im going to be swapping my stock 2.73 rear for a 3.42 rear out of a 1991 Z28. Ive got a 700R4, what do i need to make my speedometer read correctly... speedo gear? which one?

 

16T Blue (8640518) Drive, 44T Dk. Gray (25513051) Driven

 

anything else i need to swap out? or just those two parts?

 

will those same speedo gears work in a 4l60e trans?

 

Depending on what gear you have now, you might need a new housing.

The same gears will work in a 4L60E with the same gearing and same size tires.

 

Sorry to interrupt, but Apeiron, how did you figure that out? From online gear calculators or...? I'm doing the exact same thing (switching from 2.73 to 3.42 gears) and from researching past posts everyone stated that you need a 15T gray drive and a 41T yellow driven gear. Just curious.

 

Ben, do you think the speedo gears will work in a 4l60e also?

 

I used a gear calculator I wrote a few years ago. It gives the closest combinations possible without reading high. It also spit out a combination with a 15T drive that may have used the 41T driven, I don't remember. In any case, 16 / 44 = 0.3636 and 15 / 41 = 0.3659... the difference between the two ratios is pretty small.

 

OK, I understand now. I realized that the 2 different combinations weren't that much different, but I just wanted to make sure I wasn't missing anything. Thanks.

 

im just changing the rear out, same tires, same 700R4... those two gears is all i need, correct?

 

You might need a new VSS housing to match the size of the new driven gear.

 

how much? and can i get one from gmpartsdirect.com what part number?

 

From what I understand (through searching), you will not need a new VSS housing. I also asked this question a week or 2 ago just to make sure, check it out:

https://www.thirdgen.org/techbb2/sho...hreadid=280805

 

Actually, now that I look, it appears that the 25513051 I gave is actually the P/N for the gear and sleeve unit together.

 

sweet, thanks guys