LM shifter question

[markplucenik]

My car is a 66 that had a 3 speed transmission. I recently replaced the 3 speed with a correct 66 4 speed. That all went well, it seems to shift OK first through forth, but I cannot get reverse. I thought the actual shifter was the same, 3 speed and 4 speed but I was just told that they are different and the 3 speed shifter will not give me reverse with the 4 speed trans. Would a 4 speed shifter from an EM, 64 work temporally until I cand find the correct unit?
Pictures are of my 66 3 speed shifter.

[66vairguy]

First --- NO the 64 shifter is a different design vs. the 1965-69 (LM) cars.

Over the years there has been some confusion about "special" 3 speed shifters. Some EM cars had a 3 speed shifter that had a different throw and when used on the four speed, provided shorter shifts. The "shorter throw" LM 3 speed shifter is a MYTH. Many researched it and debunked the notion.

AFAIK --- All the LM shifter bases are basically the same. The differences were the brackets to attach the CORSA metal shift housing, or 500/Monza rubber shift housing cover. The pained vs. chrome shift lever is another contested topic. Some say ONLY the 3 speeds cars got painted levers, others say only the 500 cars (either 3 or 4 speed) got the painted painted shift lever. Bottom line --- all these LM shifter parts with different numbers seem to be interchangeable.

The "I can't get into reverse" is a common complaint due to worn out LM shifter tube parts". The coupler at the transmission can get loose or the pin hole in the coupler wears out. The transmission shifter rod is hardened and I've NEVER seen one with a worn pin hole, although some "characters" drill the hole larger for a bigger pin to put in the worn coupler instead of using a new coupler!!!

To rebuild the shifter housing (new guide pins), clean up the shifter tubes and install new bushings, replace the coupler takes some effort. Usually folks just install new nylon tube bushing and that improves things enough to get into reverse.

See shifter article viewtopic.php?t=18478

[caraholic4life]

The Three Speed Shifter your car came with SHOULD WORK the Four Speed transmission just fine. IF it doesn't, there is an issue with something else.

The Three Speed Shifter is actually something that many with Four Speed transmissions search for as it apparently has a little shorter throw which those that care about such things want for their Corvair. (This may or may not be accurate but I can't say one way or the other for sure)

Keep in mind that how the shifter is mounted at the base is important. It IS Intended to move a little forward and back to facilitate the movement of the engine and transaxle. It is NOT to be tightened down sung enough that it won't move. This is why there are different thickness shims available for the shifter base. (Clarks C537D)

Something you might look closely at would be the Shifter Coupler (Clarks C131R) at the back end of the shift rod where it connects to the rod coming out of the transmission.

IF the hole where the pin (Clarks C43) that goes through Coupler is worn/oval or oblong and has a good amount of "Play" at that connection, there is a good chance this is where your issue is. I have actually see the Pin wear a slot in it's self after years of use so look at the pin too.

Sometimes the Rubber part within the Coupler may have deteriorated to the point that the Coupler needs replaced but that isn't as likely as a sloppy connection at the pin.

Other places to look are at the shifter tube. There is an inner tube and an outer tube for late model cars that has a plastic bushing that may be broken/damaged, or even by now.....missing. Finding the OE Plastic bushings may be difficult but Clarks offers a Bronze Bushing Kit that may be of interest. (Clarks C1)

[66vairguy]

While I don't use the original style plastic bushing, the are available new from Clark's --- #C329.

The brass/bronze bushing requires some skill to make them fit optimally. Usually the inner tube is bent oblong (out of round) and may be rusty. Securing the brass/bronze bushing in the outer tube takes some skill or the retaining screws will bind the shifter inner tube.

For those with limited mechanical skill I recommend using the plastic bushings. Not the best fit, but much better than nothing (old bushings are often broken or missing). Also the plastic bushing does not need to be lubricated as the brass/bronze does.

If you have time and skills, then rebuilding the shifter and tube assembly is worthwhile. If you need to get the car working with limited work the plastic bushings are acceptable, If they need to be replaced.

[markplucenik]

Thanks for the quick reply's. I have already rebuilt the shift tube with the bronze bushings, I have adjustable reams so I got a real nice finish fit. They do take a little work for a proper fit. So it sounds like the 3 speed shifter will work I just need to fine tune the transmission end adjustments.?

Thanks, Mark

[66vairguy]

Thanks for the quick reply's. I have already rebuilt the shift tube with the bronze bushings, I have adjustable reams so I got a real nice finish fit. They do take a little work for a proper fit. So it sounds like the 3 speed shifter will work I just need to fine tune the transmission end adjustments.?

Thanks, Mark

Read the article I attached. Pins in the shifter housing can be an issue. The other problem is the missing "tang" on the inner shifter tube that the coupler shaft fits into to keep the coupler from turning in the tube. I've been told some break off the tab to rotate a worn coupler to make shifting into reverse easier. Unfortunately the clamp usually does not hold the shaft to keep it from rotating with the "tang" is broken off.

Years ago someone came up with a modification to use a Honda steering shaft coupler to replace the Corvair shifter tube to transmission coupler. It's on my "project" list to try one of these years.

[Frank DuVal]

With the three speed transmission the shifter rod did not need to rotate over to where the new 4 speed has reverse position, but now it does. Usually loosening the bolt holding the shift coupler to the shifter rod and twisting the shift coupler in relation to the shift tube fixes this. Better? If not, twist the other way. Do not change the "length" of this connection, just twist. Yes, the shift coupling is keyed to the shift rod, but there is quite a bit of slack in this notch/slot, so adjusting is possible.

[erco]

With the three speed transmission the shifter rod did not need to rotate over to where the new 4 speed has reverse position, but now it does. Usually loosening the bolt holding the shift coupler to the shifter rod and twisting the shift coupler in relation to the shift tube fixes this. Better? If not, twist the other way. Do not change the "length" of this connection, just twist. Yes, the shift coupling is keyed to the shift rod, but there is quite a bit of slack in this notch/slot, so adjusting is possible.

Good to know there's some slack there, I've never tried to adjust my coupler. Likely the only thing I haven't fiddled with since owning my car for 43 years. Recently I put a T-handle on my shifter which now extends further left into my knee zone. One day soon I may try to adjust it more to the right.