Is a T56 with casting number: 13-86-066-904 the one with the .50 overdrive? That's the one with the better mileage right? It's out of a '93, and I thought that years T56 had the .76 6th gear ratio?

 

If it's out of a 93, it will not be the MN6 with .50 overdrive ratio. There were two different 6-speeds offered in 93 (depened on what rear gear ratio you got). The T-56 for 2.73 rear ends was garbage IMO - don't mess with it! 1st to 2nd gear is way too wide. The other tranny came with the 3.23 rear end cars (look for G92 on trim tag)... it's a good tranny. Both 6-speeds in 93 had a .62 final OD.

 

Well I want the T56 with the .50 6th. So I should stick with the '94-'97 T56 then huh?

 

was it the M28 or the M29 that came with the 3.23 in 93?

 

M29 came with the 3.23 rear end.

 

Rock on

I just bought a M29 to replace the factory M6 from my car which had 180k miles on it ...i think it would have lived longer if i didnt run it out of fluid

Mods and drag radials probebly didnt help it much either

 

Are those RPO codes for the car or tranny? I didn't think the tranny had anything to do with the rear gears??

 

The rear axle gears only determined which 6-speed you got in '93... all 6-speed cars in 94 or later had the 3.42. In 93, you could get the standard (2.73) or performance axle (3.23) with a 6 speed. With the standard axle, you would get the M28 (junk) - it had like a ~3.36 1st gear, but the same second gear as the M29! Performance axle (GU4?) got a M29, which had a much closer 1st gear.

 

1.i thought the 93 t56's only came rated at 400 tq,the 94-97 came at 450 but seems to be way underrated.

2.what do you do for the speedogear when putting the 93 in a 94.