C2 M20 downshifting problem

[Grant M.]

Can anyone suggest the speed range at which downshifting from second to first should be able to be done (without double-clutching) on a (1965) M20? the transmission has just been professionally rebuilt and on initial drives, downshifts around 15 mph or so were no problem, and then, after re-installing the console, it now grinds and won't go into gear when trying to downshift to first, except at very low speeds, ie: 1-2 mph. Shifting into first from a start is no issue; the transmission is smooth and noise and vibration-free.

Thanks for any advice,

Grant

[Mel S.]

Re: C2 M20 downshifting problem

sounds like you have a stuck or broken syncro ring.
Mel

[Grant M.]

Re: C2 M20 downshifting problem

That was kind of what I thought. Car's going back to the transmission shop in the morning (3 1/2 hrs on a trailer).

Thanks,

Grant

[Joe L.]

Re: C2 M20 downshifting problem

That was kind of what I thought. Car's going back to the transmission shop in the morning (3 1/2 hrs on a trailer).

Thanks,

Grant

Grant-------


The only brass synchro (blocking) rings that I have ever found that work absolutely correctly are the ORIGINAL GM rings. Even the GM replacement rings (6 digit part numbers) are not as good as the originals. I highly doubt that your transmission shop will have any of even the GM replacements, let alone the originals.

[James W.]

Re: C2 M20 downshifting problem

Joe,

What is the correct GM part number that would be a good replacement if they could be located?

James

Grant-------


The only brass synchro (blocking) rings that I have ever found that work absolutely correctly are the ORIGINAL GM rings. Even the GM replacement rings (6 digit part numbers) are not as good as the originals. I highly doubt that your transmission shop will have any of even the GM replacements, let alone the originals.

[Joe L.]

Re: C2 M20 downshifting problem

Joe,

What is the correct GM part number that would be a good replacement if they could be located?

James

James-------


Well, I'm in Italy right now so I do not have my references available and I just don't have these particular part numbers committed to memory.