30/31 Ring Gear Question

AA Ford Discussion Group relating to the repair and restoration of your AA Ford.
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Rustynut
Posts: 11
Joined: October 31st, 2020, 11:06 pm
Body Type: C-Cab
Model Year: 1930
Location: Campbell, CA

30/31 Ring Gear Question

Post by Rustynut » January 10th, 2021, 4:26 pm

Hi all,
In the process of restoring an early '30 C-Cab ice truck (bevel gear rear-end)
I was planning on converting the original 6.6:1 ratio rear end to the high-speed 5.14:1 ring/pinion.
Located & purchased a 5.14 ring and pinion assembly, but upon close inspection, the ring gear housing does not fully mate together, due apparently to some deformation to the collar on the gear housing (see photos below).
High Speed Ring Gear1.jpg
High Speed Ring Gear1.jpg (440.78 KiB) Viewed 581 times
Ring Gear Housing Closeup1.jpg
Ring Gear Housing Closeup1.jpg (417.49 KiB) Viewed 581 times
Ring Gear Housing Gap1.jpg
Ring Gear Housing Gap1.jpg (277.97 KiB) Viewed 581 times
Questions to anyone with experience in this area (appreciate all input):
1. How critical is the mating of the housing - can the offending section on the collar simply be filed down, or might this cause the spider gears to be out of alignment if the housing is not mated exactly as originally machined? Note also the mating surface is quite rough.
2. An alternative may be to swap the high-speed ring gear with the original 6.6 ratio ring gear to use the original housing assembly, which is in good shape. However this would require drilling out the rivets on both and either re-riveting or bolting in the high speed ring gear. I'm not set up to be able handle the required riveting, and assume the rivet holes won't match any standard bolt diameter? Anyone have any experience with swapping ring gears?

David R.
Posts: 178
Joined: August 17th, 2019, 1:52 pm
Body Type: Chassis
Model Year: 1930
Location: WV

Re: 30/31 Ring Gear Question

Post by David R. » January 10th, 2021, 5:58 pm

Not yet but I’m following. I have a 5.14 in my truck but found a lower mileage 6.6 axle I’m thinking about using but obviously want the higher ratio.

Rustynut
Posts: 11
Joined: October 31st, 2020, 11:06 pm
Body Type: C-Cab
Model Year: 1930
Location: Campbell, CA

Re: 30/31 Ring Gear Question

Post by Rustynut » January 10th, 2021, 7:51 pm

Hi David,
Depending on how authentic you want to keep your truck, another option could be a Mitchell overdrive (built new for A's & AA's).
I have one on order, was hoping to have both higher speed rear end & the overdrive, getting to a top speed of 50+ when necessary.
A fellow C-Cab owner has the 6.6 with the Mitchell and is happy with it, but would still like to upgrade with the 5.14...
Or if you can find an original Warford...

KimVanOrder
Posts: 709
Joined: August 11th, 2013, 4:25 pm
Body Type: 82-A Platform
Model Year: 1928
Location: Hamilton, Mich.

Re: 30/31 Ring Gear Question

Post by KimVanOrder » January 11th, 2021, 11:17 am

If it was mine, I'd file / grind it to fit. I think the spider gears are so slopy that there should be no issues.
KVO
Dec. '28 AA

KimVanOrder
Posts: 709
Joined: August 11th, 2013, 4:25 pm
Body Type: 82-A Platform
Model Year: 1928
Location: Hamilton, Mich.

Re: 30/31 Ring Gear Question

Post by KimVanOrder » January 11th, 2021, 11:18 am

If it was mine, I'd file / grind it to fit. I think the spider gears are so slopy that there should be no issues.
KVO
Dec. '28 AA

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