The Stovebolt Site Forums The Shop Area Engine Shop trans jumps out of gear

I have a 54 Chevy 1/2 ton with a 3 speed. Is it normal for it to jump out of first gear when the rpm increase? If I shift from 1st to 2nd quickly, it will not do it.
If this is not normal, is there anything for me to adjust? I tried adjusting the linkage but that didnt change anything.

If linkage adjustment did'nt help I would guess your rear motor mounts are worn out and the engine torque is popping it out of gear.

I had a '39 Chev Master Deluxe many years ago. It had some kind of vacuum-assisted tranny that would pop out of high gear. I never got to fixing that and stored it for 26 years until I bought my '48. I know I'm no help here but your question brought back some fond memories.

Mine was popping out of third. I removed the trans cover and found the shifting fork was worn. After replaceing that and cleaning up the springs and ball it is working fine.
Steve

Thanks for the response.
In the shop manual, under troubles and remedies,
it mentions replacing the DETENT SPRING. I am not sure what that spring is. Is that the same springs you are talking about?

Yes I did not replace them. I just cleaned the socket the ball sets in and all the other parts on the cover. Then I replaced the shifter fork.
Steve

There are dimples in the cover and the detent springs push the balls into the dimple to keep the arm in place. The balls , springs, etc. are all contained in the cover and held in place with 2 nuts. Here's a pic.

http://chevy.tocmp.com/1949_53shop/07trans/7_005.HTM

Curt B.

Thats it. I replaced the shifter fork and seals for the shafts and cleaned everything up real well. If you need the seal part number let me know
I have it at home.
Steve

Steve, I could use that part number for the transmission shift shaft seals. And also a source for them. We are going after fluid leaks in trans and engine and can't find those seals anywhere. Thanx Tim

parker,

Good luck with your endeavour, but keep in mind that the detents are there only to hold the forks in position when everything is up to snuff.

If you have a problem, like a worn input shaft, bad motor mount or some other faulty component that is "forcing" the transmission out of a particular gear, then all the detents in the world aren't going to hold things where they belong.

Popping out of gear is not at all uncommon on these rigs. The only adjustment that usually works is an adjustment to the checking account... made out to AAMCO.

Stuart

Tim/51,
The seal number is 340849 its a National Seal # but I am sure that most suppliers use that or can cross to their number. My local parts house did not stock them but of course could order. I found a set at a local bearing and seal supplier. They were also less money then the parts house.

Good luck. If you need me to I can get more and send them to you.
Steve

Another problem that apparently can create this symptom is a worn input shaft bearing (might not be the exact name for the bearing) in the transmission. I've seen it mentioned a number of times over the years in articles and forums, it typically happens when there is a lot of torque on the input shaft of a standard transmission, the only cure is to replace the bearing. Years ago I had a 1983 toyota 4x4 that would literally jump out of first gear while accelerating, I had just enough money to replace all the bearings (5th gear bearing was also going bad) and that cured the problem.

Don't know if that's happening to you, but just wanted to raise the possibility.

Thanx Steve I'll go witha that # and see what comes up locally here in Seattle. Appreciate the quick response. Tim