I was lookin through the Tech Articles section and I found something odd.... the L03 T-5 Trans. has shorter gears than the TPI cars. why? Do the TPI cars have shorter rear gears or what? If they do, would it work to put them in the TPI cars?

Heres the page- Calculations

Thanx,
Chris

 

the M39 Transmission had the .63 ratio primarily because if it was not a TPI it was not classified as a Performance application and got better milage gears. Where the MK6 .73 5th gear was considered a closer ratio and a "performance" application.

Gm always needs to keep their fleet average MPG in mind when to meet EPA regulations. By putting M39's in non tpi cars it helps out the overall mpg of the fleet.

However, I am purposely put in a M39 in my car because I have a heck of a lot more HP than stock 305 , 3.42 rear gears and I should not notice a drop in "performance" in 5th. At least I hope . Plus I drive the Highway quite a bit and that should be a big + for milage.

 

Thats kewl. What about the shorter first gear? Is it better that the TPI cars have the taller first gear to keep the ratios closer, or is the shorter one in the M39 better?
Also, I just thought of this, how do the ratios of the first 4 gears compare to that of a Muncie 4-speed in a 68 Camaro?

 

Honestly I believe some of the info in that chart is incorrect. Every other sorce that I have come across comparing the MK6 and M39,they have the same gear ratio's 1-4 2.95. 1.94, 1.34,1

I have been researching parts and all of the WC V8 Tranies for f-body have speced out with the above ratios. Even parts wise they have the same cluster gear shaft....which would lead to the same 1-4 gears.