Mitchell Overdrive Installation

[Hoogah]

Just wondering about you guys that have a Mitchell. Did you do the installation yourself? Was it tricky? What equipment (and how much skill ) do you need? How long did it take you? Would you do the same again? What tips would you pass on to someone contemplating this? (I have late-'28/29 running gear.)

[JohnLaVoy]

The Mitchell is a great choice, we have one in the sedan. The area that is most critical is the installation of the shaft into the rear end. You need to be comfortable with making that change. I think Tom Endy has posted here regarding working on the rear end and what it would take. I've done it a couple of times but he has done it many more times and probably forgot more than I know. It does require the rear end coming apart so you will need a spring spreader for one thing.

[LopezCarguy]

Just finished installation and can say it was not easy, the hard part is taking the differential apart and installing the pinion...major adjustments need to be made when putting it all back together...still think it is a good idea, just be prepared for these hurdles...also need a inch pound torque wrench to set pre load on pinion and some kind of adaptor for wrench to pinion. 12 to 15 inch pounds setting

[afuncar]

the rear end does not have to come apart only the torque tube and drive shaft need to come apart,to remove pinion gear from drive shaft. the diablo a club has excellent dvd for this installation. I have helped with two installations and didn't feel they are out of the average persons abilities but I do recommend the video before you start.

[Tom Endy]

The rear axle assembly does not have to be taken apart to install a Mitchell overdrive. It has to only be removed from the car. To do the job safely a spring spreader is required. The spring should be left safely attached under the car.

Once the rear axle assembly is out of the car, remove only the torque tube. The oil in the banjo does not have to be drained. You will need some type of drive shaft puller. to pull the drive shaft and pinion assembly from the banjo. The Mitchell folks can sell or rent you one.

The drive shaft with the complete pinion gear and bearing assembly is pulled from the banjo along with the drive shaft. If you do not unbolt the two large pinion nuts the pre-load on the bearings will remain intact (if there actually is one).

The drive shaft is then removed from the pinion assembly. You will need a gear puller for the job. Do not hammer on the end of the threads of the drive shaft, use a proper puller.

Once the drive shaft has been removed it is replaced with the Mitchell stub shaft and spline coupler. The pinion assembly is then reinserted back into the banjo. The Mitchell overdrive can then be attached and all is reinstalled in the car.

Obtain a copy of the March\April 2012 Restorer, there is an articles with photos detailing the task.

With four willing workers at a technical seminal the task can be accomplished from start to finish is about 5 to 6 hours.

Tom Endy

[MAG]

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Like Tom says "5 or 6 hours" with 3 or 4 people who are used to handling wrenches is about what it takes us to do it. We have installed several ( about a dozen) and have always followed the instructions that Mitchell provides with each unit. The instructions do not call for dis-assembling and adjusting the Pinion Bearing assembly. However, we do check to see if the pre-load is within spec. So far we have not had to re-adjust any of them.

[Tom Endy]

Originally Posted by MAG

Like Tom says "5 or 6 hours" with 3 or 4 people who are used to handling wrenches is about what it takes us to do it. We have installed several ( about a dozen) and have always followed the instructions that Mitchell provides with each unit. The instructions do not call for dis-assembling and adjusting the Pinion Bearing assembly. However, we do check to see if the pre-load is within spec. So far we have not had to re-adjust any of them.

A number of years ago we held a seminar to install a Mitchell overdrive in a beautifully restored 1930 Town Sedan. The owner who was in his 50's had owned the car since high school where he had driven it every day. In his late 40's he restored the car.

When we started the seminar I asked him how many years ago had he overhauled\restored the rear axle assembly. He said he never had it apart, only out of the car where he wire wheeled and sanded and painted it so it looked beautiful.

When we got the pinion assembly off the drive shaft we found it had no pre-load, and in fact had thrust clearance. I took the nuts loose and inspected the pinion bearings and double race. They were shot worse than any I had ever seen, yet the car had been running just fine.

Prudence dictated that we replace both pinion bearings and the double race. I had all in stock. We assembled everything onto the Mitchell stub shaft, torqued the 15\16" nut on the end and clamped the shaft into a vice. I was then able to set the pre-load by feel by turning the double race by hand.

There was nothing we could do about the carrier bearings and races that were probably in the same condition as the pinion. We put everything back together and road tested it with the Mitchell and the car ran as good as it looked. A testimony to the ruggedness of the Model A Ford.

Tom Endy

[kressej]

A friend and I picked up a Mitchell at the factory late last fall and put it in my Vicky over the winter. Also replaced the clutch, clutch plate, balanced the flywheel and put in a sealed bearing U-joint from a Lincoln (see Drake). No special tools really, had the pinion pressed off and rented the Mitchell tool to reinstall the pinion. We are rank amateurs, and it went real well and I am glad to have it. Driving to Puyallup from La Grande, OR in July and it should come in real handy. Go for it!!!

[msmaron]

just drove back from French Lick and have one and did 60 mph most of the way and it was great..Would not ever be with out it!!
it was easy to install....takes about 8 hours the first time

[tbirdtbird]

a quick note if you run a Mitchell most would agree to run the standard 3.78 gearset, assuming you have a stock motor

[Hoogah]

Tom Endy said:
Obtain a copy of the March\April 2012 Restorer, there is an articles with photos detailing the task.

I'm not familiar with this publication (Newbie!!). Where would I get a copy?

I'm learning a lot from these replies. Thank you!!

[Dodge]

High compression head and a Mitchell together it will be the best thing you could ever do.

[tbirdtbird]

and add a Stipe .330 lift cam and let that engine breathe a sigh of relief