I need to kno the part# for the correct speedo gear for a 3.45 9bolt A/T
I have the speedo gear for a 3.23 rear end but the reading is way to far off for my liking. Any info appreciated thanks


Ryan.

 

Which driven gear you need depends on which drive gear you use, your tire size, and how accurate you want it. For closest accuracy, here's the best setups. note: tire diameter is unloaded, as in not on car.
26.1" diameter (and shorter), like 235/60-15, use 15:40
26.7", like 275/40-18 or BFG 295/50-15, use 15:39
15 tooth drive gear, gray, part number 8642620
driven gear depends on '82-'88, cable-only, or '89-'92, hybrid.
these driven gears come with their proper-offset (plastic) carrier, and don't fit the older aluminum carriers, so you can set aside the old aluminum ones.
40 tooth is black. cable is part number 1362048, hybrid is 25513047
39 tooth is brown. 1359273 25513046

 

So i have 225-60-15 about 25.8" tall so i guess i need the 15:40 but do i need to just buy the one gear or do i need to buy the 40 and 15 tooth gears?

 

You'll need to buy both, but that's way cheaper than a speeding ticket and what the ticket does to your insurance.

 

Before you call your local GM stealership, look at www.gmpartsdirect.com They usually have the best price in the U.S.