German 4 speed Transmission

Having problem with the tail shaft seal leaking in our transmission. When the car is sitting in the shop it will leak app. 2oz. when running at the track we do not see any signs of leakage. In the past 3 months have changed the seal 3 times. I use a National seal #2443. The yoke has been checked and mics right. Have been using this type of transmission for 17 years never had this problem. we have another car with the same type trans., yoke, seal, and fluid but it does not leak. Anybody have any problems like this or have any suggestions.

TC65

Is the vent open on the top plate? Can you tell if it is leaking between the yoke and the seal or could it be leaking between the seal mounting surface and the tail housing? How about the oil leaking out the back of the yoke next to the u-joint. If I'm not mistaken there is a plug at the back of the yoke like a frost plug. I have seen them leak there. Just a few ideas.

No groove in the output shaft?

It is leaking between the yoke and the seal. I have checked yoke for scratches etc. found nothing. the yoke measures about .003 larger than the seal. The vent is open on plate. Have changed the plate.

Thanks
TC65

is the spring still on the seal, or is it coming off when you knock the seal in. pack the groove on the seal with wheel bearing grease before you knock the seal in, the grease keeps the spring from popping out.

Check to see if the bushing the yoke rides in is worn. That will cause the seal to leak.

u joint bad?

1195 I think and hope you are right. I have a 80 Ford tech and it says to inspect this bushing when changing the seal. I have a tail shaft that is off another trans. and I removed the seal in it and the bushing is easy to see. The bushing is about 2 inches or so long and I can feel an edge around it. I am going to see if I can find a tool to remove the one in the spare tail shaft.

Thanks to everyone
TC65

Ya checking the bushing is a good idea. Best way would be with the seal out, then slide the joke in and see how much play there is by rocking the yoke up and down. Much easier with the seal out. Swoping tail housings isn't as easy as it looks. If you have to change the bushing you can probably split the bushing with the tail housing still on the trans and pick it out.

Could be leaking out of the back of the yoke . It has a seal like a freeze plug but flat . Try to clean it with carb cleaner and put silicone around it .

Quote:

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Originally Posted by hatchet

Could be leaking out of the back of the yoke . It has a seal like a freeze plug but flat . Try to clean it with carb cleaner and put silicone around it .

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Uh, I think Foghorn already suggested that. After that the person having the problem said he thinks it is leaking between the yoke and the seal.