Speedomter off
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Joined: Feb 2006
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From: In The Hills S.C.
Speedomter off
After installing 2004R trans in 74 (replaced 400) and going back to stock size tires I find that my speedo is 6 mph fast. What info do I need to get correct speedo gear. If I pull driven gear and count teeth do I need to replace gear with more or less number of teeth? 3.08 rear/2004R trans/225-70-15 tires. Thanks guys!
Drifting
Joined: Jan 2004
Posts: 1,991
Likes: 3
From: Piscataway NJ
There are four drive gears for the 2004r
Green 10 tooth 8639906
Orange 11 N/A fom GM
Red 12 8634935
White 13 8634934 This Part number has changed
There are 6 driven gears
Brown 26 - 25502669
Black 27 - 410731 I believe this on is N/A
Yellow 28 - 416765
Green 29 - 403999
Blue 30 - 561035
White 31 - 403417
Look at what you had in the 400 and do some calculations. The 308 with a 13 drive and 29 will be over.
13 drive 30 will be under. You can check with TCI but the price of the gears are close to GOLD. GM is cheaper.The speedo may have to be recalibrated if you want it right on.
Green 10 tooth 8639906
Orange 11 N/A fom GM
Red 12 8634935
White 13 8634934 This Part number has changed
There are 6 driven gears
Brown 26 - 25502669
Black 27 - 410731 I believe this on is N/A
Yellow 28 - 416765
Green 29 - 403999
Blue 30 - 561035
White 31 - 403417
Look at what you had in the 400 and do some calculations. The 308 with a 13 drive and 29 will be over.
13 drive 30 will be under. You can check with TCI but the price of the gears are close to GOLD. GM is cheaper.The speedo may have to be recalibrated if you want it right on.
Last edited by Artsvette73; Oct 25, 2007 at 11:46 AM.
Burning Brakes
Joined: Nov 2006
Posts: 954
Likes: 40
2022 C3 of the Year Finalist - Modified
Try this link:
http://www.transmissioncenter.net/sp...n_______va.htm
I bought from him an adaptor to increase the speedometer reads after I change the rear end ratio.
Avner
http://www.transmissioncenter.net/sp...n_______va.htm
I bought from him an adaptor to increase the speedometer reads after I change the rear end ratio.
Avner
Melting Slicks
Joined: Jun 2002
Posts: 3,284
Likes: 0
From: I just killed your thread Redneck AZ
Try this link:
http://www.transmissioncenter.net/sp...n_______va.htm
I bought from him an adaptor to increase the speedometer reads after I change the rear end ratio.
Avner
http://www.transmissioncenter.net/sp...n_______va.htm
I bought from him an adaptor to increase the speedometer reads after I change the rear end ratio.
Avner
Safety Car
Joined: Aug 2001
Posts: 3,685
Likes: 202
From: Waterford Mi
Melting Slicks
Joined: Jun 2002
Posts: 3,284
Likes: 0
From: I just killed your thread Redneck AZ
Try this link:
http://www.2004r.com/speedoCalc/speedocalc.shtml
http://www.2004r.com/speedoCalc/speedocalc.shtml
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
If you add one tooth to your driven gear you will be fine! The GM tolerance on the speedometer is +/- 3-5 mph. You are at 6 and this should bring you in to the tolerance level.
The rule on this is one tooth equals 5 mph. +/-. If the speedo is off the same amount across the board, there is nothing else you need to do! The speedo can be re-calibrated, but this is much harder to do than just sticking a new gear in the car.
The rule on this is one tooth equals 5 mph. +/-. If the speedo is off the same amount across the board, there is nothing else you need to do! The speedo can be re-calibrated, but this is much harder to do than just sticking a new gear in the car.
Last edited by Willcox Corvette; Oct 25, 2007 at 08:34 PM.
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Thread Starter
Advanced
Joined: Feb 2006
Posts: 78
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From: In The Hills S.C.
speedometer off
If you add one tooth to your driven gear you will be fine! The GM tolerance on the speedometer is +/- 3-5 mph. You are at 6 and this should bring you in to the tolerance level.
The rule on this is one tooth equals 5 mph. +/-. If the speedo is off the same amount across the board, there is nothing else you need to do! The speedo can be re-calibrated, but this is much harder to do than just sticking a new gear in the car.
The rule on this is one tooth equals 5 mph. +/-. If the speedo is off the same amount across the board, there is nothing else you need to do! The speedo can be re-calibrated, but this is much harder to do than just sticking a new gear in the car.
