gears and tune question

[turbotko]

Quick question. I've got a complete 3.42 torsen diff sitting on the floor in the shop (minus the axle tubes) and am getting ready to swap it into my 2.73 geared TA.

I wanna swap the gears this weekend but am worried about what the auto tranny will do after the swap without a tune. I can deal with the speedo being off and will get it tuned as soon as the longtubes are on, but is the tranny gonna shift right?

Also, anybody think I can use the pinion shim outta the 3.42 diff when I swap into my 2.73 housing? Or should I use the original pinion shim outta the 2.73 diff.?

[ninobrn99]

arent they different carriers? I would imagine your shifts would be off also.

[mysticZ]

Your spedo will be off but as far as the tranny, don't worry. My ECU is programmed for 4.10 but I stepped back to a 3.23 gear.

[koolaid_kid]

Your computer will be confused and not know when to shift. You will need to reprogram it for a 3.23 gear, then it will shift correctly. I went thrugh the same thing when I went from a 2.73 to a 3.42.

[turbotko]

I put the gears in last weekend and have been driving it for the last couple of days. The tranny shifts fine although the convertor locks up at odd times. Just got my PCMforless tune in the mail today though so it'sallgood!!