may be pipe thread. Bob
Sorry Bob for all the dumb questions, but if the dozer is in any gear other then 1st, and I try to push/dig much of anything the tracks stop. When they stop there isn't much reduction if any in the motors rpm. While I can see if the fitting can be removed from the new gauge so I can try to use it on my old gauge, if the pressures I'm seeing are accurate, what would this tell you? 380 at the filter and 100 at the clutch. One thing I did realize while reading the manual, the clutch reading said to measure while low/high idle, and the center brake held, in 3rd gear stalling the torque converter. I took the reading but was in 1st with both clutch/break pedals depressed
Get a smaller gauge and run the whole transmission pressure test start to finish and see what you get. That tractor just has a torque convertor and operates a bit different than a bigger tractor. Bob
Bought more stuff Filter is a hair under 400 psi low idle and 401 at high idle Steering clutch 230 to 240 low to high idle with clutch pushed in and zero in 1,2 or 3rd gear with center brake held in at low of high idle
Bump hope maybe I can get some thoughts
Hey Bob, can you assist? For that matter anyone else have a guess?
Gess guys, I went from getting some info to none. Old Mag, Welder, and Bob and now cannot get anyone to help. Sorry guys, but sure don't see where I said anything to tick anyone off. Sorry of I did but sure don't see anything that should have done it, I want all the input just to have something to go by
Your not the problem. According to Bob he's the only one qualified to answer and proceeds to attack anyone who responds.
Thanks, was getting real worried I did something. I'll take anyone and everyone's thoughts, guesses, known facts. I've even sent messages to others here which here and no responses from them either.
Look in your service manual for form SENR7917 power shift transmission testing and adjustments and follow the pressure checking chart . start at the top and go to the end writing down your results .If indicated check linkage adjustments .We aren't there and can't see your machine so you need to follow the service manual to get good results . Or you can use the Cat guru shotgun method and start replacing random parts and hope for the best. Good luck Bob
Have not seen one person on this thread say anything about any part that needs to be replaced, so there has been no shotgun nor 22 rifle being used on anything yet. Only get different gauges and more parts for testing. I go thru all this testing, buy more stuff to get you what you say you need, and in the end I need to go back thru everything in the manual. So the new pressure readings that you wanted get me no closer then I was before. Not even a guess right now, that its either this or that. Not that I'm going to start throwing parts at it, just give an ever so slight idea what I'm getting close to, and what needs to be done to verify. Thanks but I don't need this kind of help, have a good life
Working on this one off line, if anyone has any suggestions please post. Once problem has been determined and fixed will update in case someone in the future would like to read