Technical Cad Lasalle transmission problem

The CLS box (side shift) behind my flathead falls out of high on the overun.
How can that be prevented?
Any and all suggestions gratefully received.

 

How much wear is on the 2-3 shift fork?

 

If the shift forks and detents are in good condition, mis-alignment of the input shaft will cause this problem. I don't know what kind of setup you have but the input shaft has to be dead center with the crankshaft. Most older workshop manuals have a section detailing how to check this. It could also be loose bolts either on the bell housing or the transmission.

 

If none of that helps, look for wear on the sides of the shift splines on the input shaft, and the mating synchro splines.

 

"falls out of high on the overun."
This is British for pops outta 3rd??
Bloody Hell!

 

No, it's British for "pops outta 3rd when I let off"

 

I would think excessive play on the main shaft or main shaft bearings allowing the shaft to move, fork and gear stay in place, but now the wrong place when the shaft can walk around

 

Had a friend in high school (60 years ago) with a car with the same problem. Drive shaft was a little too long. Shortened it. Fixed it.

Check it out.

.bjb

 

Thanks for your interest and suggestions.
My set-up uses an Offie 3640 trans adapter which accommodates the long input shaft and allows use of standard Ford throw-out bearing and clutch fork. When it was first assembled I did check input shaft length and had to cut about 1/8" off the nose to prevent bottoming in the flywheel. Your suggestions have given me much to check when the engine is next out and I'm thinking that maybe the input bearing is walking forward a little. Also it has been suggested here that wear on the ends of the dog teeth may be the cause.

 

As another poster noted, you should use a magnetic base mic to indicate on the center of the transmission adapter (where the input shaft collar comes through) to see if it is centered in reference to the crank. You may need to create the concept of "off set bushings" to move the transmission adapter to center the shaft of the transmission with the center of the crankshaft flange. I've had to do this with late-model scatter-shields on SBC's - is a pretty common issue - especially with aftermarket transmission adapters and/or scatter shields.

 

sounds like the transmission needs to be disassembled and inspected
it could be worn gears, case or thrust washers or something else entirely.
close examination of all parts and assembly should reveal the problem.
a year appropriate Cadillac or '50 Oldsmobile shop manual will give you correct assembly.
it may be as simple as an issue with the thrust washers on the cluster shaft, worn or wrong arrangement allowing the gears to not fully engage..
just a wild guess..

 

As a side note the first transmission I ran behind the flathead in my Deuce roadster was a Cad Lasalle three speed.
Used the same Offy adapter as the one your using. Did you add any type of seal between the adapter the counter shaft pin hole? Reason I ask I experienced gear oil leakage between the pin hole location and the adapter. It was due to the lack of experience on my part fifty years ago. Solved the problem by making a suitable sealing arrangement.
Ronnieroadster

 

Thanks for that. I will check out.

 

Thank you. Yes I did instal a seal.

 

Thanks for that. Yes, it needs to be torn down for inspection.
I have a shop manual and have stripped and rebuilt a number of these transmissions (and always replace that awkward clip on second gear with a modern C-clip).