Transmission speedometer gear question
Thread Starter
Intermediate
Joined: Feb 2006
Posts: 32
Likes: 1
From: Ajax Ontario
Transmission speedometer gear question
I just got my transmission back from overhaul and I need to put in a speedometer gear. I looked through the AIM but I can't find which one to put in. Anyone enlighten me please? It's an M21, 3:36 rear end and P235 70R15 tires.
Thanks
Thanks
Drifting
Joined: Jul 2002
Posts: 1,943
Likes: 1
From: Rosemount MN
I'm thinkin' a 20 tooth will get you close.
I'm just installing a 3.36 in mine, just regeared the speedo from the stock 20 to a 22 for the 3.70 that I just hand grenaded. Stock ratio was 3.36 and had a 20 tooth, but M-21's could have a 7-8 tooth drive gear so without taking the tailshaft housing off and counting the drive gear teeth, you may need to try a couple of different driven gears.
I'm just installing a 3.36 in mine, just regeared the speedo from the stock 20 to a 22 for the 3.70 that I just hand grenaded. Stock ratio was 3.36 and had a 20 tooth, but M-21's could have a 7-8 tooth drive gear so without taking the tailshaft housing off and counting the drive gear teeth, you may need to try a couple of different driven gears.
Racer
Joined: Mar 2005
Posts: 487
Likes: 0
From: Jacksonville FL
this site has a calculator that should help you.
http://www.tciauto.com/Products/Tech...eedo_gears.asp
good luck and i hope this helps,
Mike.
http://www.tciauto.com/Products/Tech...eedo_gears.asp
good luck and i hope this helps,
Mike.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
Racer
Joined: Aug 2006
Posts: 363
Likes: 3
From: Norwalk Ca
Speedometer Accuracy
Can anyone help me out with my speedo accuracy? I have a 72 and know that my speedo is not accurate. It shows me doing 100 mph at about 3200 rpm. The only thing is I'm barely passing traffic that I estimate at 70-75 mph. Does anyone know of a good speedo shop in southern California that could help me dial in my speedo?
Thanks all.
Thanks all.
