I'm new here, so any help is appreciated.
I've just finished rebuilding a 1964 t100 motor and am having a hell of a time getting the gearbox back into the case. Seems like the lay shaft and shifter spindle don't want to seat. Any tricks?
I know when I put the transmission in my '70 T100, it acts as if it doesn't want to seat at first and it usually just needs some persuasion. There's that spring-loaded selector detent in the back of the gearbox case and I always feel that is what's keeping it from going. I can usually get it to seat, but it 'pops' back out. I just tap it in there and spin a screw in it to keep it there while i torque it.
Okay, I figured this out.
I'm going to post it here in case anyone else makes the same mistake I did.
I've got two 1964 t100 motors. I've been stealing some good parts from one to replace worn out parts on the other. One of the motors is a t100sc and the other is a t100sr, both pre-1968. I took a mainshaft second gear from the t100sr gearbox and used it on the t100sc gearbox. They both looked the same and it seemed to fit no problem; I assumed the two gearboxes were the same. After doing trial and error for hours, trying to figure out what it was that was preventing the gearbox from seating, I narrowed the problem down to the layshaft not aligning properly with the bearing in the case. The only thing that would allow it to align properly was when I removed the second gear from the mainshaft. Upon closer inspection, I realized they are actually two different gears with different part numbers. I guess the corresponding layshaft gear would have been a different gear on the t100sr motor as well. Because I didn't change both, the new t100sr gear must have forced the layshaft slightly out of alignment.
So... I put the original gear back in and it all went together fine. From now on I'll be more dilligent about checking part numbers when swapping things that appear compatible.
Hopefully this helps somebody else out there experiencing a similar problem.
Thanks for the update. I think taking stuff for granted that turns out to be wrong is one of my most common errors. Sometimes "thinking like a mechanic" means going back to the beginning and eliminating every possible issue, but it is very easy to overlook something you have taken for granted, wrongly.
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