Speedo Driven Gear for 3.42 rear end.

[flip66]

Does anybody know what the stock drive gear is on the 200 4r transmission in an 88 RWD Cutlass. Everything I looked at on the web it appears to be the 13 tooth white gear I have added a GN rear end with 3.42 gears and need to change the driven or drive gear, all the web site calculations with the 13 tooth drive gear say I need a 34 tooth driven gear but the largest I can find for the Trans is a 30 tooth. If I change the drive to 10 tooth I can use a 27 tooth driven but I am guessing it would be a pain to change.

 

[megaladon6]

http://www.bowtieoverdrives.com/catalog/catalog.php?Action=GETSUBCAT&CATID=DA1
it's pretty easy to change both gears but make sure to LOOK at the governor springs and balls first so that if you slip and it falls apart you know how it goes back together.

 

[markiv427]

speedo gear ratio

i put 3.42 gears in my 1982 regal. i have GM Dealer Parts Catalogs.

For 3.42 gears and stock tires, you need a speedometer gear ratio of 2.714:1

I used an 8 tooth drive gear and a 22 tooth driven gear. 22 divided by 8 = 2.75 : 1

Pull the speedo cable end out of the transmission case, mark the end of one tooth with a marker, and rotate the output shaft and count the teeth.

Multiply the drive gear teeth by 2.714 to arrive at the needed driven gear. If there is no driven gear with enough teeth, you will need to change the drive gear or get a speed reducer for the speedo cable. GM made them.