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Discussion Starter #1
Hi Everyone...

I had rebuilt my transmission ~6months ago on my 71 spider. In general a new-used 2nd dog gear/synchro sleeve, new 5th/rev fork, moved some other dog gears around, and finally 5 new Alfaholics synchro rings. Last week I took the car out and it wouldn't go into 5th. Pulled the transmission and where you can slightly rotate the synchros for 1st-4th, the 5th gear one wouldn't move. I'm assuming since it jammed it couldn't slight compress when the synchro sleeve goes over it preventing the sleeve from engaging the dog gear. So I pulled the gear, removed the retainer ring, and once removed, everything seems to move ok. As you can imagine I'm hesitant to put it make together until I know why it jammed. Only thing I note is the retaining ring isn't flat...ie mushroomed type of shape and you can see a little wear on the outer edge. Did this allow just a little axial (shaft dir) motion? Any ideas or other things to check?
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Did you purchase the Alfaholics 5-R fork? Did it have serrations at the attaching point to the selector rod?
 

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I don’t see a relief in the bushing where the oil access cutouts are, but that’s not the cause. The smalll T in the synchro looks very odd, did it jam preventing the ring from rotating? Check the dimensions and the dog ring dimensions there.
 

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Discussion Starter #4
Hi Andy... yes, the fork had serrations and it's spacing was set to that 10mm dimension...

Hi Goats... bushing comment.... if I understand what your comment, remember 5th rides on needle bearings so no bushing or oiling hole. Yes the "T" is in roughly the position it was when I took it apart. If I rotate the it goes thru the neutral position and then to the other side...
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Richard Jemison
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"Moving the other dog gears around"

The brake bands in the syncros are the same other than 1st which only has 1 long band, as it is a 1 directional syncro. Read the Sticky" on this in the transmission area of the BB. If you discard the long band and engagement slider and use 2nd through engagement slider and the 2nd-5th brake bands installed correctly it will work fine.

However if you install the bands and in the process a brake band gets between the thick slider and the syncro ring then the syncro ring cannot be compresses and the slider will be blocked from engaging the gear.


Removing the gears in the 5th/reverse group can be done without dissembling the two pice primary case. But you have to have prior to assembling, ground a small rounded groove on the edges of the slider where the fork rides. It only needs to be about 1/8 inch deep and does not effect slider function.

This allows 5th gear (ratio) changes. I do this in all my CR racing transmissions.
 

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Discussion Starter #6
Hi Richard... yep, in the process of "moving dog gears around" one goal was to swap out the 1st gear dog gear with one from 2-5th that takes the bi-directional two band version shown in a number of posts. Great info here...

I think your description of how it was blocked is spot on but I believe it was assembled correctly as 5th worked for many months. So what happened to allow it to get between those parts? Is there some tolerancing issue? Would you replace the bands/"T"s to be safe?
 

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Is it possible you swapped the original first gear band into 5th? The first year band is shorter than the other 8.
 

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Discussion Starter #8
Hi goats... I can't say for sure. But comparing the two in there now they seem the same. Maybe the new-old ones I got to replace the single 1st gear one weren't actually from 2-5th, but two 1st gear ones, and I put them in this 5th? Anyone have a measurement of one to check?
 
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