I swapped out the 2.73 gears in favor of the 3.42 (posi) in my 89' t/a, 5.0L TPI - automatic. I believe I have the correct gears (17 red and 44/ light green) But Im running into a problem with the "electronic" speed sensor. My old sensor has the 34-39 stamping on it and I need the 40 & up in a non-cable driven sensor to get the speedo in sync. Any one know of a fix for this? These sensors appear to be hard to find. Someone mentioned that I may need the one from a vette of the same era. Thanks a lot fellas

 

I believe the dakota digital sgi-5 is the easy solution.

 

+1

That's how I changed from 2.77 to 3.70 on my 86 TA. Works great.

Use shielded wire for the signal or you get speedo jumping while stopped at a light.

GD

 

Did you try to install the gears onto the sender you have? I was able to use my stock one when I went from 2:73-3:73. I believe my stock gears were red/red

 

You should see how noisy our ignitions are, exact same reason. Good advice.

 

Thanks fellas, it looks like the Dakota box is the only way to go. I was hoping there was an accommodating elect. speed sensor that I could pop in (along w/ the right gears) in the tail shaft for the 40-45 count. Sucks thats all I know.