B20-Leaking transmission input seal

[Schweers]

Hello Looking for some advice,

Have a 1996 B20 with TL420 loader and BT750 B/H. Noticed an oil leak was present when machine was running. Removed cover and checked with mirror and found oil was coming from the shaft seal. Seperated the tractor and changed out the seal (66363-3949-0) also found some wear on the shaft and installed a speedi-sleeve to be sure. Reassembled the tractor and operated for roughly ten hours leak free. Then noticed oil is now weeping from this seal again. Checked the case relief pressure and found it was OK, also checked the charge valve and relief valves and found they were all ok. Case pressure was 13psi at idle with warm oil and went to 30psi at high idle. (pressure is within spec (14-43psi). Is there any thing else in the system that would cause excessive pressure on this input seal? It is a large job to seperate this machine and its pretty disappointing to do all this work and see it fail in such a short time. Is there anything else I could check, or something I am missing, that might of caused this seal to fail again so rapidly? I have owned the machine for about five years and did not have any issues with this until last year. Thx

 

[mickeyd]

Welcome to the forum. I know that this must be very frustrating.

 

[North Idaho Wolfman]

The seal your referring to is #490, I don't think the speedy sleeve was a good idea, kind of a Band-Aid on a knife wound, if there is wear on the shaft I would have just replaced it.
Also if there is any wear on bearing #20 it will cause the seal to fail.
I would say your going to have to tear it back down and go deeper.

 

[Schweers]

The seal your referring to is #490, I don't think the speedy sleeve was a good idea, kind of a Band-Aid on a knife wound, if there is wear on the shaft I would have just replaced it.
Also if there is any wear on bearing #20 it will cause the seal to fail.
I would say your going to have to tear it back down and go deeper.

Thanks Wolfman,

I will look into this further sometime in the near future (machine is still running fine just losing a small amount of oil). One other thing I forgot to mention was the seal would also weep even when the clutch pedal is fully depressed (input shaft not turning). It also seems to leak more when idling then when operated at high idle? I had checked the input bearing before I replaced the seal and it appeared very tight, also cut the filter open and inspected it and found the media was very clean. The shaft had a very slight groove on the sealing surface and I installed the sleeve just to be sure. All the trans pressures are in spec according to the service manual. I am unsure of the exact hours on the machine before I got it (the tach cable was broken). Does the input seal hold back case pressure or is it splash oil. Also if I have to pull the transmission how long does it usually take to remove it? Thanks for your help

 

[Tooljunkie]

Ok.looks like wolfman nailed it again. Let me run this by you- an additive that softens seals. It is an effective treatment if a stiff seal is the issue. I know it works,just poured a bottle into a ford Ranger 4 litre engine that was using a litre to a tank of gas. Four tanks and no oil added. Up here its 23.00 a bottle. To the skeptics,its a small price to pay if it works.
ATP AT205 transmission reseal.

Worst case-you have to pull it apart again.