Can the GM turbo400 transmission be removed without pulling the engine?

[Jim S]

My transmission in my 72 Avanti is leaking badly in the front.  I see several drops of fluid coming out of the small hole at the botton of the bellhousing cover.  I had two transmission mechanics tell me the front seals on those trannies seldom go out.   My front seal and the front pump bushing  was replaced  just a few months  ago. Yet it's leaking again badly! It was very difficult for this 70 year old to pull just the engine a few months ago and I really don't want to do it again.  I want a shop to do it, so again my question is can they just drop the trannie clear of the X frame.  Or do they have to pull the engine?  Never have I had a  more troublesome car than the two GM power train Avantis.  If I can get this thing fixed and sold, I am going back to pure Studebaker!!

[mfg]

2 hours ago, Jim S said:

My transmission in my 72 Avanti is leaking badly in the front.  I see several drops of fluid coming out of the small hole at the botton of the bellhousing cover.  I had two transmission mechanics tell me the front seals on those trannies seldom go out.   My front seal and the front pump bushing  was replaced  just a few months  ago. Yet it's leaking again badly! It was very difficult for this 70 year old to pull just the engine a few months ago and I really don't want to do it again.  I want a shop to do it, so again my question is can they just drop the trannie clear of the X frame.  Or do they have to pull the engine?  Never have I had a  more troublesome car than the two GM power train Avantis.  If I can get this thing fixed and sold, I am going back to pure Studebaker!!

Yes,  the trans can definitely be removed without removing the engine/trans assy… but availability of a twin post lift would sure make the job easier!

[Jim S]

Thank you for the info. I will have a reputable trans.shop doing the work. They should be able to handle it. 

[Kevin G.]

That seal had to have been put in wrong before, as they rarely leak, the TH400 Trans is one of the most bullet-proof transmissions ever made; they put them on GM motor homes back in the day; be sure they put in a new solenoid on the shifting module, as that is inside the transmission and 'messy to change later and the new style works a lot better than the old copper-colil one. 

[Jim S]

The seal was installed properly, however a local trans mechanic just told me if the torque convertor neck is badly worn, they will certainly leak. That may be my problem. It’s going in the shop next week. And hopefully we’ll find the culprit. 

[Adam DeRosa]

The transmission can definitely be removed from below without removing the engine. The exhaust pipes might be in the way though and might need to be disconnected at the manifolds and moved for clearance.  

[Jim S]

I thought so too.  They are very close to the transmission.  It looks like you can remove the rear mount support plate at the center of the "X" frame and drop it out.

[Jim S]

Great news!  I finally found a good shop in my area willing to tackle the removal of my transmission.  They had to cut a section of the right side exhaust pipe for clearance, but got it out.  The torque convertor snout was worn and causing premature wear on the front seal and the pump bushing.  Hopefully a new convertor and seals will finally stop all the leakage!

[mfg]

7 minutes ago, Jim S said:

Great news!  I finally found a good shop in my area willing to tackle the removal of my transmission.  They had to cut a section of the right side exhaust pipe for clearance, but got it out.  The torque convertor snout was worn and causing premature wear on the front seal and the pump bushing.  Hopefully a new convertor and seals will finally stop all the leakage!

Great news Jim!!