2/3shifter fork id 1938 3speed

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primerking

Junior Member
Hi
I have trouble with neutral alignment on my gearbox . It is a 78series case with the 48-7106 syncro and 81a-7222 double detent tower with 68-7231 low/rev shift fork and a shift fork for 2/high marked only with «32»
I have changed the syncro since it the bronze bushin on the main shaft side was gone. The rest of the gearbox is overhauled using the books from VanPelt/Tardel
When i put the shift tower on in neutral the shifter are ca 2-3 mm of center when i align the bolt holes. I read in the green book that i should have the 68-7230 shift fork but i cant find the number(its 2.81’’ between the tips same as the one i have)
Is it possible that i have the older typ fork to the slant tower and that pushes it off center? Other than that i cant find anything wrong.

Any help is appreciated

Jon
 

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The 48 syncro should move freely on the main shaft fore and aft about 1/4" so alignment of the shift tower fingers should not be a problem.
 
primerking said:
Hi
I have trouble with neutral alignment on my gearbox . It is a 78series case with the 48-7106 syncro and 81a-7222 double detent tower with 68-7231 low/rev shift fork and a shift fork for 2/high marked only with «32»
I have changed the syncro since it the bronze bushin on the main shaft side was gone. The rest of the gearbox is overhauled using the books from VanPelt/Tardel
When i put the shift tower on in neutral the shifter are ca 2-3 mm of center when i align the bolt holes. I read in the green book that i should have the 68-7230 shift fork but i cant find the number(its 2.81’’ between the tips same as the one i have)
Is it possible that i have the older typ fork to the slant tower and that pushes it off center? Other than that i cant find anything wrong.

Any help is appreciated

Jon
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I'm wondering if you have the right synchro assembly for this setup? On the later top-loader transmissions, the syncho hub groove is toward the back of the collar. I can't tell for sure, but it looks like you have the earlier synchro slider/collar - where the groove is centered in the middle? I would check Van-Pelt's site and maybe call Mac and make sure you have the right combination of parts.
 
Give Mac VP a call. He may know more than I could add. It could be the 1st gen 2/3 synchro sleeve or shift fork.
 
Bored&Stroked said:
I'm wondering if you have the right synchro assembly for this setup? On the later top-loader transmissions, the syncho hub groove is toward the back of the collar. I can't tell for sure, but it looks like you have the earlier synchro slider/collar - where the groove is centered in the middle? I would check Van-Pelt's site and maybe call Mac and make sure you have the right combination of parts.
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Thinking the same thing, Dale.
 
Here is a tech article on setting the second gear thrust. While it shows a minimum of .004, I prefer to achieve a .003 clearance.

Transmission Spacer_2ndThrust.jpg
 
I measured the free movement and placed the hub in center and the lid popped right on and the boltholes aligned, i have done this several times before with 2-3 mm of center but suddenly everything is okay. The reason i began to worry was that the maindrive rotated in neutral and the trans overheated. I took it apart and the needle bearing between the shaft had turned in the cage due to amissing bolt in the uni joint so the shaft moved in the bearing.
 
I will post a update when i have put everything back together. Most of the info in books and tech articles is about the more modern real syncro, i have not found so much about the early 39 type regarding shimming etc. i have changed the bearing on the 2 gear so now its good but i think the shimming in the post over is for the new type.
Thanks
Jon
 
Pictures of the syncro in 2-3
 

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The last picture are from the old syncro hub that wire out because of the missing bolt. There was not a bolt there when i took it apart so i put it toghether without a bolt so now i have to do it all over again. This time with the bolt in place, learning a little everything day:)
 
primerking said:
I will post a update when i have put everything back together. Most of the info in books and tech articles is about the more modern real syncro, i have not found so much about the early 39 type regarding shimming etc. i have changed the bearing on the 2 gear so now its good but i think the shimming in the post over is for the new type.
Thanks
Jon
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The .004 to .008" applies to 1932 through 1947
 
Thank you for the link and info about clearance, the changing of the internal bushing helped a lot on the clearance but i will check again when i reassemble. I think its a little more than what you described in mine. I have to check what kind of shims i need. The bolt i was referring to was the one with a thick spacer that holds the uni joint to the main drive shaft. There is no lock ring that holds the shaft like that on the main shaft.
 
Can’t tell from pics - is that a straight or slanted tower? Sorry, just read your original post which says 81A double detent tower…
 
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