Restoration is all about details, but I need some help reading the Assembly Manual for my '72 Cutlass Supreme Convertible. My car has the limited slip differential and gear ratio 3.42 that I find in the chart on page 4-093, giving code TM.
In the column Differential Carrier Assembly, under Tape Color Code, is mentioned Yellow and Green. Can anyone explain those colors to me please?

Furthermore, on page 4-094 a decal is presented, probably should be TM for my car? I still have to look to see if I can find a stamped identification on the rear axle as seen on that page.

Any help would be appreciated.

Thanks

 

This is a picture of the stamped code on my 1971 2.56 open axle (code R2). The stamping can be hard to see as there is usually some amount of rust and dirt on the axle tubes.

 

Is not the TM code, 3.42 ratio, for W30's only?

Has any one ever seen a K-code (McKinnon) manufactured rear axle? What models were they available on?

 

Thanks, Kenneth, Good to know where to look for the code and how it looks like. I don't know the code meaning of 1971, but probably the three last digits would be the day of the year the axle was built (the same as in 1972).

 

From the chart 4-092 it seems you're right: the 3.42 ratio was standard on the W30. Don't now how it ended up on my car, it was just this way when I bought it. I would like to check though what it really is - so I will take a closer look to find the axle code on my car.

 

That manual seems to be for a 1970 and older... the 1971 1972 seem to be in the CHEVY spot as this was the start of corperate housing now.
12 bolt olds is on the back side of the passenger tube and usually up side down... only 2 digit (number letter combo or 2 letter combo) suffix code
So you just might have the wrong info.