1980 4-Speed Trans Mount Bolt Sizes
Thread Starter
Racer
Joined: Jul 2017
Posts: 364
Likes: 103
From: Atlanta
1980 4-Speed Trans Mount Bolt Sizes
I am having an issue with replacing my trans mount. What size are the threaded holes in the transmission where the mount bolts to it on a 1980 4 speed?
I had trouble getting the old bolts out. There was tension on the bolt all the way until I got it out despite thee being no reason. I figured the PO cross threaded the bolts because one of them was pretty galled up. I am also unable to run a standard die over the threads of those bolts cleanly.
I have two new bolt kits, but one has 7/16-14x1 1/4 bolts, and the other has 3/8-16x3/4...
So, which should be correct? Hopefully I don't need to tap new threads...
I had trouble getting the old bolts out. There was tension on the bolt all the way until I got it out despite thee being no reason. I figured the PO cross threaded the bolts because one of them was pretty galled up. I am also unable to run a standard die over the threads of those bolts cleanly.
I have two new bolt kits, but one has 7/16-14x1 1/4 bolts, and the other has 3/8-16x3/4...
So, which should be correct? Hopefully I don't need to tap new threads...
Last edited by Black72GTS; May 20, 2020 at 02:41 PM.
NCM Grand Opening Veteran
Joined: Sep 2005
Posts: 20,979
Likes: 384
From: South of giving a damn
St. Jude Donor '11, '17
If the bolts galled on the way out then the threads are probably unrecoverable in that aluminum case.
Worst case you can drill out the case and helicoil it
Worst case you can drill out the case and helicoil it
