The Stovebolt Site Forums The Shop Area Driveline 58Slips out of 3rd

My 1958 Apache with a 283 slips out of 3rd while under acceleration. The transmission is a three speed out of 1967 camaro. It was rebuilt by a professional. I have attempted to set up per the assembly and shop manuals. I believe the setup is the cause of the problem, however I am not certain.

I have several questions. The assembly manual says the shift lever should be horizontal when in neutral, does horizontal mean level? When horizontal the tabs in the control box on the steering column are over to the passenger side. The assembly manual says the lever should be measured 8.5 inches from the center line of the steering wheel up the shift lever. Then 3.75 from the lever to the bottom of the steering wheel. My steering wheel is not smooth. It is a 58\59 variety. What am I missing here? How critical is the setup?

Here is some good information for older transmissions:

http://chev235guy.blogspot.com/search/label/Jumping%20out%20of%203rd%20gear

Do you have a 4 bolt side cover or a 7 bolt side cover?
A 67 Camaro transmission would likely be a full syncro Saganaw transmission (7 bolt side cover). It would not have the same side cover configuration as the original 4 bolt Muncie. The spacing of the shift rods would be different and they likely have to be bent to fit the current side cover. It sounds very likely that the lever(s) are not letting the gears fully engage.
Fred

I had the same problem yesterday. Had the 1950 1/2 ton fully loaded with various items to sell at the swap meet. Obviously, the rear was a bit lower than the front of the truck. Twice the gearshift lever jumped out of 3rd under acceleration, and once while cruising. I figured it was because of the angle of the transmission while under under a somewhat heavy load. If it happens again while the truck is empty I’ll know I have a problem to fix.

4 Bolt

The rods from the bottom of the steering column to the transmission are sloppy.

It is most likely a wear problem which can't be cured with an adjustment. There can be wear on the rod ends where they connect to the shift levers on the trans. The holes on the shift levers could be also be oversize. You can remove the rods, build up with weld and grind back to size. You could drill out the shift levers and install a bushing or weld them up and re-drill to size. There are bushings for the upper end where the rods connect to the shifter box. They are available from numerous aftermarket suppliers. Once you get the slop out you can make the adjustments.
Fred

If the shift lever has the transmission lug in its 3rd speed detent, then I'm sorry, your problem is in the transmission. Consider reading the link I posted above. Consider all info given in the thread, the truth lies within.

The transmission was rebuilt, so I want to try everything else first. The person who rebuilt it, came with solid and multiple references.

get in the truck put the selector in 3rd gear. Crawl under the truck, disconnect the shift rod from the 3rd speed arm at the trans and see if the arm is actually in the 3rd gear detent or if it moves a bit more. If it moves a bit more before hitting the detent, it may just be an adjustment. If it is all the way in the detent, it is probably something in your transmission.

Thanks everyone for the tips. I’ll crawl under the truck this weekend.

Did you get this ironed out?