We have recently aquired a Cat d6c 56 j series dozer with a torque converter problem but we thought originally we may have been able to push it on with another dozer and get it out to civilization that way but for a number of reasons we have had to pull the machine apart where it is.I have been with dozers most of my working life but have very little to do with torque converters apart from just operating them.Apparently the previous owners did the uni joint between the torque converter and transmission and when they replaced it realized it had damaged the rear seal next to it on the torque converter but when they went to replace the seal the shaft in the T.C. came out with it but when they went to push it back in it wouldn't go so they got a porta power pressed it back in but when they started the machine up it refused to move either front or backwards.I have got it to the stage where the T.C. is just about ready to pull out.My problem is I have not seen any sign of recent oil in T.C. housing,scavenger pump,or any of other items that was on the T.C. housing which to me looks like the scavenger pump is doing its job but the oil from the main pump is not getting to the T.C. for whatever reason.What I would like to know is could the problem by any chance not have anything to do with the T.C. but just a problem with the main pump.Any thoughts or suggestions that anyone thinks might help would be greatly appreciated.Obviouslly what I don't want to do is pull out the T.C. and replace it with a recon. one only to find that it was just a problem with the main pump.Thanking you brucew Qld.Aust.
The machine should be pushable with the engine off. You need a good work area for this job. Later Bob
Sounds like the converter may have had to much end play inside and dropped a washer,when they pulled the shaft out.The porta power thing has no dought got things buggard up inside.Be sure to tell the rebuilder about the porta power thing,there is most likly damage that he may not notice otherwise.As for the pump,If the machine was running "moving when the orginal drive shaft repair, was done" Its a pretty safe bet the only damage is to the TC.
Many thanks outasite yes that does make sense to me I was fairly certain when I started pulling it apart that it had to be in the torque converter because apparently it was working ok before the uni let go but when I saw no evidence of oil in the T.C. I thought I better just check to make sure it still could be in the converter and not somewhere else in the machine.
After a few false starts we have just managed to get the torque converter back into the dozer. The problem is we are not dead certain what was actually wrong with it in the first place. The only thing that I could find amiss was that after we had pulled the torque converter out and looked down at the screen in the base of the casing there was a whole heap of muck around it much the same to look at as grease. I had actually undone the plug in the bottom of the casing previous to pulling the torque converter out and only got a little bit of oil and thought that was pretty much all to get out, obviously most of the stuff was too thick to run out. My son took it down to a reputable workshop and they went over it but, because it was done over the holiday period just after christmas as of yet have not been able to find out exactly what the problem was. The problem, particularly as it hasn't been running properly for six months or more we have a lot of metal parts pumps etc. that wont have much in the way of oil in them. Will the pumps be able to draw the oil through or is there places I can put oil in to make sure it pulls the oil through? I cant seem to find anything in workshop manual about this. Any help would be most appreciated brucew
Did you pull trans filter and inspect?
If it's a charge pump that you can open up it would be wise to do so.Clean,inspect,and lube with assembly lube.
I would pull the suction screen by the pump and clean it. You can pour some oil into the line from the suction screen to pump if you want. Make sure the suction screen seals are good if they leak the pump with suck air. Also replace the trans filter before you start.
As recommended above. Start by replacing every o-ring or gasket on the suction side of the trans/tc pump to make sure it doesn't pull air when the machine is running. Especially in older equipment a lot of issues can be caused by pulling air into the suction side of the system. Wash out the suction screen and make sure the seal/gasket between it and the case is good. Replace the transmission filter, cut the old filter open and squeeze a section of it in a vice. Look for metal particles of any type in the bottom of the pleats of the filter, they will give you a good idea of what may have been circulating in the system. Have you had the pump apart yet..? If the torque has been worked on I personally would pull the pump and at least have a look inside it, you may find it's in need of at least a seal kit, maybe it could have even more damage.
Thanks for all your advice most of the things that have been mentioned I have done but will check the rest before it all goes back together hopefully will get back to it next week will let you know how it all goes. Thanking you Brucew
Be sure to get the Torque Divider Planetary in right or it will not drive. Later Bob
And pour a gallon or 2 of oil into converter before you bolt scavenge pump on so the pump has abit of oil for lube to start with is a very good idea !
No go got machine back together fired it up nothing shut it down checked no sign of any oil anywhere near magnetic filter obviously it is not picking up oil into main pump. What I want to know is as main pump is higher than sump in transmission what keeps the pump primed? Is there some sort of check valve between the pump and the transmission and if so where is it exactly.I cant seem to find any reference to one in the workshop manual.
No, just oil on the pump gears makes it draw oil. I think a big rag is down the suction pipe if you don't have a suction leak. Can you fish a wire down it? Later Bob
All this sounds a bit nuts to me, firstly there is no worn washers going to stop the drive shaft poking home into the torque, all you have to do is rotate the shaft to alighn the divider drive and nose bearing, there is oil feed rings on the shaft that take little to no effort to locate, the scavenge pump bolted to the outer case must be removed before the converter case is pulled off the back of the engine, the scavenge pump only pumps the oil in the converter case and should be bolted to the case after the case is bolted to the engine, the transmission pump that is bolted to the engine side of the case can be helped to prime by the small plug/s on in , just squirt in some oil and refit the plug, I am thinking you would have serviced the filter and magnet screen also the scavenge pump screen, on the transmission filter top is a bleed plug that only needs opening a small amount to help things out some, what did the Shop say about the porta power thing damage wise, the damage might be in a bearing still in the flywheel??? tctractors
The damage might be even farther in TC, main thrust web?? Much can be ruined by the push of a button with the wrong thumb. Later Bob
It all beats me how things have managed to go so T*T* up on a simple seal job? plus it would be nice to hear about the repair work that was needed in the converter?? I have a D8H torque job looming up soon, it wont be a " Stuff it full of new bits" thing as the man has at least 3 other units to rob for bits, I will get my Kodak out. Bob that thrust plate and springs I know it needs to be fitted in the correct position with the Flywheel bolts etc, but it would need a right Dummy to stuff that up??? all seems odd from the start. tctractors
Have you had the charge pump off to check it out? They have been know to wear out the drive splines or have problems with the gear drive. First things first would be to get the pump checked out, operating and pressure tested.
OM there is something strange here and hard to see half a world a way. Very easy to see if you have had many of them apart. "No oil flow" has to be a reason ??? Is the pump turning???? TC you want to fit the flange holes neatly over the bolt heads. My biggest concern is people that leave the sun or planet set out and wonder why it will not drive. But you do get oil in the case with that. Later Bob
Just an update on what the problem turned out to be. After finally finding out from the repairer that there was nothing wrong with the torque converter they just resealed and reraced it we realized we had a hydraulic problem rather than a mechanical one we checked out the main pump and found it wasnt pumping. Thought it was just a suction problem as it had been sitting for so long but after trying everything else eventually pulled transmission pump off and found out that when the porta power was applied it didn't do anything to the t.c. but popped the main seal in the pump. Probably fortunate in a way because the spline on pump was worn about the only thing so far that had some real wear issues that we have found so we just bought a new pump and yesterday fired it up and away it went. Seems so simple in hindsight that this is what we should have done from day one but when the problem was all created back at the t.c. you tend to think that the problem has got to be there
Hold on a minute here. Take that old pump apart and look at the side plates. I think you may find one gear has milled into the side plate. If so the worn splines need replacing now or when you install the next new pump. Later Bob
You could well be right Bob and will tell my son this, he actually is the owner of it, at the moment our one and only priority is to shift it off the property he will worry about what he will do with it after that. It is on a very hard to get at property as far as getting a low loader in is concerned particularly if it happens to be wet. We have to walk about 4ks as it is, at least double that if it happens to rain properly. Seems to be a fairly straight old machine what I have seen so far. This is a pic of it yesterday just after I got it going.
Will be okay to walk to float. Spline wear will put end thrust on the drive gear of the pumps unworn spline, forcing the drive gear into the back plate of the pump. Machine looks good, nice size of machine, big enough to work hard and easier to move. Later Bob
I always just grind a little off front edge of the splines on the new pump to overcome the worn internal spline problem , that eliminates the end thrust. This was an idea put out by cat years ago.
Bruce, I'll gladly come and help walk your dozer out if we get enough rain to break this eff'n drought! Cheers, Greg
Seems so ridiculous doesn't it they have still been fixing up the road from the floods a bit over a year ago and their biggest problem has been getting water to stop it from going to powder as soon as they try to grade it. Yes I am sure not only you Greg, but most of rural Qld. would give me a hand if they thought it might make it rain. Bruce