Issues w/ '39 Synchro ****** with Mitchell Overdrive

S

SteveE

Member
Any ideas besides fabricating new parts or cutting my frame to make this Mitchell OD work without interference? Thinking a rod with a U-shaped channel to clear the frame and battery box or a longer shifter pivot arm linking the rod to the OD.

Running a '39 synchro top loader ****** while I rebuild my '30 ******. The aftermarket Model A frame (I think aftermarket) appears to not match the Mitchell design. I cut off the left "rabbit ear" on the '39 ****** (two ears on the output near the U joint used for trucks in the day).

Issues:
- Mitchell OD shift lever interference with '39 shift lever and Mitchell OD shift pivot arm and
- OD shifter rod and arm cannot clear the frame or the battery box.
 

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Why not go with a cable shift from Mitchell. I have the cable shift in my 39 coupe and it works great.
 
My car is a Model A with a 39 ****** in it. Different frame.

I don't understand why my kit didn't come configured for the 39 ****** and the frame. All it came with was a modified shift tower bracket for the shift arm that interferes with 2nd and 3rd gears. No cable was provided, but the cable would hit the frame too. What a cluster.
 
Good question. Looks aftermarket to me.
The Mitchell linkage was designed to pass through the areas it is hitting on my frame. Tells me that the frame is likely not original to the vehicle as it's been restored 2x since 1930. Regardless, they should have given me a modified cable pull system as I am never cutting into my frame just for a Mitchell OD.
 
From a similar post:
GeneBob said:
Although I have a Ryan overdrive, I have the Mitchell shifter and brackets. I am running a 1935 transmission which had the same interference issues. I modified the u-joint clamshell in a similar way to clear the parking brake rods. The Ryan mounts at the rear of the driveshaft tube. I had to adjust the shifting rod to the longest length I could in order to clear the shifter crank on the driver's side. I also had to cluge a hold down for the bracket since the bolt pattern on the bracket is made for the Model A transmission top. As far as shifter stick interference, I shortened the OD shifter and rotated it back until the two cleared each other. My OD shifter is pretty far back when not in OD.
Because the trans is not the Model A trans, I didn't mind making these modifications in order to fit it all together. You might also try bending the OD shifter rod to put an angle at the end near the shifter crank in order to clear the frame.
It was a tight fit to adjust, bend and grind everything to fit on the side of the trans.
Added: I also had to sand/grind some clearance into the underside of the floorboard for the bracket because it would thump under acceleration.
Click to expand...
 
It would be a different bracket for the 39 transmission I believe. That would probably solve the majority of your problem. They didn't make reproduction frames...
 
My Mitchell overdrive works perfect with my Model A box. Call or email Mitchell company to get a quote for the cable. Or modify as GeneBob posted in #9. I think the cable is the best solution.
 
One of the problems I see is the bend in your shifter places it WAY farther back than a Model A shifter, causing the interference. Mine shifter doesn't come back far enough to tangle with the Mitchell shifter and I extended the Mitchell shifter 4".

51160676125_71b0e90c23_z.jpg
 
The Master Cylinder said:
It appears that you have a Float-a-motor rear mount. Perhaps it is holding the rear of the transmission to high??
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Good catch. It is installed after the Mitchell and rests lightly on the top of the frame. Had to fabricate that float-a-motor top bracket too as it is not meant for the 39 U joint.
 
SteveE said:
Wow, nice car and clean work. Appreciate the picture for reference.
Click to expand...

Steve, Have you tried installing the arm on the shifter, then connecting the rod? Tthe arm should be pointing straight down when the Mitchell is in neutral. I just crawled under my car. I is real tight in there but should fit.

Someplace I have a picture of the cable setup. I will try to find it.
 
Well, here. is one picture of the cable setup. Not the one I was looking for tho. the cable connects to the Mitchell, doing away with shifter and linkage. I will keep looking.

51004067328_e16fbc52c0_z.jpg
 
The later V8 transmissions are longer and wider than the Model A gearbox so don't expect original model A stuff to work with a different transmission. Folks have made them fit the model A configuration by adding pedal support and clutch linkages but adding in a Mitchell OD complicates things.
 
rotorwrench said:
The later V8 transmissions are longer and wider than the Model A gearbox so don't expect original model A stuff to work with a different transmission. Folks have made them fit the model A configuration by adding pedal support and clutch linkages but adding in a Mitchell OD complicates things.
Click to expand...

Thanks. I am aware of the adapters needed from Klings and installed those fir and shifters need to be bent according to Steve Mitchell on the phone. It's my frame that is in the way. Adding a small extender arm and will "blow torch" :-) the shifter to move the 39 shifter forward.
 
Y-Blockhead said:
Well, here. is one picture of the cable setup. Not the one I was looking for tho. the cable connects to the Mitchell, doing away with shifter and linkage. I will keep looking.

51004067328_e16fbc52c0_z.jpg
Click to expand...

Thanks for the help. I was told to add an extender arm and heat the shifter and bend it forward out of the way of the OD shifter. Or, shorten the OD shifter. Will play with them to see.
 
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