I have a 1995 3.4 auto with 3.23

i am putting in a 1999 3.42 posi

i also have 17 in rims instead of 16

HOW do i program my tranny and PCM to recognize and compensate so my speedo and shift points are not WAY off

 

The shift points will not matter, and your speedo wont be off too bad. Switching from 3.08s to 3.42s results in an 11 percent difference (at an indicated 100mph, you are actually going almost 90). With the 3.23s factory there wouldn't be enough change to warrant adjusting it in my opinion.

 

Running around without proper PCM input informarion can and will screw with the auto in that car. I'm not going to flame the above post, nor post a rolleyes, I'll just leave it at that.

Send an email to the guys at www.pcmforless.com, they will fully educate you on the matter.