Posted by Ddd [172.68.35.50] on Monday, January 30, 2023 at 10:07:08 :
I need to go backwards!!!
Not the “direction” backwards. I mean regarding gear sets.
From a 4:89 to 5:83
I own a 1941 dodge 1/2 ton, WC12
If your reading this, and are a ww2 1/2 ton owner you know you got 4:89 gears, in the smaller 8-3/4” diameter R&P set, both front and rear. Most guys with later 3/4 ton trucks like installing the 4:89 R&P sets in their 3/4 ton trucks.
For faster road speeds
But I want to go SLOWER!!
Why?
Well first off the truck looses a lot of torque with larger 900-16 tires
Second, I live in a small mountain town above 8500 feet
All of my flathead dodges struggle with power loss due to altitude.
I never leave town with this truck, and it never sees highways.
So I’m contemplating swapping out the 4:89 gears for 5:83 gears as found in the 3/4 tons
So I’m not new to the swap, at least in the rear. I’m currently running a larger R&P diff (9-5/8” dia) in the rear, With the 4:89 gears.
And at this time, the front has the stock
4:89 gears in the original, 8-3/4” size diff.
The rear is an easy swap using three (3) gaskets to align the shafts to the diff.
And sliding in slightly shortened 3/4 ton rear axle shafts.
So putting in a large R&P with 5:83 gears is easy for the rear.
It’s the front.
I have a rebuilt early 8-3/4” diameter, 3/4 ton diff with 5:83 gears in it.
However, the side gears are machined for the 3/4 tons axle splines of 1-3/8” axle shaft splines.
(The 3/4 tons have 1-3/8” splines vs the 1-5/16” splines of the 1/2 tons shafts)
From what I gather, to make this work, I can do a few things:
1- tear apart the smaller diff and replace the side gears with those of 3/4 ton side gears
2- or cut and weld the front axle shafts to have matching splines of the 3/4 ton
Neither is something I’m comfortable doing.
So.. an inquiry.
A- has anyone here done the side gear swap on their own?
I mean, I’m not setup
To rebuild a diff. I assume one must tear the case fully apart to do this swap? Im simply not comfortable resetting the gear teeth after the side gear swap.
Or,
B- has anyone simply installed a SMALLER stock 3/4 ton diff into a 1/2 ton FRONT diff? Leaving the side gears alone?
I mean the difference in a 3/4 ton axle spline from a 1/2 ton is only 1/16” diameter.
Will there be long term damaging results sliding a 1/2 ton front axle shaft w/ 1-5/16” splines into a slightly larger 1-3/8” splined side gear?
I don’t off road this truck. Maybe engage 4x4 if the roads have snow. But again it rarely sees 4x4 mode
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