TH400 Shifter Leak?
Safety Car
Joined: Aug 2001
Posts: 3,683
Likes: 201
From: Waterford Mi
Re: TH400 Shifter Leak? (7T9L82)
The seal is removed form the outside without droping the pan. It takes a special tool to remove it. Te shaft should be checked fo rust/ware and replaced if it is. Most trans shops can replace the seal in about a hour. You might be able to do it if you can get the old seal out.
Check the dirp stick tube for leaks. It is right above the shifter shaft. There is an O-ring on the tube that may be rotten. To replace it you will need to unbolt it from the bellhousing where it goes to the motor. Then it will pull out of the hole and you can replace the O-ring.
[Modified by redwingvette, 5:46 PM 2/10/2003]
Check the dirp stick tube for leaks. It is right above the shifter shaft. There is an O-ring on the tube that may be rotten. To replace it you will need to unbolt it from the bellhousing where it goes to the motor. Then it will pull out of the hole and you can replace the O-ring.
[Modified by redwingvette, 5:46 PM 2/10/2003]
Le Mans Master
Joined: Aug 2000
Posts: 9,662
Likes: 7
From: Semper ubi, sub ubi
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: TH400 Shifter Leak? (tzavaleta)
Installing it isn't really hard, the problem comes from getting the old seal out. The seal is a tiny metal seal with a rubber lip. It is only about 5/8" in diameter and slips over the shift shaft into a recess in the case.
The easiest way would be to pry the old one out with a sharp awl, then slip the new one over the shaft and seat it with an appropriately sized 1/4" drive deep socket.
I did mine the hard way, I had the whole tranny out, so I removed the shaft from inside the case then slipped the shaft through the seal from the inside. This is not necessary. In fact I have been told that there is room in front of the old seal to drive in another seal on top of the old one.
Many times replacing the seal won't stop the leak, since the shaft itself is rough from wear and corrosion, then you have to drop the pan and replace the shaft and seal together.
I think this was the problem with mine, since it is leaking again from the shaft seal. Before I drop the pan and replace the seal, I'm going to try and slip another seal over the shaft. Since the new seal will contact the shaft in a different position so if there is wear on the shaft, hopefully it won't be worn where the new seal is.
The easiest way would be to pry the old one out with a sharp awl, then slip the new one over the shaft and seat it with an appropriately sized 1/4" drive deep socket.
I did mine the hard way, I had the whole tranny out, so I removed the shaft from inside the case then slipped the shaft through the seal from the inside. This is not necessary. In fact I have been told that there is room in front of the old seal to drive in another seal on top of the old one.
Many times replacing the seal won't stop the leak, since the shaft itself is rough from wear and corrosion, then you have to drop the pan and replace the shaft and seal together.
I think this was the problem with mine, since it is leaking again from the shaft seal. Before I drop the pan and replace the seal, I'm going to try and slip another seal over the shaft. Since the new seal will contact the shaft in a different position so if there is wear on the shaft, hopefully it won't be worn where the new seal is.
