1965 4-Speed Shifting Problem

[Tim Genovese]

I am having difficulty downshifting into 2nd gear with my '65 396.

The only way I am able to downshift into 2nd is to move the shifter towards 1st and then drop it into 2nd. The only time I experience the problem with 2nd gear is when I downshift. The clutch appears to be good.

What do you think?

Shifter?

Transmission?

Thanks.

[John]

Re: 1965 4-Speed Shifting Problem

Sounds like a linkage adjustment is in order; you're not having a problem when upshifting from 1st, as the 1-2 upshift only involves one lever at the shifter and one at the transmission side cover. You're having a 3-2 downshift problem because the 3-4 lever at the side cover isn't in its seated neutral position when you come out of third, which prevents motion of the 1-2 lever unless you fiddle with it (moving toward 1st in order to get it to move back toward second). Could also be caused by lots of wear on the shift fork pads where they engage the synchros or wear in the grooves on the synchro hubs.

[G B.]

Here's what I did.

I had exactly the same problem with the original M-21 in my '69. This car is an old 427/435 drag car.

I fixed the problem by installing a new 1-2 slider and second gear snychronizer ring. The engagement teeth had lost their points on the old slider.

I think moving the shifter towards first gear before downshifting into second had been giving the slider a "running start" and the momentum to engage second gear. With the new slider, a running start isn't necessary.

[William C.]

Re: 1965 4-Speed Shifting Problem

Unfortunately, I have to agree with Jerry, at least to a point. The problem when downshifting is that the brass ring in the synchro has to act as a clutch to speed up the gearset in the trans. This is a much more difficult proposition than slowing the gearset down which is the normal function of the brass (blocking0 ring during upshifting. When the ring begins to wear, the fist thing you lose is the downshift capability. Pushing the shifter toward first uses the low speed blocking ring to perform the speedup of the gearset, which makes less work for the second gear ring when you engage second. At minimum, you need a new blocking ring. Only inspection after disassembly will tell if a slider and other parts are needed. If the whole assembly is to be replaced in a '65, you can use the 66-74 syncronizer as long as the complete assembly including the hub and blocking rings are exchanged with the later parts. 63-65 synchro's used different hubs and blocking rings than the later 66-up units and the brass rings cannot be exchanged without changing the hubs also. If you change the hubs, the later style blocker rings are less prone to wear. If you have any specific questions, please e-mail me & I'll try to help. (all the above assumes you have an original '65 trans, identifiable by the casting # on the side of the maincase ending in "325"