th400 speedometer cable leak
 

Have the car up on jackstands right now and I've found that the place where the tranny leaks most is from the speedometer cable. Now I wonder if there's anything special I should think about before I start. The transmission is still in the car btw.

I suppose there is some kind of gearwheels behind the cover, anything special I should think about when I take the parts apart and put them together again?

I've searched the archives but found nothing detailed about changing these gaskets.

Re: th400 speedometer cable leak (Larsson)
 

I can check the th400 I have but the Muncie and ST-10 trannies use a O ring on the sleeve for the speedo gear in the housing. I think the TH400 is the same too?
Gary

Re: th400 speedometer cable leak (gtr1999)
 

There is an O-ring on the sleeve and a seal on the inside that rides on the gear. Both parts can be found at most parts stores. You will want to check the gear for wear as well. Any grooves in it will cause it to leak.

Re: th400 speedometer cable leak (redwingvette)
 

THe gear can wear the "sleeve"that it goes through. Make sure the hole is not oblong and the gear fit is not loose.