early transmission main shaft shim question

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just me
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early transmission main shaft shim question

Post by just me »

Attempting the assembly of my early synchro box and measuring and fitting the main shaft assembly. The spec in the manual is .040-.100 clearance between 3rd gear and stop ring. In order to make the middle of that range I need a shim that is .110 at the rear of the main shaft in front of the bearing. This seems excessive to me. Does this jibe with others experience or did I miss something?
"It may be ugly, but at least it is slow!"
ashyers
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Re: early transmission main shaft shim question

Post by ashyers »

I'll need to check my notes, but here's what I remember:
We had more than 1/4" clearance with the orig. synchro assembly.
We replaced the synchro assembly with the new ones from VPW.
I believe I ended up with one .015 shim.

It seems that the synchros have a large effect on the shimming. I'm sure some of this is wear, but our orig. synchros were different in material and design than the new ones. I will say that the loosey goosey synchros we removed worked better than the new ones and we shot for the low end of the range when we shimmed the box.
just me
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Re: early transmission main shaft shim question

Post by just me »

I have the same conclusion as you, Andy. New synchro inner and outer stop rings and I didn't even need a shim. I'm at .043" clearance. Will have to see if it shifts! Just putting the finishing touches on the shifter top and the modifications and waiting on 1 part to finish the PTO. Should be done this weekend with entire drive package if I assemble a carburetor this week, also.
Then, to pull the old power unit and put this new one in.
"It may be ugly, but at least it is slow!"
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