Hey Guys, I need your help. I have two D2 5j's and have starting motor clutch/pinion problems with both. The first one is missing the pinion engaging handle and shaft. The other one engages extremely hard to the point that the handle has been broken off and a flattened end of a 18" piece of black iron pipe is hammered over the stub. It will start the diesel but does not seem to fully engage. Also on #2 the ball bearing on the outboard end of the pinion shaft is shot, and I can't get the nut off the shaft so that I can replace it, as the shaft spins and I don't know how to hold it to get the nut off. Please help! What do I have to do to get my kittys purring? How much trouble am I in here? Thanks for any information you can give me. Oldparker

I think you want to pull the pinion assembly and fix it right before you're stuck in a hole somewhere. The only thing you can't fix out on the bench is the engagement rod and finger on the end which will still be in the clutch housing. The pony motor has to be lifted up a couple inches or removed completely to allow the pinion to come out. This involves the cooling system and the pony oil sump, so drain both ahead of time if you go that route. Also be advised that there is ALWAYS another bolt or nut holding the pony down, so if it doesn't pop right up, scrape around down in between the diesel engine head and the pony motor and find that last nut!

If you want to just replace that bearing in place, try engaging the pinion into the diesel flywheel and engage the main clutch and put the transmission in gear etc. You might be able to spray the pinion latches and engagement collar etc and check for missing parts by looking into the main clutch housing through the clutch adjustment opening or through a small 2 bolt cover next to the left brake pedal that is for access to the pinion latch adjustment screws.

Hey CCJersey,

Thanks for the information. I'm glad you didn't tell me I had to pull the diesel motor! I'll get into it again next week and try the things you've told me. I really appreciate the help. What do you think about the missing pinion shaft on the #1 D2? Can it be replaced without pulling the diesel? It looks like the hole for it is accesable from the outside, but I don't know what the shaft looks like or whether it can be inserted into the hole. Thanks again. Oldparker

No, Sorry! The pinion engagement "bar" has to come in through the clutch housing from the rear. It has what I called the "finger" (that pulls the pinion gear into mesh with the flywheel gear) made on the end of it. Generally sort of an 'L' shaped piece.

No chance it's still in the housing, just pushed back to the rear so far that the end of it isn't visible in the front? It's spring loaded to pull it back from the engaged pinion so when the pinion latches release, the pinion gear can go back to the resting position.

Hey CC Jersey, Thanks to you for your suggestions. Got the nut off the front end, pulled the bearing housing and braking discs. Replaced all the chewed up parts with ones from my parts tractor, cleaned everything up good and reassembled. Took off the little round cover for the pinion latch and after a half can of WD40 everything freed up and moves smoothly.
Now my problems are that I can't keep oil in the clutch housing, and I don't know where it is going. The parts book shows a seal in back of the rear pinion bearing. Is that the problem and can I get at this by pulling the pony motor and pulling out the clutch housing?
The other problem is that the clutch fingers don't quite engage unless it give it a push on the end of the sleeve through the little hole. Is there an adjustment anywhere to get about an eighth inch more travel?
Also, can you date my two D2's? One is 5J2766SP and the other is 5J7078SP ?
Thanks for any more help you can give me. Caterpillars are new to me and this is a learning experience in heavy equipment. I have been a millwright most of my life installing heavy machinery but never any experience with diesels or tracked equipment. The D2's are my retirement playthings, and I'd like to get these problems resolved before my real project - pulliing the final drive housings to replace the horrible stuck steering clutch discs. I've read all I can find, but I'll probably need help from you guys on that one too. Thanks again!

hello oldparker ,here are the yrs built of your d2's ,bruce oz

5J2766SP=1940
5J7078SP=1945

Thanks Bruce, I appreciate the information. John

There is a pinion shaft seal in the rear of the pinion housing, if that is leaking the oil would be going into the diesel engine's bellhousing. There is also a large o-ring around the pinion clutch housing that seals to the bellhousing that could leak oil to the same place. The pinion clutch housing assembly has to be removed to access these.

As for the pinion sleeve travel, I wonder if the pinion clutch is properly adjusted? Can you feel a definite snap as you engage the pony clutch lever? If not you can adjust the pinion clutch through the access hole on the top of the pinion clutch housing.

Hi Toby, My 5J only has a filler plug on the top of the clutch housing. It is only the later 5U's that had the rectangular cover on the top. What do you adjust in there? Also, will the O ring and the seal come out when I remove the pony motor and pull the pinion assembly?

Yes, you remove the whole pinion assembly to replace the seal. I have seen some running without oil too. That oil lubes the camshaft drive gears on the pony motor as well as the pinion/idler gear train, so it's important.

The pinion engagement lever could be bent, pivots worn, linkage worn etc. You're so close, just figure out where the slack is and eliminate it if possible. You may also find that the pinion latches and collar etc are worn as well if you look them over closely while you have it out.

The clutch adjustment inside the housing like you have is the same as the other later style, but you have to reach inside through the plug hole and pull the latch pin with a screwdriver while turning the pony motor flywheel by hand to tighten or loosen the clutch adjustment collar as needed. The pinion clutch doesn't need to have a hard snap to pull the main engine. Just a definite snap is usually enough and you have less problem with the clutch dragging and making the pinion hard to engage.