Transmission parts question Options

[targa72e]

I was going thru my stash of transmission parts and picking parts to use for future build. I found that I had 3 synchronize blocks that were slightly different.

Most of the blocks have a triangle on top.


But 3 have a triangle on the side



The ones with triangles on side are also a slightly different shape. Instead of the protrusion being square it is slightly angled.


Is there any advantage/disadvantage to this type of block?

In looking at intermediate plates I have one that is thinner with a different bearing mount with only 4 bolts. Any idea what this is from?




Thanks,

john

[oldie914]

Looks like your intermediate plate is for a 901 aluminum case transmission. Thinner than the plate for the magnesium 911 and 914 cases.

[targa72e]

Thanks for the identification of the intermediate plate.

john

[oldie914]

I looked through my cans of 914 and 914 syncro parts. I try to keep them separated because Porsche stopped developement of the 911 transmission when they switched to the 915, while VW continued to made detail changes to some of the parts that are hard to see.
That said; the blocks in my 911 can were shaped like your 3 strays. The blocks in my 914 can were shaped like the majority of your blocks. Both should work OK.

[targa72e]

Thanks for the reply. That got my looking at what is currently being sold as a replacement. Looking at a couple sites they had the same part listed for 911 and 914. All the new parts listed are the shape of my 3 strangers. I am curious if there is any advantage to this style?

Thanks,

john

[oldie914]

I don't think there is any difference in function of the 2 different blocks.
VW did make a change in the shape of the other block and the brake bands though which is important.
I have attached pictures of the syncro parts for a 914 gear (left) and a 901 gear (right). Don't know the year for the 914 gear but the 901 gear was manufactured in September 1969. VW probably used the 901 style block in early production and changed later.
I have never seen a problem with the early blocks, but there I have seen discussion about broken early style blocks. Would probably only happen on 2nd or 3rd gear with very hard usage.

[targa72e]

Thanks, I was aware of the early and late style blocks and bands. The later style with larger lower block is supposed to be better from what I have read. I have both styles in my stash and was picking the best of the late style larger units to use in a future transmission. That is when I found the three upper blocks that have a different shape that started this thread.

john