trotter73

I was wondering what the rear end gear ratio for an early 76 was, it's an L48 if that makes a difference.

Pipman

I am pretty sure it is 3.08. I just bought my 76 about two weeks ago and have been gathering info since.

jn76vette

It's hard to say without the code on the housing, could be 3.08 (OA), 3.36 (LR), 3.55 (OB), or 3.70 (OC)

The Dude

With the L-48 you have a better than average chance of finding 3.08s in there. But, like somebody said, it's hard to tell without the code off the differential.

You can get in the ballpark by yourself. Jack up the rear of the car and support it. Put a chalk mark in the driveshaft and a little piece of tape or something on the wheel. Put the car in neutral. Rotate the rear wheel by hand while you watch both the chalk mark on the driveshaft and the tape on the wheel. Count the number of turns the wheel makes in the time it takes the driveshaft to rotate once.

Just a tad more than 3 rotations = 3.08.
Almost exactly 3 and a half rotations = 3.55.
Just a little less than 4 rotations = 3.70 or 3.73.

You get the idea.

diablo kid

I have a book that says with M20 manual transmission the standard ratio was 3.36 LR code and auto transmission 3.08 OA code.

Red_Shift

I think most were made with 3.08.

Mike Mercury

shouldn't that be the other-way-around:

Count the number of turns the driveshaft makes in the time it takes the tire to rotate once.

The Dude

Crap. You are correct. My bad. Duh.

Sleper

I find it easier to rotate the tire 10 times and count the number of revolutions. 308 almost 31, 336 is 33 1/2, 370 is 37 Good luck

EricBing

is there another way to find out? Like for instance 3000 rpm at 70 mph ? I too have an L48 automatic

73 Scott

Mine has 3.36 and it runs an 3000 rpm at 70 mph.
If it's a 4 speed it's likely 3.36

jb78L-82

As always go here for every spec you want on your particular C3:

https://www.gmheritagecenter.com/doc...t-Corvette.pdf

ALL 76 L-48 automatics had a 3.08 gear. The 4 speed L-48's came standard with 3.36 gears but could be ordered with the optional "highway" gear of 3.08.

ykf7b0

My 76 with auto has the factory 3.08's.

AdamMeh

As a reference - our '77 (same gear offerings as the '76 model) came with a L48 4spd and 3.36 gears.