LM shifter question

[markplucenik]

I am hoping someone out there can shed some light on my problem. My car is a 66 Corvair, 6 bolt Saginaw 4 speed transmission. The car had a 3 speed in it when I got it and I just switched it to the 4 speed. The 3-speed worked fine but the shifter was sloppy so I rebuilt the shifter tube with Clark’s bronze bushing kit. That went fine, reamed the bushings for a proper fit. I inspected the used 4 speed trans before I installed it, removed the side cover, inspected all the gears, replaced the seals, and thoroughly flushed it. Everything looked good. It seemed to shift OK before the reinstall. With everything back together I cannot get 3rd or 4th gear. Reverse, 1st and 2 are fine but no 3rd or 4th . I’ve adjusted the linkage every way conceivable but can’t get the last 2 gears. I did have the side cover off and I admit it a pain to get the 2 shift forks back in correctly. It appears it would be impossible to mix up the 2 forks as they are completely different and if the #3 / 4 fork slipped out on assembly I would have to think it would cause a racket and do damage when I ran it but no noise or alerts. The shifter is the correct one , # 3872875 65-69 4 speed, with the correct dimensions. Any suggestions or ideas are greatly appreciated.

Thanks, Mark Plucenik

[66vairguy]

The 66 "Saginaw" has the shift detents in the side cover.

First --- Can you move the shift lever into 3rd and 4th? If so does the transmission stay in neutral?

If the shifter won't go forward to 3rd, or back to 4th, then it might be the shifter linkage.

If you can select 3rd and 4th, but the transmission stays in neutral, then that is usually a shifter fork that has drop out of place while installing the cover.

I've installed a few 66-69 transmission side covers and it is not easy. The local transmission expert taught me to use some grease to hold the shift forks in place while slipping on the cover. I found it is very difficult unless the the transmission is out of the car and ON IT'S SIDE since the shift fork will rotate out of place easily.

I always shift the control shaft by hand and turn the input shaft and check the output shaft to make sure all the gears engage. THEN I bolt the transmission onto the drivetrain and install the entire engine/trans/dif as a unit. Just me.

[markplucenik]

I did use the grease to set the forks. The only thing I can think is the 3rd /4th fork slipped and rotated out of the way. The shifter feels like I have the gears but I don’t. I just cannot help but think if the fork was not connected it would jamb up in the trans. I have driven the car up and down the driveway with "I hope" no ill effects. I did try today to remove the side cover from the transmission while its in the car. Because of the rear mount this is not possible /practical. The entire driveline comes back out tomorrow,

[erco]

Is it possible to remove the tranny while leaving the motor & diff in place? I plan to replace 4 syncros in a year or so.

[markplucenik]

I have been told it is possible but much more dangerous and greater chanced of breaking parts. Very little extra work to drop the entire thing.

[66vairguy]

I have been told it is possible but much more dangerous and greater chanced of breaking parts. Very little extra work to drop the entire thing.

Especially the 66-69 which had a longer transmission. It is a TIGHT fit. I drop the drivetrain with the support attached to the transmission. Much easier.

[Frank DuVal]

Yep, 45 years ago I changed a 4 speed on a 65 without dropping the drivetrain. Slid it back and almost made it clear, hmm, just a little interference and OK, it's off, now slide the replacement back in place, just put the output shaft into the diff and push to line it up, SNAP. Well, lets see how to change the output shaft with the transmission I took out. Learning experience. I never tried to remove just the transmission again. Now I know putting a jack on the differential and jack against the body might have helped, but may as well remove the whole drivetrain and fix what else is worn out/dirty.

[markplucenik]

I’ve removed the transaxle again. I do believe the 3rd 4th shift fork fell down and was not engaged with the cover. Friday I will try again to get it on with both forks engaged. I’m in Dover DE if anyone close wants to check it out. I have used grease to hold the forks in place before with “OK” results. Wondering about using a drop of the gel, super glue to hold them. I would think this would pop loose easy enough but hold long enough to get it together. Also, if I tried the super glue , put it on the round end of the forks (cover side} and slide the forks onto the shaft in 1 piece. Any thoughts? Again, a very small amount of glue.

Thanks again, Mark
Cell 302 943 1960

[66vairguy]

I’ve removed the transaxle again. I do believe the 3rd 4th shift fork fell down and was not engaged with the cover. Friday I will try again to get it on with both forks engaged. I’m in Dover DE if anyone close wants to check it out. I have used grease to hold the forks in place before with “OK” results. Wondering about using a drop of the gel, super glue to hold them. I would think this would pop loose easy enough but hold long enough to get it together. Also, if I tried the super glue , put it on the round end of the forks (cover side} and slide the forks onto the shaft in 1 piece. Any thoughts? Again, a very small amount of glue.

Thanks again, Mark
Cell 302 943 1960

Super Glue is typically a hard material when cured. I would not want that to end up between a sets of gear teeth!!! Just me.

Yes I've had the 66-69 cover on and off many times (and walked away for the day) before I got the shift arms in the cover levers. DO MAKE SURE the cover linlage is in the neutral position! To put your mind at rest --- you should work the shifter input shaft to makes sure ALL the gears engage (turn input shaft and observe output shafts turns vs. input) before installing the transmission.

[markplucenik]

Finly , got it together correctly. Thanks for all the suggestions. Mark

[66vairguy]

Finly , got it together correctly. Thanks for all the suggestions. Mark

Congratulations, glad you got it done. Amazing how the shift fork can avoid the other gears (usually) when it drops out of place .