Shifter base shims

[PHX65CorsaHT]

What has been your experience with the number of shims needed above and below floor at shifter base? My car has only one top and one bottom. The four bolts of course will not go tight. Creates somewhat sloppy shifter and may be contributing to my car not going into 3 or 4th gear. I am thinking about making my own out of plexiglass with possibly some thin rubber (like bicycle tube type) for a bit of vibration dampening. Does this sound like a good idea or should I stick with the thin plastic shims and stack them? Thoughts and experiences greatly appreciated, thanks.

[terribleted]

You might need more shim, but the shimming does little to the actual available shifting movement. More likely causes are wear or adjustment at the shift coupler and pin to teh trans nub. The hole where the pin goes through the coupler should be round and a snug fit to the pin. Also look at the big rivet (or bolt) that joins the fat part of the coupler to the rod part that goes into the shift tube (should not have any rotational slop). How is the rubber inside the coupler?? Replace coupler and pin to trans nub if wear is present.

The couplers have some sideways slop which can be adjusted where the coupler clamps in the tube. If 3rd and 4th are the problem you need to loosten the clamp and rotate the coupler in the tube a bit more counterclockwis (I think is counterclockwise anyway it needs to rotate farther toward 3 and 4). Hope this helps.

[PHX65CorsaHT]

Terribleted, thanks. I will try the rotation at the coupler this week and report back. Also, thinking about doing the pvc pipe modification inside the tube. Have you tried this, is the effort to do this worth it? Thanks again the 3 and 4 gear thing really buggin since I have a new 140 in it now and cant really test it with 2 gears!

[MonzaDave]

The shifter base is intended to be able to move a bit fore and aft (hence the slotted holes in the shims), but it shouldn't feel loose. Note that there are "shoulders" on the shifter base that limit how far you can tighten the nuts holding the base in place. The number of shims required for a specific car are determined by a measurement of the sheet metal thickness where the shifter mounts. See Clark's catalog or the assembly manual for the number of shims required for a given thickness. Substituting rubber isn't a good idea because it would prevent fore and aft movement.

Having said all that, this may not be your sloppy shifting problem.

[terribleted]

PVC pipe...lol no. Clark's sells a bronze bushing set for shift tube upgrade. I have used those and like them very much. Make sure that you are using a nice straight tube and rod in either case.

[PHX65CorsaHT]

Hey it has been awhile since I posted but I did want to reply to let you know how it went per your advice and others. I went ahead and made my own shims from plexi glass. Realigned the inner shift rod. But what I did that made the most incredible difference was line the outer shift rod tube with 3/4" copper pipe (instead of pvc). the 3/4" pipe fits like a glove sliding in, very snug put not so much that you'd have to pound it in. This was not my inspiration I know some others out there have done something similar. What I did was cut the copper pipe long approx 1/2 longer so it would be 1/4" long on each end. Then I took a ball peen hammer and put the ballinto the end and tapped it with another hammer to flair the ends. End result being the new inner sleeve can't move. It also tightened the diameter of the pipe just inside each end perfectly to function as a bearing for the inner shift rod. i put a light coat of lithium grease on almost the full length of the inner rod inserted it and mounted on the car. The shifting is so smooth and tight and positive it is an improvement way more than I could have anticipated or hoped. Highly recommend this modification to anyone. Cheaper and easier to do than the bushing set and you dont have to drill or otherwise molest the original equipment.

[Homebrew]

Had to ask did the copper tube go the entire length of the shift tube?

[PHX65CorsaHT]

Homebrew, Yep went the whole length with same treatment on other end. If you live in a colder climate you may want to just grease the ends of the inner rod and maybe a 4" section in the middle.