Issues w/ '39 Synchro Tranny with Mitchell Overdrive

[SteveE]

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 tranny while I rebuild my '30 tranny. 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 tranny (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.

[Planojc]

Why not go with a cable shift from Mitchell. I have the cable shift in my 39 coupe and it works great.

[SteveE]

My car is a Model A with a 39 tranny in it. Different frame.

I don't understand why my kit didn't come configured for the 39 tranny 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.

[Bob C]

What is different about the frame?

[SteveE]

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.

[Chris Haynes]

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Lengthen the arm?

[SteveE]

Agree. Seems like the best option for the arm and rod, but not sure why the two shifters collide also.

[Bob C]

Does Mitchell know you have a 1939 trans?

[GeneBob]

From a similar post:

Originally Posted by GeneBob

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.

[Jordan]

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...

[nkaminar]

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.

[The Master Cylinder]

It appears that you have a Float-a-motor rear mount. Perhaps it is holding the rear of the transmission to high??

[Y-Blockhead]

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".

[SteveE]

Wow, nice car and clean work. Appreciate the picture for reference.

[SteveE]

Originally Posted by The Master Cylinder

It appears that you have a Float-a-motor rear mount. Perhaps it is holding the rear of the transmission to high??

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.

[Y-Blockhead]

Originally Posted by SteveE

Wow, nice car and clean work. Appreciate the picture for reference.

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.

[Y-Blockhead]

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.

[rotorwrench]

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.

[SteveE]

Originally Posted by rotorwrench

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.

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.

[SteveE]

Originally Posted by Y-Blockhead

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.

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.

[GeneBob]

Post #13 reminded me that I "recurved" the shifter for my 1935 trans to get the top forward a little ways. When I shifted with the original shift lever shape, the knob was way back almost on the seats (Tudor). I was very careful about how I went to bend it but found out it was pretty easy to just muscle it with the base of the stick in a vise.

[Colonial coupe]

I using a 36 transmission with a Mitchell and float a motor also. I did get the proper Mitchell shifter bracket from them for the V8 transmission, it is different and makes a difference. Like you I had to cut the V8 transmission mount on the left side to clear the battery. I had to get creative with some bends in the shift lever, but everything clears and works as intended. It does get a little crowded in there though.

[GeneBob]

Originally Posted by Colonial coupe

I using a 36 transmission with a Mitchell and float a motor also. I did get the proper Mitchell shifter bracket from them for the V8 transmission, it is different and makes a difference. Like you I had to cut the V8 transmission mount on the left side to clear the battery. I had to get creative with some bends in the shift lever, but everything clears and works as intended. It does get a little crowded in there though.

I wasn't smart enough to ask Mitchell if the had a different bracket for the later model trans. Wish I had.

[Bud]

I had the same problem. I had to cut off the ear on the bearing retainer just like you did. The aluminum shifter housing normally provide by Mitchell for the Model A Transmission does not work with a 39 transmission. I had a custom shifter housing made up for my 39 tranny. The bore has to be lowered which will clear the frame but also allow the floorboard to be installed. I tried to get Mitchell interested in making what I wanted, but they were not interested, probably too little demand. But they have been super to work with in all other respects. I think I have a sketch of the bracket, I will have to look for it if you want it. Just let me know.
My bracket still needs to be installed with a lot of washers underneath to get the exact position. Unfortunately I don't currently have pictures of the bracket and its mounting, but I will need to get some just for my reference. When I do I can share them.

[rotorwrench]

Just for information, there are several bearing retainers that were used in the early V8 cars that had the rear trans mount attached with the smaller round retainer with a big rubber donut. These are retrofittable to any of the top or side shift light duty Ford 3-speed transdmissions in cars up thru 1948 and and in 1/2-ton pickups up to 1951 or so. They can be found on flea-pay now and then. This way a person doesn't have to cut the rear mount. Here is a link to view what it looks like.
http://www.vanpeltsales.com/FH_web/F...ount_32-36.jpg

[Bud]

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Here is a sketch of the bracket I made for my 39 transmission:

[Bud]

This is a sketch of a bracket I had a shop make for me for my 1939 transmission:

[Bud]

Here is a larger view of my bracket sketch:

[Bud]

I do not have a photo of my bracket at this time.

[Bud]

Clarification: As I think about it, the sketch there is the standard aluminum bracket and I have notes regarding how much I had to drop the shifter shaft bore to clear the floorboard and to lower the shifter arm. Basically I had a piece of round stock welded to the mounting plate (all steel construction). Then the round stock was bored for the shifter shaft.

[SteveE]

Originally Posted by Chris Haynes

Lengthen the arm?

Yes, Mitchell has an extension that they sell already machined for the 1928 frame.

[SteveE]

Thanks! I had already cut them off. :-0

[California Travieso]

Correct me if I’m wrong, but I understand that you can put the 1939 gears in a 1932 gear case. Would that eliminate the problems with using the 1939 case and tower?

David Serrano

[Bud]

I have already done the conversion using the 1939 gears in a 1932 case. It is difficult on two points: getting the gears in the case can be done but requires installing the cluster gear shaft last and horsing the front thrust washer into position with dental picks--a couple hour job; also you need to make custom motor mounts because the B flywheel housing is narrower by 3/8" than the A flywheel housing. I know someone will chime in and recommend Float-A-Motor mounts (of which there is a B version), but those do not transfer the thrust of the rear axle thru the motor mount area as Ford originally designed. That thrust then has to find its way thru the Float-A-Motor mounts, the front engine mount, and engine pans, none of which are designed to handle it.

[Bud]

PS, that does not eliminate the "problems" with the 1939 case and tower. One will still need the proper shifter bracket.

[SteveE]

39 gears in a 32 don't change the clearance issue for the Mitchell shift lever arm. I installed the arm extender for the 1928 frame and I have the proper clearance now to hook up the battery box, brake line, and shift rod from the OD to the arm on the upper left of the transmission. Problem solved by Steve Mitchell.

[SteveE]

Note the OD arm is reversed when looking from the driver's door. I found that this gives me more clearance from the brake rod. Additionally, I reversed the Mitchell OD output arm from left-oriented to right by turning it with a wrench 180 deg and reattaching the selector shift rod nut and washer. I now have OD shift lever arm and selector rod clearance from the battery box and frame back to the OD arm. Still need to finalize and cut the floorboard.

[rotorwrench]

91A gears in an early model B or V8 gearbox require a custom made 2nd/high shift fork. The 91A shift fork is not designed to work with the early 18/48 shift tower that angles back. It will only directly fit the 68 and later shift towers.

[SteveE]

Not the subject of my post folks, but OK.