The Stovebolt Site Forums The Shop Area Driveline 3800 rear axle

My '55 3800 has a full floating dually rear axle. I know the gear ratio is 5.14:1. Are there any higher ratios available, like 3.73s or something? Is this the same axle used in the 3/4 tons?

It is the same axle as the 3/4 tons, with only a few differences depending on year. The only gear options are the 4.56 and the now hard to find 4.10. Both are 3/4 ton ratios for the most part (4.56 was an option on 1 tons in some years), and the 4.10 was only used from '68-'72.

Can I get these ratios new? If so, where? All I'm finding are ring and pinion sets for the 1/2 tons.

It's not likely you'll be able to find any new gears. The best you can hope for is a salvage yard, craigslist, or maybe someone on this site has one.

Another option is swapping to a newer axle. I saw in another post you were thinking of swapping a K20 drivetrain it. If you have a Full Float 14 bolt, you could swap it in and use your original hubs. Of, course, you'll have to address the brakes though.

Chris

Ok, thanks for the info. A set of 4.10s would be awesome because that is what is in the axles of the K20.

I actually have a 4.11 geared 14 bolt out of an 83 SRW truck in my garage right now. My original plans were to use hubs from a 14 bolt Dually to narrow things up a bit. I ran into some issues when it came to figuring out the brakes.

I would have use a Drum off a later model Van and use a spacer on the backing plates. Or, I could go disc brakes.

I robbed calipers and rotors from an 03 van for my project so I could parking brake. Well, the rotor only fits the early hub from the backside, Which moves everything inboard ALOT.

On a whim, I put the Hubs from my 54 on the 14 bolt. As it turns out, The WMS on the axle is only going to be 64.5" vs 63" for the dually hubs. An added bonus is the rotors slide right over the early hubs.

I haven't been to the maching shop to have an axle flange made, but everything looks reall promising.

You can get the complete bracket assembly from a Chevy dealer. If I remember correctly, it was under $100 per side. The van brackets cost slightly more than the trucks though.

parts breakdown

Dually hub and rotor

If you will go to the "Tons of Fun forum, There is a LENGTHY article titled "Anyone change out their 5.17:1 diff gears?" concerning 4:10/4:11 gear sets from 1967 thru 1972 which are a DIRECT bolt in for our 1947 thru 1953 3800 ONE TON TRUCKS. If you have any questions, that forum is the place to ask concerning 3800 trucks. Jerry