915 1st Gear Symmetrical vs. Asymmetrical Synchro Hub

[Jim Sims]

We've taken apart all the synchros in a late year '73 5 speed 915. All the synchro hub teeth appear sharp. All sychro rings show friction surface wear on side towards operating sleeve and on other surfaces. Brake bands from 1st and 2nd synchros show wear. 1/2 & 3/4 operating sleeves (sliders) look like they warrant replacing. I am aware of the change (in 1977?) from the symmetrical to asymmetrical first gear synchro hub and matching operating sleeve. It also appears the thrust block (energizer), brake bands and anchor block were changed with the anchor block being changed twice during that year.

This is my 1st QUESTION: If the original (pre 1977) first gear dog teeth on the symmetrical synchro hub are okay then is it possible to obtain a new matching 1/2 operating sleeve (slider )and 1st and 2nd gear brake bands?

This is my 2nd QUESTION: If we need to go this way and upgrade to the 1st gear asymmetrical synchro hub; what do the asymmetrical upgrade kits contain? I am asumming a 1/2 operating sleeve with asymmetrical teeth for the 1st gear side; the 2 brake bands (there appear to be 2 in the upgraded configuration) for 1st and a new thrust block and anchor block for 1st.

Thanks for your help!

Jim and Brad

[tbitz]

Jim,

I don't have answers to your questions, but Pelican sells the upgrade kit. I'm sure they (Wayne) would be more than happy to tell you what is included.

Check the syncho hub section of the link below. It talks about the upgrade kit.

http://www.pelicanparts.com/catalog/shopcart/911M/por_911M_tranny_main.htm