Replacing TH400 torque converter seal?

[ClydesdaleKevin]

Hey guys.  Has anyone ever replaced the torque converter seal on your TH400 transmission?  It looks like it can be done without removing the transmission all the way...but do I have to remove the torque converter from the backing plate, or can I leave it there and pull the transmission back just enough to clear the input shaft? 


Kev

[Rickf1985]

Torque convertor will have to come out completely since the seal is a round seal and has to go over the input shafts. I know you do not want to hear this but something to consider is that unless that seal is hard from heat then there is a good chance the convertor bushing may be worn allowing the convertor to wobble. If the seal is hard then the rest of the seals in the transmission probably are also and could let you down on the road.


After reading you post again I see that you are planning on clearing the input shafts but I would definitely take the convertor off the flywheel to reinstall or you risk doing a lot of damage to the pump. There are two steps you need to get over in there so you have to turn it a bit back and forth to line up splines and dogs. ( no, not those dogs )


If the seal is still soft then replace and hope for the best, if it is hard replace and plan on rebuilding the transmission once you get to your wintering grounds. This is the absolute easiest transmission out there to rebuild and with the care you give it you probably would only need clutches and seals. And gaskets of coarse. I think those kits are around 100.00.

[ClydesdaleKevin]

Less than 4 quarts came out when I drained it, so I think I got lucky.  I pretty much ruled out the torque converter seal, which would only leak if the engine was running.  Gotta be the pan gasket, or maybe even the vacuum actuator o-ring.  I'll be replacing the gasket tomorrow, as well as the actuator and o-ring.

Kev