2.56 to 3.42 calibrating speedo.

[jc-pa]

I plan on changing the rear ratio in my 95 caprice wagon with a 4L60E transmission. I'm concerned about changing the speedo, I see lots of what look to me like hokey buffers you put into the vss ckt but I would like to do it with the cars own software or hardware. The problem is I don't know where to get credible info on this subject. Thats why I'm here. Is this a straight forward modification,(relatively easy) Or something other?
Thanks
Jerry

[TommySS]

If you're car has OBD III diagnostics (I think it does), then the dealer can do it with a Tech 2. The older caprices use a gear-driven speedo so a gear change is needed there.

[jc-pa]

obdIII? It has an obd1 connector but the eeprom is part of the ecm and can't be removed, it needs to be flashed.
I'm concerned the dealer will have problems with a 3.42 because the car wasn't built with 3.42s only 2.56 and 2.9?. The 4L60E uses a tone ring on the output shaft of the trans. instead of a gear driven vehicle speed sensor.

[TommySS]

The dealer can flash it to compensate for the 3.42

[jc-pa]

Thanks TommySS

[TommySS]

Let us know how it comes out, m-kay?