Differential ratio

[kip Foss]

Can anyone tell me if there is an easy way to determin the diff. ratio on a 450 slc? Can it be gotten off the VIN? In my earlier hot rod days we used to just jack up one wheel, turn that wheel around once and count the times that the driveshaft went around. If the car had Posi-traction you had to get both wheels off the ground. Is Posi-traction very common on US spec. 450slc's?

[4NDELIT]

I have a 450SL, and I know that I have a limited slip (posi traction), so I think it musta come on a few of them. I'm not sure about the differential ratio though, I think it's under 3.

Kip -

From the road tests I've read, the SL and SLC of a given year had the same rear end ratio.

Starting in 1972, that was 3.07:1; it was still 3.07:1 in 1976. By 1980, it was reported to be 2.65:1 (I don't know what year the changeover occurred). 380SL/SLCs and 560SLs were 2.47:1.

The turning/counting method you describe should work and the result should be one of the ratios above (your drive shaft should turn either a bit over 3 times, a bit over 2.5 times, or a bit under 2.5 times).

BTW, I've read that some european SLs had 3.27:1 gears!

[TSL]

I have a 72 SLC and it has a 3.36 ratio. You can find your ratio on the right hand side of veh. forward, on the diff. case number. Might be very hard to see, I had to clean the heck out of it.

[TSL]

Hey Kip,
Didn't know it was you, until I ck post. Been swamped with business since first of year. Not one day off. Still have a package I am sending to you, have not forgotten.
Best,
Tim