Rear-end gear ratio change
Thread Starter
Teching In
Joined: Oct 2002
Posts: 18
Likes: 0
From: Buffalo, NY
Rear-end gear ratio change I will be changing out my current rear-end with another one, but it has 3.42 gears in it. I know that my MPH will be off on the high side I believe, but will my odometer still register correctly? I wanted to know, because I have custom programming. If the odometer doesn't register properly, then can I have the gear ratio changes made at a dealer without it screwing up the rest of my custom program? I have the stock tire size on my car. Thanks.
I have 3.23 gears right now.
I have 3.23 gears right now.
TECH Apprentice
Joined: May 2002
Posts: 318
Likes: 0
From: Leg Dist #31, WA
Re: Rear-end gear ratio change If you do *not* reprogram for the new gears, then yes, the odometer as well as the speedometer will be off.
Numerically higher numbered gears (lower gear ratio) will spin the odometer faster. By 6% moving from 3.23:1 to 3.42:1. So, 50mph will read 53mph. And, for every 1000 miles you drive, the odometer will pile on 1059 miles...
Numerically higher numbered gears (lower gear ratio) will spin the odometer faster. By 6% moving from 3.23:1 to 3.42:1. So, 50mph will read 53mph. And, for every 1000 miles you drive, the odometer will pile on 1059 miles...
TECH Enthusiast
Joined: Aug 2002
Posts: 585
Likes: 0
From: CLARKSVILLE,TN
Re: Rear-end gear ratio change The speedo and odometer along with everything behind the transmission will be spinning faster to go the same mph as before. If you used a hypertech, you'll have to plug it in and push a button. If you had it programmed by Ed Wright, I think the going price is $150. But don't take it to a gm dealer or you'll lose your programming all together. They like to erase everything and start over.
Thread Starter
Teching In
Joined: Oct 2002
Posts: 18
Likes: 0
From: Buffalo, NY
Re: Rear-end gear ratio change Thanks for the replies. The dealer definitely just puts the PCM tuning back to stock, and it's for your particular car from what one of the technicians told me. This won't help me at all, because I will have non-stock gearing. I might have to take a drive to get the gearing changed, or blow 180.00 on the SLP module. This sucks.
Staging Lane
Joined: Nov 2001
Posts: 56
Likes: 0
From: San Carlos, CA
Re: Rear-end gear ratio change Go here for a cheaper solution:
www.camaroelectronics.com
The owner, Ira, is a registered user of this board.
www.camaroelectronics.com
The owner, Ira, is a registered user of this board.
