76 with a leaking auto trans around pan
Thread Starter
Heel & Toe
Joined: Jul 2006
Posts: 18
Likes: 0
76 with a leaking auto trans around pan
I have a 76 sitting in the garage with a leaking pan and speedo cable. I know the bright red glow of the transmission fluid quite well. I am trying to decide if it is worth doing myself or putting in the shop. I lean towards putting it in the shop so that if it should leak again, I can blame them and get it fixed without difficulty. My last repair job on my vette with the radiator was not quite so successful and I had to go back in. Thus my hesitation to tackle this one so soon. I also have little experience with transmissions. Thanks for the advice in advance.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
I have a 76 sitting in the garage with a leaking pan and speedo cable. I know the bright red glow of the transmission fluid quite well. I am trying to decide if it is worth doing myself or putting in the shop. I lean towards putting it in the shop so that if it should leak again, I can blame them and get it fixed without difficulty. My last repair job on my vette with the radiator was not quite so successful and I had to go back in. Thus my hesitation to tackle this one so soon. I also have little experience with transmissions. Thanks for the advice in advance.
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
It's hard to tell where the leak is coming from unless you clean everything and then run the engine and watch for leaks. There is a seal though, (o-ring I believe) on the speedo gear. There are several other seals, of course, and the front one could be leaking with the fluid blowing back across the pan as the car moves.
If you've got the garage space, put the car up on jack stands and spray er down with brake clean real good and then see where the leak appears to be originating. The speedo and pan seals aren't difficult but replacing the one behind the torque converter will mean dropping the tranny.
Safety Car
Joined: Aug 2001
Posts: 3,686
Likes: 202
From: Waterford Mi
I had they same problem with my TH400. If the car sat for more then a couple of weeks, the pan gasket would start to leak. I think it was due to the oil leaking out of the converter until it got above the top of the pan. The seal area had a lot of porosity in it, which made it almost impossible for a gasket to seal. I tried just about everything to stop it but the best I got was maybe a month before it started leaking again. I have changed a lot of trans filters in other cars and never had a problem like this trans gave me. I finally decided to replace the trans and I have not regretted it. Besides, it gave me the reason to go to the Overdrive trans.
Tech Contributor
Joined: Aug 1999
Posts: 15,187
Likes: 4,009
From: Connecticut, USA
I have a couple of leaks from the TH400 pan screws too. I just rebuilt the tranny 1,000 miles ago and may have overtightened the bolts. I'll replace the filter and gasket in the warm weather. I suggest if you do this job buy a B&M drain plug kit, makes futre filter changes a lot easier.
Melting Slicks
Joined: Oct 2005
Posts: 2,114
Likes: 0
From: upstate N.Y.
I Had A 350 Turbo Doing The Same Thing. I Took It To A Shop And Had The Pan Dropped And Oil Changed. This Time I New It Wasnt Me Ended Up With A Rebuilt That Doesnt Have A Leak At All. It Could Be Front Seal. Pump Seal ,torq Converter,anda Number Of Things But This Solved It.
