gear ratios - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tphsmith · 01-08-2007, 08:45 PM

ok this is like umteen times I have asked these questions but lets look at it at a diffrent angle, can someone explain why there are so many gear ranges and what were the intentions for all the diffrent ranges. My truck was built in canada with an inline 6 in it. did it have a column shift? i dont know this but tonight I dropped the rear end cover and seen the gears are stamped 14:43 so off a chart I see this would be 3:07 gears is this correct?. and now I want to put a LT1 Motor with a 700R for a transmission and now hopefully this can be explained to me what these gears mean and hopefully someone will sugest a gear range to put in this 72 swb and I plan on running 17 inch wheels on the truck so all the feedback i can get will realy be appreciated. so for being so windy but this gear ratio thing Id like explained thank everyone in advance

Longhorn Man · 01-08-2007, 09:49 PM

you are right, you have a 3.07 gear. That is the freeway gear of the bunch.
You ask why all the gear options... it all depends on what the original owner was going to do with it. If it was a farm truck that hardly ever saw pavement, and never saw the high side of 40MPH, then you could get what ever gears you wanted...and the 3.73 or even 4.10 was great for pulling anything around the farm. But, anyone with 4.10 gears will tell you (myself included) they SUCK on the freeway. A 3.07 would keep the RPMs nice and low (low by 1960's standards) and you could drive your truck cross country at 75 MPH and not worry about the engine buzzing to death.
As for your situation, I recomend locating a 3.73 rear axle and swapping the whole thing out. Your 3.07 is desirable to someone without overdrive, and you could swap even up no problem.

tphsmith · 01-08-2007, 10:27 PM

what does it mean by series 4 or series 3? can you help me here to understand what that is all about?

Longhorn Man · 01-08-2007, 10:32 PM

someone else will have to help... think of them as size instead of serise. with one you can have gear ratio X up to X... then you need the next size for X to X

tphsmith · 01-09-2007, 09:03 PM

ttt whats it mean by "series" can anybody explain. seems to be alot of info here on dif cases but still I dont know what it means by series

01-08-2007, 08:45 PM	#1
tphsmith still buypickupparts Join Date: Sep 2003 Location: charlotte Posts: 637	gear ratios ok this is like umteen times I have asked these questions but lets look at it at a diffrent angle, can someone explain why there are so many gear ranges and what were the intentions for all the diffrent ranges. My truck was built in canada with an inline 6 in it. did it have a column shift? i dont know this but tonight I dropped the rear end cover and seen the gears are stamped 14:43 so off a chart I see this would be 3:07 gears is this correct?. and now I want to put a LT1 Motor with a 700R for a transmission and now hopefully this can be explained to me what these gears mean and hopefully someone will sugest a gear range to put in this 72 swb and I plan on running 17 inch wheels on the truck so all the feedback i can get will realy be appreciated. so for being so windy but this gear ratio thing Id like explained thank everyone in advance __________________ Its Gonna be a Great Day, I woke up this Morning. 72 SWB Fleetside freshly painted. putting a 94 LT1 with 700R4 tranny lowered 4 in the front 6 in the back 81 chevy half ton 350 89 Silverado 4x4 going ta church truck

01-08-2007, 09:49 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: gear ratios you are right, you have a 3.07 gear. That is the freeway gear of the bunch. You ask why all the gear options... it all depends on what the original owner was going to do with it. If it was a farm truck that hardly ever saw pavement, and never saw the high side of 40MPH, then you could get what ever gears you wanted...and the 3.73 or even 4.10 was great for pulling anything around the farm. But, anyone with 4.10 gears will tell you (myself included) they SUCK on the freeway. A 3.07 would keep the RPMs nice and low (low by 1960's standards) and you could drive your truck cross country at 75 MPH and not worry about the engine buzzing to death. As for your situation, I recomend locating a 3.73 rear axle and swapping the whole thing out. Your 3.07 is desirable to someone without overdrive, and you could swap even up no problem.

01-08-2007, 10:27 PM	#3
tphsmith still buypickupparts Join Date: Sep 2003 Location: charlotte Posts: 637	Re: gear ratios what does it mean by series 4 or series 3? can you help me here to understand what that is all about? __________________ Its Gonna be a Great Day, I woke up this Morning. 72 SWB Fleetside freshly painted. putting a 94 LT1 with 700R4 tranny lowered 4 in the front 6 in the back 81 chevy half ton 350 89 Silverado 4x4 going ta church truck

01-08-2007, 10:32 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: gear ratios someone else will have to help... think of them as size instead of serise. with one you can have gear ratio X up to X... then you need the next size for X to X

01-09-2007, 09:03 PM	#5
tphsmith still buypickupparts Join Date: Sep 2003 Location: charlotte Posts: 637	Re: gear ratios ttt whats it mean by "series" can anybody explain. seems to be alot of info here on dif cases but still I dont know what it means by series __________________ Its Gonna be a Great Day, I woke up this Morning. 72 SWB Fleetside freshly painted. putting a 94 LT1 with 700R4 tranny lowered 4 in the front 6 in the back 81 chevy half ton 350 89 Silverado 4x4 going ta church truck

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