what color gear
Thread Starter
Instructor
Joined: Jul 2003
Posts: 213
Likes: 1
From: zanesville ohio
what color gear
New to this forum and have asked in another forum with no luck. Can someone tell me what color gear I should use in my 77 vette TH350 trans.? Just had the differential gears changed from 3.08s to 3.55s.My old trans.gears are green (drive gear) red (driven) and using stock 2.25/70-15 tires. Just thought while car is still up on stands and every thing is removed from trans back now would be easier if i need to pull the tail houseing off (if drive gear needs changed) Thanks jw
Melting Slicks
Joined: Oct 1999
Posts: 2,581
Likes: 14
From: Tolar Texas
Try using the calculation at the bottom of this 4L60 speedo calibration guide. I'm not absolutely certain but I don't think this calculation is tied specifically to the 4L60. Test it out by calculating your old setup to see if the answers match the existing drive and driven gears.
Please let us know your results.
Mike
Please let us know your results.
Mike
Team Owner
Joined: Aug 2000
Posts: 21,457
Likes: 463
From: Massillon,Ohio USA
2020 C3 of the Year Finalist - Unmodified
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St. Jude Donor '08-'09-'10-'11-'12
jw, According to my '53-'81 GM Corvette Catalog, all 1976 & 1977 Corvettes with 3.08, 3.36, 3.55 & 3.70 gears all took the same drive gear #8623310, however the book also shows that a 3.08 rear end car should've came with a 35 tooth Pink driven gear(may be the plastic is faded and it is really pink or has red tranny fluid on it 
). Also, according to the chart, since all the above named ratios took the same #8623310 drive gear, a 3.55 ratio would now take the #1362048 Black 40 tooth gear.
How many teeth are on your "red" gear-my book shows that as a 21 tooth gear.
). Also, according to the chart, since all the above named ratios took the same #8623310 drive gear, a 3.55 ratio would now take the #1362048 Black 40 tooth gear. How many teeth are on your "red" gear-my book shows that as a 21 tooth gear.
Le Mans Master
Joined: Jan 2004
Posts: 8,295
Likes: 30
From: one night in Bangkok you are never lonely
Originally Posted by Paul Borowski
jw, According to my '53-'81 GM Corvette Catalog, all 1976 & 1977 Corvettes with 3.08, 3.36, 3.55 & 3.70 gears all took the same drive gear #8623310, however the book also shows that a 3.08 rear end car should've came with a 35 tooth Pink driven gear(may be the plastic is faded and it is really pink or has red tranny fluid on it ). Also, according to the chart, since all the above named ratios took the same #8623310 drive gear, a 3.55 ratio would now take the #1362048 Black 40 tooth gear.
How many teeth are on your "red" gear-my book shows that as a 21 tooth gear.
). Also, according to the chart, since all the above named ratios took the same #8623310 drive gear, a 3.55 ratio would now take the #1362048 Black 40 tooth gear. How many teeth are on your "red" gear-my book shows that as a 21 tooth gear.
Paul
What color gear should my 81 have with 4 speed 3.73 rear gears stock tires?
Team Owner
Joined: Aug 2000
Posts: 21,457
Likes: 463
From: Massillon,Ohio USA
2020 C3 of the Year Finalist - Unmodified
Cruise-In VI Veteran
St. Jude Donor '08-'09-'10-'11-'12
Originally Posted by Bangkok Dean
Paul
What color gear should my 81 have with 4 speed 3.73 rear gears stock tires?
What color gear should my 81 have with 4 speed 3.73 rear gears stock tires?
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Le Mans Master
Joined: Jan 2004
Posts: 8,295
Likes: 30
From: one night in Bangkok you are never lonely
Originally Posted by Paul Borowski
Dean, since no '81 came stock with a 3.73, it won't show it, so I did however look at the chart for '79 which could have come with as high as a 3.70 rear gear. The driven gear(one at the end of the cable)for a '79 3.70 rearend was a #3987920, which was a 20 tooth "Blue" gear.
Thanks for the info I will try to order a new gear.
