Transmission pops out of third gear

[TJMack]

I looked back through old threads on this subject and found reference to shims between the bell housing and the engine block. I want to start with the simplest solutions first but I need a little guidance on this.

How thick are the shims supposed to be, and do I understand that they go on the two bolts that hold the throttle linkage to the engine?

The car (1931 Tudor) is new to me. The previous owner said he had a new clutch and balanced flywheel installed, so I'm suspect that the shims may have been left out.

[nkaminar]

The shims should be the same thickness as any gasket between the flywheel housing and the bell housing. No gasket, no shims.

I think you are grasping at straws and a transmission rebuilt is in the cards. Start with the shift tower to make sure the detents and plungers are all OK. Check to see if the fork that does the shifting is not worn excessively. Then look at the cogs that mate high gear together. If the cogs are worn then they can force high gear out of gear. The wear can act like little ramps that force movement under load.

[Charlie Stephens]

Originally Posted by nkaminar

The shims should be the same thickness as any gasket between the flywheel housing and the bell housing. No gasket, no shims.

I think you are grasping at straws and a transmission rebuilt is in the cards. Start with the shift tower to make sure the detents and plungers are all OK. Check to see if the fork that does the shifting is not worn excessively. Then look at the cogs that mate high gear together. If the cogs are worn then thay can force high gear out of gear. The wear can act like little ramps that force movement under load.

You forgot the part about "No gasket, oil leak".

Chagrin Stephens

[TJMack]

Thanks for the input, guys. I have to admit, I doubt the shim fix as well, but thought I'd ask. I can't see how a .006" shim can make that much of a difference in that location. And, wouldn't it cause an undue amount of stress on the housing when the other bolts are tightened?

Yes, it apparently did pop out on the previous owner but he forgot to mention that. He did say that the transmission was rebuilt, but who knows how good of a job was done.

I guess I'll start with the shift tower as suggested.

[J Franklin]

I remember they were .006. Did it pop out of gear for the last owner?

[Big hammer]

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X-2 on shift tower, a good round ball on the shifter, good rails and detents, the plungers live in a blind holes that hardened oils can gum up not allowing the plungers to freely move

[Clem Clement]

X# The end of the plunger should not be worn thru. Remove the trainy shifter plate and clean things out. My plunger hear was worn thru.
Clem

[Clem Clement]

X# The end of the plunger should not be worn thru. Remove the trainy shifter plate and clean things out. My plunger head was worn thru.
Clem

[Rob Doe]

TJ:

Do you have a copy of Les Andrews blue book, "Troubleshooting and Diagnostics"? Chapter 2 page 39 list 7 issues that will cause the transmission to pop out of high gear.

1. The input shaft nose is loose in the pilot bearing.
2. Incorrect drive angle of transmission to flywheel
3. Transmission mounting bolts loose.
4. Bent or worn shift fork/s.
5. Main front input shaft bearing worn or broken.
6. Warped flywheel housing.
7. Shift tower detent springs weak or broken.

[TJMack]

Thanks for that input, Rob. I've got some investigating to do.

[Terry, NJ]

When my coupe started to jump out of 3rd, i turned out to be a worn spline on the input shaft where it engages with the sliding gear. Solution, a new input shaft! Simple! A lot of work, but simple!
Terry