Today we look into the proper set up and adjustment of the late model Corvair manual transmission shifter, a topic that is often misunderstood. “What’s so hard about a shifter?” quips Ralphie in the back row.
Well, aside from the usual fore -aft adjustment of the shift rod to the shift coupler, the late model shifter itself is a floating mount, unlike the early Corvair which simply bolted the shifter tight to the floor. With the early design, any fore-aft movement of the powertrain will cause the shift lever (more specifically the position of the hand operated shifter knob) to move a much greater amount as it is some 12″ higher than the pivot point in the shifter base. And, with both the powertrain and rear suspention crossmember held to the body with rubber mounts or bushings, there will be some movement under harsh bumps or sudden acceleration/braking action (yes, I’m looking at you Mr. Rallyist /autocrosser/drag racer).
The late model shifter sought to correct the issue of shift lever movement by allowing the shifter base to move fore/aft with the powertrain, so 1/4″ of movement in the powertain would still be just a 1/4″ of movement at the shifter knob, unlike the early model which would multiply the movement significantly at the knob.
To make this work, the shifter bolt mounting holes in the floor of late models are slots, not just round holes. The shift rod running from the shifter to the transmission has a companion outer tube that runs from the base of the shifter to the end of the underbody “control tunnel”; a short rod then connects the end of that tube to the transmission mounting bracket. The shifter itself does not bolt tightly to the floor; instead there are rectangular plastic plates (Chevy called it a seal) both above and below the floor that allow the entire shifter base and the outer shift tube to slide fore & aft. There were diferent thicknesses of the plastic “seals” as well as a steel shim(s) to gain the desired minimum clearence that would let the shifter assembly be able to move fore-aft with the powertrain, but not have any noticeable looseness to the floor itself.
So yeah Ralphie, “fixing’ the shifter was no longer a ‘quick’ fix as it had been on the earlies, thus this service bulletin to help the techs get it right.
In todays’s Corvair world, we are fortunate that Clarks has reproduced all the plastic “seals” and shims, plus bushings to rebuild the outer shift tube and the coupler to renew the inner shift tube. But don’t think you’ll get that all done- or even *just* reshimming the shift base-in the .4 hour flat rate time given for the job!
Another look back into Corvair history from the Corvair Historical Society!
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