I have oil dripping out of where the starter meets the torque converter housing on my 94 D4H LGP SER# 9GJ01015. The oil looks light like trans or hydraulic oil, not engine oil. The fuel filter is above the starter but it’s definitely not diesel. My thought is it’s oil from a leak in the torque converter making its way out along the gear, or do these big starters have oil in them? No signs of any other leaks above the starter that I can see. I posted a video of it here—— Thanks as always. T
Scavenge pump not keeping up with torque converter leakage. Oil is being slung around inside housing and typically leaks out at starter mount. Other symptoms are loss of power and oil overheating plus foaming at vent if it has one.
Thanks for your reply Old Magnet. I looked in my shop manual and parts manuals and don’t see any reference to a scavage pump for the torque converter. According to the manual there is what they call a Power Train Oil Pump which the book says is fastened to the torque converter housing. Is that the one?
Do you have a Parts Manual.? If you have check if there is a trash screen somewhere close to where the oil drains out of the torque converter.
Not familiar with a D4H but one other thing to consider is a plugged breather anywhere in the system. I had problems with a couple 980G loaders that some genius at Cat decided to mount breathers out of site on the top of the transmission and tucked into a pocket in the casting almost designed to collect dirt. After figuring out the problem relocated up high and in plain sight with a hose going to the original location. Never had a plugged breather again and the routine cleaning was done in seconds, spin one off, spin clean one on. Then flush out the old one for next machine needing service.
I don’t see any mention of a screen in the factory parts manual. At least not as a part of the torque converter. Looking at the OM manual for a D4H Series II (mine is a Series III for some reason the Series III OM manual did not come in my Factory Service Manual from eBay ) it mentions removing the plug, seal spring and screen from the scavenge line on the bottom of the torque converter. I plan to drain the trans/bevel gear case and clean the bottom screen and magnet as well as change the upper filter. I will have to find this scavenge screen and clean it too. The pic in the OM manual of its’ location is about worthless. You sir may very well be onto something here. I just bought this machine and am working on a number of repairs and maintenance items before I try to start using it. Here’s a pic of my trans breather which coincidentally I just found yesterday while working on transmission shift linkage problems. From the looks of it, it hasn’t been cleaned in the last half million hours.
It’ll be shown in the torque converter lines group, not the converter itself.
Does #53 they call it a suction screen and #60 they call it a filter magnet look like the right parts to you Nige? That’s the magnet and screen I wanted to drain the transmission oil to clean while I have the pans off. I think those may be the correct ones, it just threw me off because they are mounted to the case not the torque converter. I’ll definitely clean the breather too.
Those are not the ones I was thinking about. It appears as though your machine doesn’t have a screen in that area which would be where hose #23 connects to the converter. Remove that hose and blow through it. However if you have never removed and cleaned the suction screen and the magnet before it would be worthwhile to do it. If you find anything significant on it take photos and post them up. When you drain the oil check the colour and the smell. Also you should clean or replace the breather on top of the transmission case.
Ok here's what I have so far. Drained the trans oil today what was left of it, probably a few gallons low. No wonder the drain plug was dripping since it was loose and didn't have an o-ring on it. Ugh. Anyway the oil does not smell burned and it's not black in color like diesel engine oil gets, but it's dark enough that I'm going to put new in. I pulled the lower screen and magnet and they were not too dirty in my opinion. See pics I wonder if the mechanic that had worked on this thing prior to my buying it cleaned them maybe. If so, then I would have thought he would have put an o-ring on the plug and tightened it. Anyway there were several metal chips on the screen/magnet see attached photo. I should mention that what I was told when I bought this was that the previous owner was using the dozer and it broke down in the woods. Supposedly the problem was diagnosed to be a broken transmission pump shaft which he had the mechanic fix. Not sure if that's where the small pieces of metal could have come from or not. I also pulled the upper large transmission filter cartridge and it looked very clean. It was not the type that I could cut open, but I did not see any large debris inside or out. I also sucked out the oil in the bottom of the cartridge sump, and there was no metal hiding down in the bottom of there either. I also cleaned the breather and it's 100% clear now. I'm still working on trying to figure out which hose is hose #23 on the machine. There are so many hoses crammed into such a small tight area there. Nige if I can only get to one end of hose #23 is it ok to hit it with compressed air toward the transmission end, or do I need to get the hose unhooked off both ends to keep from blowing any blockage into the trans if there is one in the hose?
Yes, that would work. #23 should be easy to find because it's the only one with hose clips on the ends. All the others are flanged hydraulic hoses. That's if the illustration you posted above is ACTUALLY correct for your tractor. The oil should be a light straw colour, clear & bright. Anything less than that the oil is f'ked. Your screen has particles of burned clutch material in it, not many but it all depends on when the screen was last removed and cleaned.? The metal particles are also worrying, can you post some better photos.?
Not to wish bad luck on anyone but not knowing how long since those filters and screens have been out and cleaned it's anyone guess how bad they really are. Couple questions or thoughts. You say the guy you got this machine from said he had a mechanic replace a broken pump shaft. Is there anyway you can get in touch with this mechanic to get the information straight from him? I'd let him know you are not trying to blame him for what is happening now just trying to get the full story. It may just be me but I'd love to be able to look at the failed pump. It could tell you a lot of why it failed. I worked on mostly medium to larger size Cat loaders for 40+ years and can't recall one transmission pump that broke a shaft. Did replace or rebuild many but to break a shaft sounds odd. I seem to recall some pumps with driven shafts that were pretty thin between the splined end and the pumping gears. I assume that was to act as a "fuse" of sorts to protect other parts from damage. The condition of filters and strainers often depends on how long they have been in service. Big difference between say knowing they were in there for 1-2,000 hours or just long enough to load on truck to deliver to your site
Actually when I bought the dozer it was the mechanic I was dealing with. I only spoke with the owner of the thing briefly on the phone. The skeptic in me says that allows plausible deniability. The dozer was at parked at the mechanic's shop where it had been for over a year since he had repaired it and the owner started trying to sell it for much more than I paid for it. I'm pretty sure the mechanic and the seller had an ongoing relationship where the seller owns a bit of property and the mechanic works on the guy's personal equipment in addition to working on other people's equipment as well. I could have the story wrong from my failing memory, but from what I remember he told me it was a broken trans pump input shaft. I took some pics when I was under there today of what looks like some new pump parts to me. These pics are taken after I did a lot of pressure washing on the thing though. The belly pan under the middle of the dozer (where the trans pump, drive shaft, torque converter ect are) was clean when I took it down so I know he had that down. The forward two pans were all caked up and looked like they hadn't been down in years.
I planned on saving the metal particles in case you asked for more pics of them Nige, then a wind blew threw my garage this afternoon and blew the paper towel that I had them on on the floor with all the other rust flakes and metal particles that happen to be there from working on this old thing. Sorry but that's the best I have. The below two are all I have other than the one I already posted. I got hose #23 off, man was that a tough one. It is a short section of hose but has metal braid in it like a hydraulic hose. The hose looks like it's open wide, however the outer rubber covering is very soft (breaking down) and had some worn through spots. I'm going to replace it. The inner lining seems very hard.
Best way to stop oil leaks---don't start it up, best truck one that's fence rowed with flower baskets hanging from the mirrors,
Nige any need to worry about hose #29 possibly being plugged up or having a vacuum leak causing the oil leak? It's a much smaller diameter than #23 and like I said above, I'm just going to replace #23.
If I'm honest I would say replace them both.
They look a bit like remnants of a bearing cage but I wouldn't swear to that.
Ok. I’m heading to the dealer today I’ll grab both and hopefully between the two hoses and the cleaned breather that will take care of the oil leak at the starter.
Not sure what to do on this, praying that it’s parts from the prior pump failure. Really don’t want to start tearing things apart looking for a problem that may not be there. I guess I’ll put new trans oil in and see how things go when I actually get her going.
That can be a big problem with a used machine, not knowing full history! If you did know what was found in an earlier problem and these parts matched then you might think they were some that were missed before. Hard to tell from the pictures, are those larger bits metal or plastic/fiber of some knid?
The bits in the filter screen were fiber or plastic I would say. Maybe even some small grit like sand which is everywhere down here. The other pic with the penny were ferrous metal and I picked them out of the cage ends of the strainer magnet. I agree with you 100% buying anything used especially heavy equipment is a roll of the dice. You do the best you can to check things out in your price range and hope for the best when you really start digging into the one you buy. The more times you roll the dice though the higher the odds you’ll get bit eventually. Heck some of the dozers I looked at had no antifreeze in them, no oil in the finals, and cracked track frames. Prices on total junk are through the roof like everything else.
Burned clutch disc friction material can look like sand. Just sayin’
You’re not filling me with optimism Nige.
See the comments in post #11 on Page 1. It looked like there were some fair-sized pieces of burned friction material in the screen when you removed it. You may be correct that the smaller ones you discovered today were grains of sand, I was simply pointing out that there is another possibility. Now all those particles may be from a previous failure that hasn't been cleaned out properly but I wouldn't bet the farm on it.
Again that is one of the things one has to understand when buying anything used.
So if it is clutch material from a current or impending problem, what can I expect to happen? Will it eventually stop pulling on one side or both sides at which time I'd have to do clutches?
I’m referring to the transmission clutches, of which there are five - Fwd, Rev, 1st, 2nd, & 3rd. A direction and a speed clutch are required to engage any gear. A failure of a clutch would cause you to lose drive in either forward or reverse, or you would lose a specific speed (e.g.1st) in both directions.
I was doing a little research last night on YouTube and I think I’m starting to get the idea on how these are set up. Is it correct that when you pull the trans out of the rear of the machine, all of the clutches are contained in the trans. No clutches left in the machine that handle steering for this type of machine? From the videos I was watching it looked like the worst part of the job was handling the weight of the thing and keeping track of where all the parts go when you take one apart. Looked like clutch discs and steel discs were a little over $200 each from Cat if I have to go that route. I think it was six of each worst case scenario plus any other parts.
All the transmission clutches come out with the trans and it is those that produce the wear particles that landed in that magnetic screen you cleaned out the other day. The steering clutches are in the final drive units on each side, along with the brakes. So long as the machine is steering OK side to side I don't think you need to worry about them at this time.
Lol you’re too fast for me Nige. I was just reading through the Systems Operation section of my Cat Service Manual and saw that there are also steering and break clutches. Was going to edit my post but you’re too quick. You’re a good man Mr Nige. Thank You as always.
Ok so I replaced both of the hoses, cleaned the screen and magnet, put in a new upper filter, and I also drained the oil from the torque converter housing using the bottom drain plug. I replaced the trans oil and after less than an hour of use, it's leaking from the starter area again. Anyone have anymore thoughts or is about the only thing left to pull the torque converter out to find out what o-rings or seals are bad to stop this leak?
I would suggest to measure the torque converter inlet & outlet pressures using the test & adjust procedure attached. Inlet pressure should be max 145psi with cold transmission oil and the engine at high idle. Outlet pressure should be 42+/-5psi in a converter stall condition. In other words oil at normal operating temperature, brakes applied, transmission in 3rd speed forward and engine governor control at maximum throttle. Report your results.
Thanks for the help Nige. This kind of testing will be a first for me, so please bear with me. I know it's rudimentary for techs, but it's not something I've done before as a DIY guy. So would I use a hydraulic pressure test kit to do this test? If so, I'll have buy a kit since I don't have one. I've seen some other posts where people have purchased them on Amazon and so forth. Do you know what kind or kinds of fittings I would need to hook up to the test ports?
I think at this point you have to ask yourself the question are you moving out of your comfort/competence zone and would it be wise to think about bringing someone in to do the work for you.
Unfortunately not an option for me, nor a desire to be truthful. I’m pretty much stuck on my own, not only due to living out in the sticks, but finding people who are actually competent and want to work these days is nearly impossible. I’ll have to figure it out and buy or make whatever is necessary to get the job done. Otherwise I guess I’ll have to let it just keep leaking oil. The only way I've really ever learned anything is by doing it myself, so I'm sure it's not above my level. Maybe not familiar or experienced yet, but not above my abilities for sure. The only way I can afford to have the equipment I have is to do the service and repairs myself, no other option. Hydraulic test kit ordered, should be here on Saturday.
Ok Nige it took me a little longer than I thought it would to get it done, but I did the torque converter pressure tests done today. Inlet pressure cold was 135 psi cold. You said to check it at "high idle". There is no detent on my governor control for a high idle position nor is there a tach on the machine, so that reading was taken at full throttle. The Outlet Pressure fully warmed up ( I had been pushing dirt with it for at least an hour to an hour and a half in near 100F outside temps prior to taking the reading so it was definitely fully warmed up) was 60 psi in 3rd gear at full throttle holding it with the brakes forcing the torque converter to stall.
That's fine. High Idle is the maximum RPM that the engine can achieve solely turning the parasitic loads (fan, alternator, etc) attached to it. 135psi is about what would be expected. The spec states 145psi maximum. The Outlet pressure is worryingly high. The spec is 42+/-5psi under the conditions that you made the test that gave you the 60psi result. What is the maximum psi reading of the gauge that you are using.? I suggest that you remove the TC outlet relief valve and carefully disassemble it. Look for any signs of damage, scoring of the spool or in the body, the condition of the spring, etc. Compare the spring dimensions to the specification. Inspect all the gaskets, seals, etc. Also note how many thick/thin shims #14 are behind the spring. Do they look original or has someone slipped a washer in there.? The parts breakdown is attached. Post all the answers to the above quesitons before you reassemble it.
The gauge is a 150 PSI max. I'll pull the relief valve and let you know what I find. Thanks
Then it should be reasonably accurate even when measuring 60psi. BTW the photo shows 65psi. Was that the reading you took for the converter outlet pressure.?
Well now I think think I messed up when I told you 60 psi in the post above. The pic above is a screen shot from one of the videos I did while doing the test. I made a video of the gauge so I could go back and zoom in and check the numbers after the fact. Trying to hold the gauge, phone, sitting on a bucket since I don't have the seat in right now, and not kill myself in the mean time with the floor out in the heat ect. Anyway You're right that reading is 65 not 60 as I stated. But here's the thing. I did the test several times to make sure I was doing it right and I just watched all of the videos. The last two videos from the tests I made are actually showing around 40 psi, not 65 psi like in that photo I posted. I think I was doing something wrong the first couple of times I tried it. I may have selected the wrong gear originally or something else, can't really remember what, but the last two times I did the test, I got the same results at the 40 psi mark. I know the torque converter temp started to get hot from stalling it and I had to let it cool down by running normally in between tests. Initially I was holding it in a stall condition a little too long causing it to start to heat up. Maybe the relief is sticking sometimes which would have caused the higher 65psi pressure that I saw initially? Although if I did not do one of the test parameters correctly then the pressure could be off from that I presume. I apologize for the wrong info, I should have watched all the videos before I posted. The below two pics are stills one from each of the last two tests that I did.
I can't understand why you would get 65psi in earlier tests and 40psi in the later ones provided that the conditions were the same. You need to be hard on the brakes, 3rd speed forward, throttle wide open. Don't stall the torque converter any longer than you need to get a steady outlet pressure reading, at that point flick the transmission into neutral with the engine at medium RPM to allow the system to cool down. As you found stalling the converter creates a lot of heat.
I agree, the only thing I can assume is that all of the conditions were not the same. As I said I was doing the test by myself, trying to hold the gauge in my left hand after shifting into third gear and my phone in my right hand while sitting on a 5 gallon bucket and trying to watch to make sure that the small plastic hose for the gauge didn't get kinked or damaged in some other way and pushing hard on the brake at the same time. I ran the test three times with the same results on #2 and #3, so I must assume I did something wrong on #1. With all that said if the 40 psi readings are correct, what's the next thing you suggest on this torque converter oil leak?
I'd like to hear some other opinions, but my thought would be that if the converter inlet & outlet pressures are within specification then the next thing I would be planning is to drop the belly guard(s) under the torque converter to access the big plug on the bottom of the converter housing. Run the machine starting from cold with the converter stalled for 30 seconds or so, shift to neutral & drop the RPM to Low Idle, then after 10 seconds or so shut the engine down. Pull the plug #16 on the bottom of the converter housing and measure how much oil drains out of it. Make sure you have a big bucket and beware the oil might be hotter than you think.
Ok I can do that. the belly pans are already off from the other work I've been doing to it. I pulled that drain plug once already and drained the converter when I changed the trans oil and the two hoses that I changed earlier in this thread. At that time I bet there was at least two or three gallons of oil that came out of there. I suspect since it is pushing the oil out at the starter again, that it is already full of the same amount of oil in there again. Should I drain it prior to doing this test to see how much oil is actually accumulated during this test? Otherwise I think it will be full of oil like it was before I drained it the first time. In order to get a base line on how much oil leaks out during this test, I would think I should drain it to empty first then do the test. Just want to confirm.... Also what Throttle position and gear should I stall the torque convert in? 3rd at full throttle?
Yes. Drain it before you start. Then as above start the engine, stall the converter, shift to neutral, idle a few seconds, shut down.
Got it up on blocks and drained the torque converter. Got 10 measured cups (16 cups in a gallon for reference) of oil out when I did the initial drain. Can't do the test today due to the fact that it's thunder storming now. Seemed like I drained more oil out of it the first time, but that's just a guess since I didn't measure what came out. Hopefully I'll do the stall test tomorrow and let you know the results from that. Thanks
Not familiar with this machine, does the oil drain from converter by gravity or is there a scavenging pump involved?
Gravity drain. No scavenge pump. That’s what caught me out at the start. That’s one of the reasons why it was suggested to investigate the drain hose(s) between the converter housing and the transmission.
kshansen thanks for chiming in. Nige I'm not sure that there is not some sort of pump or at least suction on those two lines that I replaced. Both of those lines run up hill to the fittings that they attach to on the upper right side of the trans bulkhead. They actually come out of the converter and bend 90 degrees upward to attach to 90 degree fittings coming out of the bulkhead right next to each other. Since they run uphill, if they are meant to remove oil from the converter there has to be some kind of suction designed into them I would think.
Shouldn't the starter be sealed and have a gasket at the housing? Since there's oil in the case.
Well I'll be doggone you're right. There is a gasket that goes between the starter and mounting surface shown in the parts book. I'll have to pull the starter and see if there's one there and what kind of condition it's in. I'll replace it to see if that cures the problem. I never even thought of that. Awesome, thanks oarwhat.
Nige I did the test today and got the same amount of oil out of the torque converter after the 30 second stall test - 10 cups. I would think that would make sense though since that's probably how much oil it takes to fill the converter housing???
If the converter was flooding I would have thought that 2-3 gallons of oil in the housing would be more likely than what you got out.
Those wet starters also have a shaft seal inside to keep oil out of the windings. It is between the drive section and the winding/armature section. Anything with a wet flywheel housing requires a sealed starter
Thanks for the info 56wrench. This is my first experience with a wet starter. I'll keep that seal in mind as well. Done many dry starters but this is a new kind of thing for me. I appreciate the info, and am enjoying learning about stuff I didn't know even existed.
Well I thought I had the torque converter leak fixed, but no bueno. I changed the gasket on the starter which had obviously been reused, and there was no leak with just running the engine with the dozer parked. Today I actually used the dozer for the first time since changing the gasket for about three hours, and the leak is back the same as before. Not sure if this problem is related or not (I doubt it, but I'm also having a problem with the dozer sporadicly not going into reverse or forward (reverse is far more common than forward) after I've used it for about two hours or so. It works fine for the first two hours or so, then this problem starts to occur. I might have to shift in and out of reverse (or forward) two or three times to get it to go into gear. I am usually operating in 1st gear only, but it doesn't matter because if it does not go into gear (whether reverse or forward) pulling back into 2nd or 3rd gear still does not make it go into gear. I've lubricated and adjusted the linkage so that's not the problem, and like I said it works like a charm for the first two hours or so. I'm thinking the shifting problem is an o-ring or seal somewhere.