Mark Williams is stepping up! More diff options.

rtj

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Nov 5, 2011
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Just got this in an email:

The C2 and C3 Corvette differentials come from the factory with a 17-spline inner flange yoke that can be prone to failure. Our solution is to upgrade the rear by modifying a stock Corvette posi-traction carrier with 30-spline side gears and adding a one-piece 300M 30-spline inner flange yoke shaft that eliminates the bolt-on flange yoke.
300M forging, double heat treated and shot peened
Increased strength with 30-tooth involute profile spline
Removable billet u-joint caps with studs and ARP® nuts
Uses standard GM c-clip to retain yoke shafts
100% machined and produced in house, in the USA
Part Number 50245 - C2/C3 Corvette Axles, Inner Yoke Shaft (stock differential)


https://www.markwilliams.com/50245....il&utm_term=0_1a187180f2-de42a852c8-426849805

To upgrade the stock Corvette rear to use our 30-spline Inner Yoke Shafts, the posi-traction is modified by slightly increasing the bore size and using a 30-spline axle gear that is common to the 12-bolt GM passenger car posi-traction units. A simple machining operation to the posi-traction case is required. Instructions are provided for the modifications, but new, modified Eaton™ posi-traction units, with the 30-spline side gears, are available to save you time and assure the job is done right.

Part Number 19670-MOD

https://www.markwilliams.com/19670-mod.html


Comments?
 
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That's certainly promising. There really hasn't been much support since Tom's Differentials started slowly closing their doors. The side yokes are pricey, but the material spec and the fact that they are 30 spline is much better than what is currently available with 17 spline stockers. I'd also like to know what kind of spiders are available as that could be an issue. Nice to see them breathing life back into the C2/C3 rather than just writing it off and swapping in something entirely different. While that is an attractive option, it is often outside of the skill level of most enthusiasts.
 
Looks like nice stuff. Would be good to know how much "improvement" these parts provide.
 
These are the oem dimensioned forged yokes from Echlers at $389 each.

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These are the new MW pieces.


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Pretty meaty. I think MW sells the spider gears too.

I had been thinking of buying another kit from Tom's, but this might be the ticket.

I got a couple of trans yokes from MW and the quality in nice. My guess is they offer outer axles soon.
 
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Is that would work with a tuned slip diff ? Hope that the clips side end is way harder than factory !
Van steel's selling Tom's bits now.
 
Is that would work with a tuned slip diff ? Hope that the clips side end is way harder than factory !
Van steel's selling Tom's bits now.

I think they are c-clips like a 12 bolt Chevy. Yeah Van Steel, I saw that.

Welcome back! Did you ever install those high rate springs?
 
I have a complete Tom's set-up that I bought a few years ago, just as described by Mark Williams - never installed it. If someone needs it, I will dig it out and see what all is there. I know it has the axle shafts, side gears, clutches, and shafts. I am now using a Detroit Speed Hammerhead differential which also uses GM 12-bolt stuff.

Pappy
 
Yes, I did . Run 1000 lbs spring in front and Guldstrand race spring at the rear, cannot say the rate of the rear accurately, just under the Daytona rate I think. The car is much faster on the chronometer. Spent lot of money with a so called suspension guru last year for not much results except the front springs. But I had a good time racing it, I just need to drive better :sweat: But going quicker brings other problems, mainly front brakes !! How well....
 
Yes, I did . Run 1000 lbs spring in front and Guldstrand race spring at the rear, cannot say the rate of the rear accurately, just under the Daytona rate I think. The car is much faster on the chronometer. Spent lot of money with a so called suspension guru last year for not much results except the front springs. But I had a good time racing it, I just need to drive better :sweat: But going quicker brings other problems, mainly front brakes !! How well....

What was the company that sold you the springs?
 
Well, I'm picking up projects for when I retire again. I already had a nice posi case stripped and painted, so I checked with Tom's. Got a 4:11 kit and HD case cover. I'm really not too keen on the 3:73 gear I have now.
 
When they sold me the second kit they told me I'd need to do some machining. Basically, Tom was no longer there and I got the feeling they were just selling off what was left.

The FAST guys probably buy the MW stuff as to compete there you need $$$$.
 
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