Model AA 4 speed trans

[hemiphil]

Hello,
Finaly the snow is gone and can drive the old AA. I have packed abouth 50 miles on it and found a few bugg's. I have rebuilt the steering box, fixed a seat spring issue and installed a new light harness. Minor stuff. Now the transmission is popping out of 4th gear. What would cause this issue. If i keep a pressur on it runs good, but as soon as i let go, it pops out! Also there is a vibration when i lay of the gas at 25mph. I think it may be a u-joint. Do they still reproduce U-joints.

Thanks,

 

[Joe K]

Jumping out of 4th COULD be worn gears - not impossible to remedy as I see replacement NOS gears are available from the parts houses.

BUT it may be way simpler - just a worn out input shaft pilot bearing (the one in the center of the flywheel.

YOu may end up removing the old transmission input shaft, rebushing the bearing nub, and replacing the bearing. Not that big a job and can be done without spending the hundreds on new mating gears.

Oh! I see a new transmission input shaft IS available - at $585. Hope for the lesser option issue.

The vibration you're seeing above 25 COULD be the flywheel/input shaft bearing issue (if present) or could be a bad U-joint.

The UJ on this truck SHOULD be the newer "yoke" type pattern - which the standard rebuild kit should take care of. http://www.macsautoparts.com/ford_model_a/model-a-ford-universal-joint-rebuild-kit-9-pieces.html

If not, new UJs are available from your local auto parts houses that deals with Dana-Spicer (who were and are still the manufacturer of the later 4 speed truck UJs.)

There may be a wait for a new UJ - Dana-Spicer makes Ujoints in "runs" and you have to catch the latest run.

 

[Fullraceflathead]

I have a AA 4 speed in my '28 roadster pickup.
Mine does not jump out of 4th gear but I do notice that the shifter moves some when it goes from being under load to coasting. Does your shifter move some when going from a load to coasting?

 

[hemiphil]

Thanks for the info.
Is the u-joint the same size as a passenger car?
Also the shifter moves when under a load.

 

[Bob C]

The AA u-joint is not the same as the A. You may not have
a u-joint at the transmission unless you have the service replacement
coupling shaft.

Bob

 

[hemiphil]

The AA u-joint is not the same as the A. You may not have
a u-joint at the transmission unless you have the service replacement
coupling shaft.

Bob

So the rebuilt kit from Mac will not do, where else can i look? Here is the set up i have on the truck. It sure looks like the drawings you posted. Is the pilot bearing the same size as the A? thanks,

 

[Joe K]

The rebuild kit from Macs (or others) WILL do as the only thing that changes between the AA UJ and the Car UJ is the spline of the yoke section.

If you have an original AA UJ, it can be rebuilt provided the yokes are not destroyed.

Joe K

 

[hemiphil]

The rebuild kit from Macs (or others) WILL do as the only thing that changes between the AA UJ and the Car UJ is the spline of the yoke section.

If you have an original AA UJ, it can be rebuilt provided the yokes are not destroyed.

Joe K

Ok now i get it! LOL
Thays good information.
Thanks

 

[Bob C]

The setup you have is like the left picture I posted, there is
no u-joint at the transmission. The car u-joint kit is not the
same as the truck. The car is A-7084 the AA is AA-7084 and
the cross is about 1/8" narrower than the car one.

Bob

 

[hemiphil]

Hello,
with this set up i still have to remove the rear end or the motor to re move the u-joint? Or can i just remove the short shaft?