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Pictures of the Inside of a Bevel Gear Drive

Posted: February 13th, 2021, 10:08 pm
by Rustynut
Posting several pictures of a 1930 AA bevel gear drive rear end as I have it disassembled for inspection / repair.
Also a few pics of the pinion gear assembly.
Will hopefully supplement previous worm gear photos posted some time ago by "1crosscut"
Link to 1crosscut worm gear pics:
viewtopic.php?f=1&t=3844&p=20582&hilit= ... ive#p20582
Hoping these may help others in the future.

Re: Pictures of the Inside of a Bevel Gear Drive

Posted: February 13th, 2021, 10:09 pm
by Rustynut
Added pic of pinion gear assembly

Re: Pictures of the Inside of a Bevel Gear Drive

Posted: February 14th, 2021, 7:00 am
by BERLIN FORD AA
Thanks for taking the time to post this set of photos.

Re: Pictures of the Inside of a Bevel Gear Drive

Posted: March 21st, 2021, 6:34 am
by David R.
Thanks a bunch!! This is my next project. I have a spare 6.6 slow gear axle. My truck has a 5.14. The 6.6 is from lower mileage truck. I might end up swapping gear sets? What condition did you find yours in? I hear these axles were pretty bulletproof. Parts available?

Re: Pictures of the Inside of a Bevel Gear Drive

Posted: March 23rd, 2021, 12:40 am
by Rustynut
My truck has the 6.6, it was in reasonable shape when I pulled it apart, very little pitting and no chipped gears.
The pinion race though had a big chip out of it and was cracked from one side to the other, so re-affirmed you really need to pull everything apart and inspect/replace as necessary (everything felt tight and rotated smoothly, so considered not disassembling - glad now I took it apart and now know its in good shape). The race was a little hard to find but a fellow Model A club member had the part from a parts AA truck, you can typically find NOS or used parts in good condition. If its specific to the AA, it may not be reproduced as not much demand...
As for higher speed, I found a 5.14 ratio one but it turned out to have several issues (spider gears wouldn't seat properly, housing slightly distorted so the two halves wouldn't mesh together properly & fair amount of pitting on several gear teeth), so stayed with the original 6.6.
So I'm going with the 6.6 ratio rear end with a Mitchell overdrive instead, which should get me to ~ 45-50MPH when necessary (don't think I want to go any faster than that in a C-Cab anyway :D
Good luck with your project!

Re: Pictures of the Inside of a Bevel Gear Drive

Posted: March 23rd, 2021, 6:15 pm
by David R.
Will your Mitchell replace coupling shaft? Are prices for the Mitchell for a AA comparable to those for an A? I’m interested.

Re: Pictures of the Inside of a Bevel Gear Drive

Posted: March 23rd, 2021, 10:23 pm
by Rustynut
The Michell replaces the torque tube / main drive shaft, similar to the Model A car installation.
There are a number of articles and youtube videos that show the typical installation for cars.
The cost appears to be about the same as the car (same internal gearing, you can get either 26% or 36% overdrive) - I believe the main differences are in the length of the drive shaft and the shaft connection ends, and the speedometer gear ratio. Delivery is taking about 100 days for the truck as they build to order. Mine should be ready this week...
Check out their WEB site & give them a call, they have always been helpful in answering my questions.
https://mitchelloverdrives.com/

Re: Pictures of the Inside of a Bevel Gear Drive

Posted: March 25th, 2021, 7:14 pm
by David R.
I was hoping they made one that replaced coupling shaft like the Warford. I think I will see how it goes driving stock with high speed gears before I take the leap. I’ve been nearly a year trying to get engine done. I have some rusted rivets to replace in frame then I will start on rear end.