John Deere 310C won’t go forward after rebuild, new hydraulic leak.

wisdumb · Apr 26, 2026

I just rebuild the reverser because my tractor would not go forward only reverse. I used a kit with new clutches, seals and oil pump. I also flushed the oil cooler and torque converter with atf because there was metal and brass in the oil pan before the rebuild. The tractor still will not go forward after the rebuild, but hopefully it’s due to this hydraulic leak.

I have a big steady leak of hydraulic oil leaking through the threads of the T fitting with the sensor on the passenger side of the reverser. I’ve removed and installed the fitting 6 different times and tried to use oil rated pipe tape but it just comes off even though I’m threading it on clockwise. I even did it once counter clockwise just to see if I was loosing it. It doesn’t feel cross threaded. I can hand tighten the fitting all the way down to the end of the threads before it gets tight?
I know I need to fix this leak first before I can troubleshoot the reverser, which hopefully will work after the leak is fixed. Any help will be appreciated. Should I use pipe dope?

mg2361 · Apr 27, 2026

Welcome to HEF wisdumb

!

Go get yourself a new threaded nipple to put in there. Threads do not look right.

Did you adjust the clutch pack endplay to specs when you installed the new clutches?

Tinkerer · Apr 27, 2026

iIt looks to me like it is some kind of ORF fitting.
Kinda like this one.

HarleyHappy · Apr 27, 2026

Not a NPTF fitting. You should try an o-ring but possibly threads are screwed up. May want to try a different T fitting that is NPTF.

wisdumb · Apr 29, 2026

Thanks for the replies!
I also noticed a chip out of the casting of the reverser. I think that’s why it would tear off my pipe tape. I put a hydraulic rated paste on it and let it dry for 32 hours and it still leaked. But I could tighten that fitting down all the way by hand.

What type of fitting is this if not npt?

Mg2361 I did not adjust the clutch packs I just put whatever snap ring fit. I didn’t know there was an adjustment. Are they that finicky that it will mess it up.?

Thanks again for the help.

wisdumb · Apr 29, 2026

Also the seals numbered “2” are the only seals that I reused the old ones. The kit from broken tractor had seals for it but they were obviously too large. I’m not sure what the function of those two seals are.

mg2361 · Apr 29, 2026

First, that threaded port in the reverser is definitely a pipe thread. I would suggest getting a new nipple like I posted above.

wisdumb said:
I did not adjust the clutch packs I just put whatever snap ring fit.

Specific snap rings go into specific spots. For example, snap ring 14 must be .090"-.093" thick. Snap ring #16 must be .074"-.078" thick. Then you have to have a clutch pack clearance of .021"-.036" which is set by snap ring #6, which comes in 5 different sizes.

If the clutch pack end play is too great, you could end up in a situation where the piston travels all the way, but does not sufficiently compress the clutches.

wisdumb said:
Also the seals numbered “2” are the only seals that I reused the old ones. The kit from broken tractor had seals for it but they were obviously too large. I’m not sure what the function of those two seals are.

Those seals are for the forward clutch circuit. If those seals are damaged or shot, you could lose forward clutch pressure.

wisdumb · Apr 29, 2026

Mg2361 thank you for all the information. I ordered the technical manual and the forward piston seals. Looks like I will be pulling the reverser back out this weekend. I will keep you posted as I go.

wisdumb · May 1, 2026

Sealant only helped a little before it leaked again.
I got a new nipple in pipe thread I will put it back on retest. If the tractor still doesn’t move then I will pull out the reverser tomorrow and check the clearances in the clutch pack and replace those 2 old seals.

Thanks for the help.

wisdumb · May 2, 2026

How do you test the clutch pack end play? Sorry my manual has yet to show up.

mg2361 · May 3, 2026

wisdumb said:
How do you test the clutch pack end play?

With feeler blades.

Check your messages.

wisdumb · May 4, 2026

Thanks mg2361.

I installed the new seals and adjusted the clutch pack per the specs you gave me. It’s all out back together and installed in the backhoe.
I got a new threaded pipe nipple and it threads in tight as pipe thread should. Installed the fitting with pipe dope and tape last night. I used

Permatex High Performance Thread Sealant 56521

Directions on the sealant say it doesn’t fully cure for 72 hours! I won’t mess with it tonight but I’m might get impatient with it and try it tomorrow night.
Here’s a few pictures just because.

mg2361 · May 5, 2026

Did you remove the planetary gear set and replace the seal rings on that? They are also for forward.

wisdumb · May 5, 2026

Yes. They are cast iron rings that snap together. Thank you.

wisdumb · May 10, 2026

so it is now leaking between the case and the front cover housing. Leaking a lot. I removed the reverser put a new gasket and it is still leaking. I am now wondering if this hard rubber like washer that is orange is not supposed to be where I have it causing interference. If that is the case, where does it go?
I believe it’s part number 22 thrust washer on the clutch pack. If it is correct why am I leaking so much fluid?
I am in need of guidance once again.

Thank you and sorry for being a pain in the A**

mg2361 · May 10, 2026

#22 is a thrust washer (a fiber like material) and it is supposed to be there. Are you sure the internal components (planetary and the forward clutch pack) are seated all the way in? All of the reverse brake discs engaged on the splines? Did you reuse the gasket and it got damaged?

wisdumb · May 10, 2026

I used a new gasket from John Deere. Everything to me seems good. The planetary seats all the way in and the forward clutch pack dropped all the way in. It is tricky to seat it in all the way. I took a picture of the last plate that has the springs under it and it is sitting flush with the case. It’s really got me stumped. Could an oil passage be blocked causing it to leak?

wisdumb · May 10, 2026

Yes reverse splines are engaged on the outside teeth of the clutch pack.
I’m about to take it apart again and maybe video me assembling the whole thing and post a link to YouTube and maybe you can see if I’m missing something.

wisdumb · May 13, 2026

So I think I may have had the 2 oil hoses going to the oil cooler switched. Would that put too much pressure in the system and blow my seals?

mg2361 · May 13, 2026

Oil would flow the wrong way through the cooler, not build pressure. Where on the reverser front cover does the oil come out?

John Deere 310C won’t go forward after rebuild, new hydraulic leak.

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