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Advice needed - Transmission stuck in 4th
Posted by: kingofthebunnies ()
Date: September 07, 2022 12:13PM

Hi everyone. I was cruising along this weekend. Car had been running just fine with no issues. As I approached a red light I went to shift out of 4th but the car transmission was stuck in 4th. I needed to call a tow truck to get the car home, as I would have had to drive through 30 minutes of stop and go traffic with nothing but 4th gear.

Engine starts and runs fine. I can let the clutch out to get rear tires to roll, but otherwise shifter is stuck in 4th.

I got the car up on the lift at home and everything seems fine underneath with the shifter linkage, shift shaft, and shifter connection to trans. I took the inspection cover off of the trans and the 3-4 shift fork will slide fore and aft a bit, but not enough to get the thing out of gear. Everything looked nice and tidy inside the trans. No obviously messed up gears. Fluid drained out nice and clean.

Car: 1966 Monza convertible with 95hp engine and 4 speed trans.

Any advice that saves me from having to drop the powertrain out of the car is much appreciated!!

Attachments:

Re: Advice needed - Transmission stuck in 4th
Posted by: v8vair ()
Date: September 07, 2022 12:40PM

I would say one of the 3 little dogs in the syncro assembly had broken or come loose, unfortunately complete disassembly required.

1964 Bill Thomas Monza Replica Racer
1964 Spyder Street Car
1998 Honda Prelude Dirt track car
1967 Crown V8 under construction
Mike Levine
Cumming Georgia
North of Atlanta

Re: Advice needed - Transmission stuck in 4th
Posted by: joelsplace ()
Date: September 07, 2022 01:46PM

It sure looks dry inside.

Joel
Northlake, TX
5 Ultravans, 138 Corvairs and counting...

Re: Advice needed - Transmission stuck in 4th
Posted by: RexJohnson ()
Date: September 07, 2022 02:23PM

That looks to be a '64-'5 trans. The shift fork looks like it is overextended to the front as the syncro dogs that Mike is talking about look like they are traying to pop out. If you could get all 3 of the dogs compressed back in place you may be able to slide the syncro sleeve back into place. A piece of wire or a hose clamp might work. If one of the dogs fall out, you're back to taking it apart. The 3rd gear brass ring might need to be realigned as there is a notch for the dogs to go into.

RJ tools
Salem,Oregon

Re: Advice needed - Transmission stuck in 4th
Posted by: kingofthebunnies ()
Date: September 07, 2022 05:54PM

Appreciate the advice fellas! You are correct RJ that this is the trans from a 64-65 car that was swapped in at some point in its history.

Ill try to see if I can get it back into place where it is, otherwise I’ll be prepping to drop the powertrain ????.

Re: Advice needed - Transmission stuck in 4th
Posted by: v8vair ()
Date: September 07, 2022 06:10PM

If you have a lift or real high jack stands you can get the trans out without removing the engine and diff , look in the 66 manual

1964 Bill Thomas Monza Replica Racer
1964 Spyder Street Car
1998 Honda Prelude Dirt track car
1967 Crown V8 under construction
Mike Levine
Cumming Georgia
North of Atlanta

Re: Advice needed - Transmission stuck in 4th
Posted by: Cheepfk ()
Date: September 08, 2022 08:50AM

Pretty sure that date code on your 4-speed says it's a 1963.

"C 7 3" = March 7, 1963

Re: Advice needed - Transmission stuck in 4th
Posted by: caroseiii ()
Date: September 09, 2022 09:22PM

I agree; a 63 transmission. Try large screwdriver or pry bar to slide the synchronizer back. I hope you don’t have to take it out. Might be s good time to source a more correct transmission.

C.A. Rose
Metairie, LA
1962 Spyders

Re: Advice needed - Transmission stuck in 4th
Posted by: vairmech ()
Date: September 10, 2022 04:53AM

caroseiii Wrote:
-------------------------------------------------------
> I agree; a 63 transmission. Try large screwdriver or pry bar to slide the synchronizer back. I hope you don’t have to take it out. Might be s good time to source a more correct transmission.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

A more correct trans like a 66-9 would require a different differential and input shaft.

If this turns out to be a real 63 trans then it is a 12 spline input shaft and the 64-5 trans is a 14 spline input, so not a quick swap there either.

I had this very situation happen on a rebuilt 65 trans that I did. I was able to pop the dogs back in but when I did a quick shift they popped right back out and was jammed in 4th. I exchanged the trans and had no issues with the other one.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

Re: Advice needed - Transmission stuck in 4th
Posted by: caroseiii ()
Date: September 10, 2022 06:35AM

Touché, Ken. Maybe a chance to source a correct 66-69 transaxle.

C.A. Rose
Metairie, LA
1962 Spyders

Re: Advice needed - Transmission stuck in 4th
Posted by: v8vair ()
Date: September 10, 2022 07:13AM

I’ve got a good used 65 trans that was never picked up , cheap plus shipping if wanted

1964 Bill Thomas Monza Replica Racer
1964 Spyder Street Car
1998 Honda Prelude Dirt track car
1967 Crown V8 under construction
Mike Levine
Cumming Georgia
North of Atlanta

Re: Advice needed - Transmission stuck in 4th
Posted by: kingofthebunnies ()
Date: September 19, 2022 07:50AM

We’ll gentlemen, I was able to pop the “dogs” back in and the thing is shifting perfectly fine again. For what it’s worth, the 1965 chassis shop manual calls these “synchronizer hub keys”…
I went for a long enthusiastic test drive and everything seems to be working normally.
There was no indications as to what the “root cause” of this failure was, and I’m certainly concerned that it’s going to get all jammed up again, and at a less convenient time or place.
This is is a relatively freshly rebuilt transmission, sourced from the Corvair Ranch 3 years ago… probably has all of 500 miles on the thing. The trans that came out of the car at the time was also an early trans as it had the stamped side cover with filler plug. I’m not sure when that was installed, as I’ve only had the car about 6 years now. Is it possible that I caused some problem when installing it…?
Or perhaps maybe there is something weird going on with the mix of transmission/differential in my particular car causing a problem?
Any thoughts as to potential things to look for in the current setup to drive long term reliability improvements here?

Re: Advice needed - Transmission stuck in 4th
Posted by: Wagon Master ()
Date: September 19, 2022 10:35AM

2 items.
1. You still need to insure complete engagement but several shift shaft and outer shift tube adjustments can be made to slightly limit shifter travel into 4th and 2nd.
2. Why does the mainshaft and shift forks appear completely dry without a hint of a film of lube?


Friends Don't Let Friends Drive Stock
Been Aircooled Since 1973
Northwest Ohio 45840

Re: Advice needed - Transmission stuck in 4th
Posted by: caroseiii ()
Date: September 23, 2022 08:19PM

It’s lowered its carbon footprint, perhaps.

C.A. Rose
Metairie, LA
1962 Spyders

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