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Discussion Starter #1
I am in process of rebuilding my 67 duetto transmission by swapping out good components out of a large collection of parts transmissions. In the shop manual it shows that the 1st gear syncro assembly has deferent components then 2nd through 5th. why was this done at the factory? Will it still shift properly with the other type of syncro assembly?
 

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Trained (ex)Professional, , 1953-2018 RIP,
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Please read this thread which details the how and why of modifying the first gear syncro.

Please be aware in 67-68 was the time Alfa switched from non-moly components to moly components. My understanding is that parts from these gearboxes are NOT interchangeable. Someone with more experience/knowledge in this area than I (AlfaR7 perhaps?) should pipe in with more details.
 

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Osso - read the thread "First Gear Fix". The differences in the first gear parts causes one of the most irritating characteristics of Alfa's otherwise wonderful transmission design.

Be especially sure to pull the dog teeth parts off the 1st and 2nd gears, which wear badly (and maybe others) and use the best ones you can get from a 4th or 5th gear.

Also look over RJR's (Richard Jameson at RJ Racing in Florida, also known as AlfaR7 here) comments on what the best synchro rings and sliders are. If you have a good selection of the older parts, you are in heaven!

Robert

BTW - we had another user with this same handle, from Colorado on the BB for quite a while.
 

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Discussion Starter #4 (Edited)
I have already machined a tool that clamps the syncro crown ring, or (dog teeth) in order to remove them without damaging them or the gears in the press. I have a lot of spare parts syncro rings, sleeves, and the dog teeth. My original plan was to swap out all the dog teeth, syncro sleeves and rings, including 1st but was unsure of the reason why 1st was different from the factory.

Would like to post pictures of the special tool but all i get is a small blue box with a ? in it..
 

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Richard Jemison
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Trans parts

Please be aware in 67-68 was the time Alfa switched from non-moly components to moly components. My understanding is that parts from these gearboxes are NOT interchangeable. Someone with more experience/knowledge in this area than I (AlfaR7 perhaps?) should pipe in with more details.
The trans will be far nicer to drive loosing the OE 1st gear one directional syncroniser.

If you have good early non- moly dog teeth/syncro receivers to replace 1st and 2nd with (2 receivers, 2 syncro bands, 1 slider ring and 4 friction straps) then use them on these two gears. The band are far more durable, but tooth angles are different from later syncros. That and the internal design are the incompatable part of the different syncros.
The earlier slider rings with an internal machined groove are not as hard/durable material as the later ones. But then the later Moly bands are not as durable as the early bands/ The sliders must match the dog tooth design of both syncros they engage. The bands don`t seem to matter.
With that said on My race trans I use the early non-molly harder syncro bands (harder/more durable) on 2nd, 3rd & 4th with late sliders and dog teeth. With Redline75-90 NS you can mix components (early bands & late bands in a gearbox with no worries on lube compatability)
It should be used in all Alfa trans/transaxles and LSD diffs.
 

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Discussion Starter #6
All the components i am going to be using are out of 1970s transmissions and I'm going to be using Geotze syncro rings that are still in very good shape.
 
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