Overdrive overhaul

[Jim Yergin]

This weekend I finished reassembling my overdrive transmission. The thought of disassembling it, replacing the seals, gaskets and bearings would have been unthinkable to me before I found this forum. Thanks to blueskies’(Pete Anderson) and Normspeeds’ examples, I found the nerve to give it a try. My 1953 R10 overdrive transmission, which I bought years ago for my P12 wagon, turned out to be in pretty good condition and probably would have been all right if I had left it alone. However I would not have known that without taking it apart and the overhaul let me install the "fast" second gear.

The only suspect part I found was the low/reverse gear. Two of the teeth were corroded and pitted even though no corresponding teeth that meshed with them were in the same condition. The low/reverse gear in my original regular transmission was even worse. I ended up replacing the gear with an NOS one from Valley Vintage Auto Parts. I also installed the “fast” second gear and gear cluster that I purchased from Len Dawson, also NOS. Again, it was only because of what I learned on this forum that I knew to make that change. I purchased the overhaul kit from Portland Transmission Exchange as recommended by Normspeed. Tom at Portland Transmission Exchange was very helpful. Unfortunately Chrysler no longer supplies gasket sets for the overdrive transmission and neither does Tom’s aftermarket supplier. That meant I had to cut my own gaskets for both sides of the adaptor plate, which was no big deal. Also, I knew from Normspeed that the kit did not include the speedometer drive seal. I bought one of those from Len Dawson. What Normspeed did not mention was that the kit came with half a dozen baseball cards. Why, I do not know?

The instructions in the Chrysler overdrive transmission maintenance pamphlet (purchased years ago from Neil Riddle) as well as Pete’s and Normspeeds’ descriptions of their work were invaluable. I also followed James Douglas’ suggestion and tested the balking ring resistance and found it to be within specs. I will just add a couple of my own suggestions. When reassembling the overdrive, don’t forget to install the speedometer/governor drive gear or you will have to disassemble it to do so (guess how I know?). Also, the clutch gear sleeve can be installed two different ways. One way will not allow the overdrive unit to properly fit up with the main transmission case. Again, guess how I know this? Finally, I found that a ¾ inch hardwood dowel worked great when cut to the respective proper lengths to hold the roller bearings in place when installing the gear cluster and the reverse idler gear in the transmission.

Now I just have to paint the transmission, bolt it up to the engine and then reinstall them in the car. Oh yea, and then hope that it works.

Jim Yergin

[blueskies]

Oh yea, and then hope that it works.

Jim Yergin

Congratulations! I too had a great deal of fear around opening up my OD transmission. I had never seen the guts of a transmission before, and had no idea what to expect. I figured when I seperated the case, a million parts would fall out and scatter across the garage...

Hope your newly rebuild OD will last for miles and miles of smiles.

Pete

[Don Coatney]

Good job Jim! Anything is possible with a "failure is not an option" attitude.

[Joe Flanagan]

OK then, I guess I'm next.

[James_Douglas]

Jim,

That is nice. I look forward to hearing how it runs. BTW, when you tested the ring, what did it come in at ? Did you test it dry or wet or both?

Best, James

[Jim Yergin]

James,

I tested it dry. It came in at 2lbs.

Jim Yergin

[Don Coatney]

Jim,

That is nice. I look forward to hearing how it runs. BTW, when you tested the ring, what did it come in at ? Did you test it dry or wet or both?

Best, James

James;

What is the latest on your OD complications?

[Normspeed]

I'll say this, the OD definitely adds another level of complexity to it. After doing mine, I'd not hesitate at all to do a straight 3 speed. Piece of cake.

Jim, I'll pm you.

Oh yeah, and don't forget a gasket between trans and bellhousing. Seems that one doesn't come in most gasket sets but easy to make one.

[Jim Yergin]

Normspeed,

I replied to your PM.

I have that gasket, Tom did include a gasket kit for the regular 3 speed.

Thanks.

Jim Yergin

[Jim Yergin]

I was having trouble installing the shift rails and shift forks in my transmission. I consulted with Normspeed who referred me to Dodgeb4ya. Dodgeb4ya gave me directions that solved my problem so I thought I would post them here in case any one else needs them. Normspeed and Dodgeb4ya were terrific to go out of their way to help me and are prime examples of what makes this form so great.

Jim Yergin

There are the 2 shift rails. The one W/the wide 3 spaced grooves goes to the topside of the case. It shifts 1st and reverse slider gear. The lower shift raile W/ the 3 more closely spaced gooves slides in the lower shift rail hole in the case. It shifts 2nd and 3rd sleeve. Put the shifter forks onto the correct gear/sleeve(2nd-3rd) and 1st/reverse gear. then slide in either shift rail-3 grooves always to the front of case.Line up the deep screw lock hole in the shift rail W/ the hole in the matching shifter fork-screw in the lock screw bolt. Insert the other shift rail correctly into case and at the same time move the shifter fork you just assembled back and forth till you feel the other shift rail slide in all the way. The 1st assembled fork/shift rail assembly must be in neutral postion.There is a groove at the rear of both shifter rails that lets that little interlock pin move to the side to let both rails pass by each other. You didn`t need to remove that small 1/4" soft plug. I never have taken that out for OD rebuilds. Don`t forget to install the 3/4" shift rail plug at the front of the case. Good luck!

Bob