I am putting in a 3.42 rear end in my car. I currently have a 3.08. Do I need to replace both the plastic gear and the metal one on the output shaft of the trans? Or just the plastic one? Any help would be appreciated. Thanks.

 

I had a shop correct it for $37 when I switched gears,sorry no help.

 

Anyone else? Thanks.

 

Both gears are plastic. You'll probably be able to just change the driven gear.

 

Automatic or manual? what tire size? We need that info to tell you what speedo gears you need.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-

 

I changed from 2.73 to 3.42 in my car, and I had to change both the gears. It's not too hard to do yourself if you want to save a few bucks. I can't remember for sure what ratio size the cutoff is, but there's two different gears for the transmission output shaft. I had the red one for the 2.73 ratio, and had to switch to the gray one for 3.42. The speedometer gear article in the tech section of this site should have the gears listed that you need. I went to the Chevy dealer and they were able to look up the proper gears I needed on their computer. They had a chart on there with the proper combos. Oh yeah, I also had to get a different size sleeve for the cable gear as well. As long as you talk to a knowledgeable parts guy at the dealership, they should be able to hook you up with what you need.

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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."