gear ratio for auto and std tranny's - The 1947 - Present Chevrolet & GMC Truck Message Board Network

davidh · 05-03-2005, 01:35 AM

Please correct me if I am wrong. In 67-72's Weren't the standard rear end gears for a manual tranny 3.73's and for automatic's weren't they 3.08's.? Given this was the std equipment. I know other's were orderd different. I was thinking of putting a 3.08 gears behind a 67 c10 with a 3speed for gas mileage.

1969 GMC · 05-03-2005, 02:24 AM

Gearing depended on what engine was ordered or came stock, but you could always order optional ratios. It didn't matter what tranny was used.

Jason915 · 05-03-2005, 10:49 AM

I have seen alot of trucks and I'll tell you most trucks with V8's came with 3.08's unless it had an optional gear. Often 6cyl trucks had lower gears but it really depends on how the truck was ordered but there are more 3.08 trucks than anyting else.

Rod · 05-03-2005, 11:31 AM

You'd be better off assuming a 3.07 gear set in a 8 cyl and a 3.73 gear set in a 6 cyl as original equipment. It's not always the case, but it's a closer assumption. Manual trans really had not much to do with a truck having 3.73 gears or 3.07 gears.

3.07 gears behind a 6 cyl would still be drivable.

vfrdude · 05-03-2005, 12:35 PM

My truck came stock with a 3 speed manual trans, with 3.07 gears ( I believe cars had 3.08 gears). I ran the same gearing with the TH400. I've since installed a 700R4 and changed the gearing to 3.73's.

Bowtie67 · 05-03-2005, 12:46 PM

I dont think I would want a 3sp with 3.07 gears, maybe 3.42's. 1st gear is pretty high and taking off in first gear would be a PIA, if you tow anything or haul any heavy loads you will more likey burn a clutch out in no time.

05-03-2005, 01:35 AM	#1
davidh Senior Member Join Date: Feb 2004 Location: Ponca city now kingfisher Oklahoma Posts: 1,220	gear ratio for auto and std tranny's Please correct me if I am wrong. In 67-72's Weren't the standard rear end gears for a manual tranny 3.73's and for automatic's weren't they 3.08's.? Given this was the std equipment. I know other's were orderd different. I was thinking of putting a 3.08 gears behind a 67 c10 with a 3speed for gas mileage.

05-03-2005, 02:24 AM	#2
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	Gearing depended on what engine was ordered or came stock, but you could always order optional ratios. It didn't matter what tranny was used. __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

05-03-2005, 10:49 AM	#3
Jason915 Registered User Join Date: Jan 2005 Location: Colorado Springs Posts: 693	I have seen alot of trucks and I'll tell you most trucks with V8's came with 3.08's unless it had an optional gear. Often 6cyl trucks had lower gears but it really depends on how the truck was ordered but there are more 3.08 trucks than anyting else. __________________ 1971 GMC K1500 SWB Fleetside, 4" skyjacker softride and, 14 Bolt FF, HD Dana 44 4.10's 1970 K5 TBI conversion lifted etc SOLD 1968 C20 camper truck SOLD “To ban guns because criminals use them is to tell the innocent and law-abiding that their rights and liberties depend not on their own conduct, but on the conduct of the guilty and the lawless.” Jeff Snyder

05-03-2005, 11:31 AM	#4
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	You'd be better off assuming a 3.07 gear set in a 8 cyl and a 3.73 gear set in a 6 cyl as original equipment. It's not always the case, but it's a closer assumption. Manual trans really had not much to do with a truck having 3.73 gears or 3.07 gears. 3.07 gears behind a 6 cyl would still be drivable. __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

05-03-2005, 12:35 PM	#5
vfrdude Registered User Join Date: May 2002 Location: Oakley, Ca. USA Posts: 137	My truck came stock with a 3 speed manual trans, with 3.07 gears ( I believe cars had 3.08 gears). I ran the same gearing with the TH400. I've since installed a 700R4 and changed the gearing to 3.73's. __________________ Rudy Fierros '95 Honda VFR750F Used to have a '71 Chevy Stepside, Guards Red, Lowered 4" rear, 3" front, White Oak bed wood, 700R4 w/373 gears until some low life stole it!

05-03-2005, 12:46 PM	#6
Bowtie67 Registered User Join Date: Jan 2004 Location: NH Posts: 2,266	I dont think I would want a 3sp with 3.07 gears, maybe 3.42's. 1st gear is pretty high and taking off in first gear would be a PIA, if you tow anything or haul any heavy loads you will more likey burn a clutch out in no time. __________________ 1967 C10 - SWBSS Pro Street 427sbc, 700R4 & 4.10 Gears 1948 Chevy FleetMaster Coupe, LS1, (almost done) 1950 Chevy StyleLine Coupe 250/6 3x2 Dueces 2009 Toyota Tundra 1996 Harley RoadKing "I maybe getting old, but I can still burn rubber with the best of them"



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.