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37 Chrysler O.D. transmission rebuild.

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The tried & true saying about not being able to judge a book by its cover rings true with transmissions, especially when they are 85 years old. On the outside this trans looks pristine, but on the inside, the OD section was another story. If mice could eat cast iron, well.......it would still be a real mess. Fortunately, most of it has cleaned up fairly well & the only replacements needed are bearings & gaskets. However, it did require dismantling EVERYTHING, right down to the centrifugal weights in the annulus clutch unit. The problem is that I wasn't able to count the turns on the adjusting screws that control the weights. This is important since they determine what speed the OD kicks in. They also have to be matched. I haven't been able to find any specs on this adjustment & really don't want to have to remove the trans if I don't get ti right the first time. Has anybody come across any info on this. I have a hand scale, (for weighing fish), that I can use to get the adjustments even, but need to know how many pounds to set the screws to. I did come across a 24 page "Overhaul" manual that has great photos & details on how to rebuild this T-86, R-6, '37 Chrysler OD trans, but the weights were not removed. If anybody wants a copy of this manual, let me know.




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Hi jiminiy,

Here's the info I used to adjust the '37 Chrysler O/D I installed in my '34 DB convertible coupe. I just did this last week. This is from a Motors Manual. While the instructions says factory cut-in speed is 25-35 mph depending on make, I set my cut-in speed at 45 mph. I never found any initial starting point adjustment info either, so your idea of getting both pawl springs tension adjustment the same is a good starting point. Then drive the car to see what the cut-in speed is with your initial adjustment, and go from there. You'll have to remove the floorboard to access the top of the O/D adjustment plug, and as there wasn't enough access through the floorboard for me to rotate the drive line, I just left the wheels on the ground, put the car ind 3rd gear and rocked the car to get the transmission to rotate while watching the adjusting screws come around.  Also, I found that one "click" (half turn) was equal to 2 mph. Hope this helps!






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OUTSTANDING!!!!! Just the info I was looking for! I adjusted the screws in tight, as far as I was comfortable with, checked the tension with a pull type fish scale, (10lbs), & backed it off to 5lbs. I now feel at ease knowing I won't have to remove the trans to re-adjust, if needed. Everything else with this transmission has been pretty straight forward & brings back memories of when I overhauled a pristine OD, 40+ years ago for my 34 Plymouth.


Thank you so much "34 Dodger"!!!!!!!

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  • 1 month later...
On 7/11/2022 at 12:13 PM, 34dodger said:

Happy to help. Hope it goes well for you.

Here is follow-up on good advice from "34 dodger".  I finally got the overdrive in the car & couldn't be more pleased. Not only was the 5lb. setting on the fish scale helpful in getting a base adjustment on the clutch mechanism, but Bill's recommendation on "1/2 turn = 2mph", was spot on.  The only minor issue was with the new Coker WW tires that decided they were objecting to 60 MPH. This was expressed with the front tires who were getting "worked" more than the rear. 2 short 20 mile trips produced black streaks emanating from the bead & streaking across the fresh white walls. The 60 mile trip yesterday only produced one small streak, so I guess granny has broken in her new sneakers in spite of the sloppy steering "working" the front wheels. A steering box rebuild is the next project. Any recommendations?


BTW, 2 of the tires that came with the car had mfgr. dates of Aug 45. The other 2 were '65. The "45" tires are 3 months older than me, yeegaaads!



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