i put in a 4th gen rear end with 3.42's. the guy at the GM parts counter said i cant just put in new gears for the speedo. i thought that was all i had to do. he said the speedo worked off of a sensor and that i need to go to some tranny shop he suggested and they will put an adaptor on and calibrate it. is this right? or can i really just buy the new gears.

 

I hope you told him what he could kiss.

3.42's are a stock ratio for 3rd gens. You can just order the right parts and install them and they will work perfectly.

If I was more familliar with the VSS system I'd give you the information to buy what you need but you'll have to wait for some one with the right part #'s, sorry.

 

what parts do i need. just the gears right?

 

do i only need to go in and ask for gears

 

I think the guy just misunderstood what you wanted. Either that or he was a tool and thought you didn't know what you were talking about.

Yes, all you need is the right gear. I can't tell you which one though. There's a formula to tell you which one but I don't know it off the top of my head.

 

If you have an electronic speedo, those parts are kinda pricey. The 40-45 sensor is 107.30, the gears are cheap though. It will depend on how tall your tires are, on what gears you'll need. I had a standard firebird with cable driven speedo, p215r65-15 and it had 38/15 gears. I had that 342 in my GTA while I was rebuilding my other rearend and had a 39/15 gear combo in it. With 245/50/16s and the speedo was pretty close.

 

go here to figure out what gears


http://www.700r4.com/SpeedOCalc/



go here to find out the part numbers, scroll down to the tranny section



https://www.thirdgen.org/newdesign/faq/thirdgen.shtml