I heard back from the guy I contracted to build a toploader for me. We had to wait for the builder to return to the area to take apart and inspect the trans. I was informed that first gear is “welded” to the mainshaft and that only two likely scenarios could have caused that to happen.
One is there was little or no oil in the trans and two I must have wound the engine up to 7K in first gear. Neither of those things happened. So I’m back to looking for suggestions from you guys as to what likely happened. I got less than ten miles of easy driving around town before the trans blew. It had two quarts of Driven 80/90 GL-4 oil in it. The main case split at about 4500 rpms in third. I managed to get it into first as I was trying to get the car into my yard.
Could first gear be stuck on the mainshaft due to the time the trans ran dry before I got the car in the yard? The total distance from the explosion to my yard was less than 1800 ft.
Every second counts