3.07 gears???? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

78-5.3 · 01-01-2010, 06:22 PM

i got a 12 bolt given to me today out of a truck i count the ring and pinion and got 43-14 its also stamped 43-14 if im correct this is 3.07 ??? i thought these trucks had 3.08?

3r!c84 · 01-01-2010, 07:10 PM

round it up?

78-5.3 · 01-01-2010, 07:27 PM

my question is why is there no 3.07 gear set but a 3.08 ? why was it called a 3.08 set instead of 3.07? if it works out to be 3.07

cableguy0 · 01-01-2010, 07:58 PM

hmm thats odd. i know they count out to almost exactly 3.07 not sure why the factory called em 3.08. the math dont work. you have stock gears

BLE 'BURBAN · 01-01-2010, 07:59 PM

My old '74 heavy 1/2ton had 3:07 gears in a 12 bolt rear end. Still got the axle out back buried under a tarp/snow&ice.

3r!c84 · 01-01-2010, 08:21 PM

maby 3.08 where only in 10bolt rearends,and 3.07 in 12bolts

vern350 · 01-01-2010, 08:25 PM

i think the 3.07 in 12 bolts and 3.08s in 10 bolts is a good guess!

3r!c84 · 01-01-2010, 08:26 PM

did i win? did i guess right

3r!c84 · 01-01-2010, 08:33 PM

found it out

12 and 10 bolts have diffrent set ups like 4.11 and 4.10

http://www.chevellestuff.com/1969/rear_axle.htm

KQQL IT · 01-01-2010, 08:34 PM

^^^ great story anyways

**N2TRUX** · 01-01-2010, 09:14 PM

Quote:

Originally Posted by vern350

i think the 3.07 in 12 bolts and 3.08s in 10 bolts is a good guess!

Not correct though. My 77 Cheyenne has a 12 bolt with 3.08 gears from the factory.

cableguy0 · 01-01-2010, 09:17 PM

the tooth count will still be 43/14 which mathematically is 3.07 regardless what the sticker says

LONGHAIR · 01-01-2010, 09:22 PM

I was always under the impression that it was 3.07 = Truck, and 3.08 = Car

3r!c84 · 01-01-2010, 09:26 PM

(:

flamingbig10 · 01-01-2010, 10:47 PM

there was 3.08, 3.42, 3.73,4.11
http://www.lmctruck.com/icatalog/cc/full.aspx?Page=150

Pyrotechnic · 01-01-2010, 11:08 PM

Maybe it's just a matter of what rolls off the tongue better ?

Maybe the small number differences was used to help differentiate between car and truck, or 10 and 12 bolt gears, but the system was later dropped ?

For 70's trucks I've seen 3.07, 3.40, and 4.10 printed in a sales brochure. My glove box sticker says 3.40.

karl · 01-02-2010, 12:37 AM

my 12 bolt has a factory 3.07. wish it were 3.42

78-5.3 · 01-02-2010, 11:26 AM

Quote:

Originally Posted by cableguy0

the tooth count will still be 43/14 which mathematically is 3.07 regardless what the sticker says

that is what mine counted 43/14 i went to buy it because the guy told me it was 3.73 i counted it and it was 43/14 he gave the rear end to me!!!
ALSO is there a differance between the 2WD-4WD rear ends ive read the axles where interchanged ?????

MTCK · 01-02-2010, 04:44 PM

This made me curious since my K10 has 3.08 gears in it. Looking at the aftermarket parts available, 3.08 is what you will find in the rear 10/12 bolt (40/13 tooth count) and the dana 44 front will have the 3.07 (43/14). The true difference in ratio is only 0.0055. If folks are counting 43/14 in their rear end I'd say they have 3.07 gears from the factory, but only 3.08 are available from the aftermarket now? (summit and randy's R&P)

lnwlfbsktbll · 01-04-2010, 08:56 PM

I picked up a 12 bolt from a '77 truck to go in my '87 and the axle code shows it has 3.07s

78-5.3 · 01-05-2010, 08:50 AM

does anyone know what i need to change my gears to either 3.73 or 4.10 they are 3.07 at the moment do i just need the ring and pinion set or a carrier too? its open and im leavng it that way !!! i know there other need parts to buy ?

68 TT · 01-05-2010, 09:25 AM

Quote:

Originally Posted by 3r!c84

maby 3.08 where only in 10bolt rearends,and 3.07 in 12bolts

They had both in the car 12-bolt so they probably did the same thing in the truck. A 3.07 gear is on a 2-series carrier and the 3.08 is on a 3-series carrier in the car 12-bolt so probably the same in the truck version.

Don't ask me why they did that but they did.

68 TT · 01-05-2010, 09:28 AM

Quote:

Originally Posted by 78-5.3

does anyone know what i need to change my gears to either 3.73 or 4.10 they are 3.07 at the moment do i just need the ring and pinion set or a carrier too? its open and im leavng it that way !!! i know there other need parts to buy ?

If is is a 2-series carrier like I think it is then you will need a different carrier too. If they break it down like the car 12-bolt carriers you will need a 3-series for 3.73's and a 4-series for 4.10's unless you run special thick gears on a 3-series carrier then you can get 4.10's on the 3-series. Can't get 3.73's on a 4-series carrier.

jrsavoie · 01-05-2010, 09:40 AM

What does it cost to switch gears in a 4x4 95 Tahoe. I would like to go from a 3.73 to a 3.42 or 3.07.
I've never messed with differentials. Is this best left to an exper? Any good shops for this near Illiana?

78-5.3 · 01-05-2010, 10:39 AM

Quote:

Originally Posted by 68 TT

If is is a 2-series carrier like I think it is then you will need a different carrier too. If they break it down like the car 12-bolt carriers you will need a 3-series for 3.73's and a 4-series for 4.10's unless you run special thick gears on a 3-series carrier then you can get 4.10's on the 3-series. Can't get 3.73's on a 4-series carrier.

understand !!12 bolts are alot of hassle compared to a 9" i think i might start looking for a nine inch thats been narrowed down too around an s10 width for my future 4 bar set up i just wanna run lower gears till then!! these diesel gears are terrible

01-01-2010, 06:22 PM	#1
78-5.3 Registered User Join Date: Oct 2009 Location: Waterboro ,MAINE Posts: 547	3.07 gears???? i got a 12 bolt given to me today out of a truck i count the ring and pinion and got 43-14 its also stamped 43-14 if im correct this is 3.07 ??? i thought these trucks had 3.08? Last edited by 78-5.3; 01-01-2010 at 07:17 PM.

01-01-2010, 07:10 PM	#2
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: 3.07 gears???? round it up? __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

01-01-2010, 07:27 PM	#3
78-5.3 Registered User Join Date: Oct 2009 Location: Waterboro ,MAINE Posts: 547	Re: 3.07 gears???? my question is why is there no 3.07 gear set but a 3.08 ? why was it called a 3.08 set instead of 3.07? if it works out to be 3.07

01-01-2010, 07:58 PM	#4
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	Re: 3.07 gears???? hmm thats odd. i know they count out to almost exactly 3.07 not sure why the factory called em 3.08. the math dont work. you have stock gears __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

01-01-2010, 07:59 PM	#5
BLE 'BURBAN In the Forgotten far North. Join Date: Jul 2007 Location: Anchorage, Alaska Posts: 2,627	Re: 3.07 gears???? My old '74 heavy 1/2ton had 3:07 gears in a 12 bolt rear end. Still got the axle out back buried under a tarp/snow&ice. __________________ 1987 R3500 CREW CAB DUALLY (BIG RED)Acquired 06/12/2015 1990 chevy suburban V2500 5.7L My cluster Mods-Nov 2007 overhead console Stereo install Round 2 Aug 2009 Heated/turn signal mirror upgrade

01-01-2010, 08:21 PM	#6
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: 3.07 gears???? maby 3.08 where only in 10bolt rearends,and 3.07 in 12bolts __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

01-01-2010, 08:25 PM	#7
vern350 like a rock Join Date: Nov 2004 Location: Ontario, Canada Posts: 517	Re: 3.07 gears???? i think the 3.07 in 12 bolts and 3.08s in 10 bolts is a good guess!

01-01-2010, 08:26 PM	#8
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: 3.07 gears???? did i win? did i guess right __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

01-01-2010, 08:33 PM	#9
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: 3.07 gears???? found it out 12 and 10 bolts have diffrent set ups like 4.11 and 4.10 http://www.chevellestuff.com/1969/rear_axle.htm __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

01-01-2010, 08:34 PM	#10
KQQL IT At the body shop. Join Date: Aug 2009 Location: Land of fruits and nuts. Posts: 5,199	Re: 3.07 gears???? ^^^ great story anyways __________________ " That didnt make it any newer " " Dont antique the equipment "

01-01-2010, 09:17 PM	#12
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	Re: 3.07 gears???? the tooth count will still be 43/14 which mathematically is 3.07 regardless what the sticker says __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

01-01-2010, 09:26 PM	#14
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: 3.07 gears???? (: __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90 Last edited by 3r!c84; 01-01-2010 at 10:47 PM.

01-01-2010, 10:47 PM	#15
flamingbig10 6.0 powered square Join Date: Feb 2008 Location: Mesquite texas Posts: 3,459	Re: 3.07 gears???? there was 3.08, 3.42, 3.73,4.11 http://www.lmctruck.com/icatalog/cc/full.aspx?Page=150 __________________ Aaron 1980 c-10 short bed lowered, cammed 6.0, 4l80e 3600 stall, smp tune, wilwoods, and flames best time so far best et 7.86 @87 on motor 7.57 90 on a 75 shot Build http://67-72chevytrucks.com/vboard/s...d.php?t=283326 Last edited by flamingbig10; 01-01-2010 at 10:58 PM.

01-01-2010, 11:08 PM	#16
Pyrotechnic Registered User Join Date: Feb 2007 Location: Austin, TX Posts: 3,930	Re: 3.07 gears???? Maybe it's just a matter of what rolls off the tongue better ? Maybe the small number differences was used to help differentiate between car and truck, or 10 and 12 bolt gears, but the system was later dropped ? For 70's trucks I've seen 3.07, 3.40, and 4.10 printed in a sales brochure. My glove box sticker says 3.40. __________________ 1977 GMC Sierra Grande

01-02-2010, 12:37 AM	#17
karl Registered User Join Date: Dec 2004 Location: grand terrace , caifornia Posts: 338	Re: 3.07 gears???? my 12 bolt has a factory 3.07. wish it were 3.42



Register or Log In To remove these advertisements.

01-02-2010, 04:44 PM	#19
MTCK Registered User Join Date: Dec 2009 Location: Fairbanks, AK Posts: 1,830	Re: 3.07 gears???? This made me curious since my K10 has 3.08 gears in it. Looking at the aftermarket parts available, 3.08 is what you will find in the rear 10/12 bolt (40/13 tooth count) and the dana 44 front will have the 3.07 (43/14). The true difference in ratio is only 0.0055. If folks are counting 43/14 in their rear end I'd say they have 3.07 gears from the factory, but only 3.08 are available from the aftermarket now? (summit and randy's R&P) __________________ -Marcus 1991 V3500 L29 454 4L80E NP205 D60/14 Bolt 4.56's 1984 K30 292 TH400 NP205 D60/14 Bolt 4.56's flat bed 7'6" Meyer Plow 2022 Silverado 3500 L8T Project Daily Driver Project Heavy Hauler Project Plow Truck

01-04-2010, 08:56 PM	#20
lnwlfbsktbll Registered User Join Date: Mar 2009 Location: midwest city, OK Posts: 95	Re: 3.07 gears???? I picked up a 12 bolt from a '77 truck to go in my '87 and the axle code shows it has 3.07s __________________ '87 SWB GMC LY6/6L90E '70 JEEP CJ5... My new toy '06 Hyundai Accent... DD Build thread located at http://67-72chevytrucks.com/vboard/s...5708&posted=1#

01-05-2010, 08:50 AM	#21
78-5.3 Registered User Join Date: Oct 2009 Location: Waterboro ,MAINE Posts: 547	Re: 3.07 gears???? does anyone know what i need to change my gears to either 3.73 or 4.10 they are 3.07 at the moment do i just need the ring and pinion set or a carrier too? its open and im leavng it that way !!! i know there other need parts to buy ?

01-05-2010, 09:40 AM	#24
jrsavoie Registered User Join Date: Jan 2010 Location: Clifton, Illinois Posts: 93	Re: 3.07 gears???? What does it cost to switch gears in a 4x4 95 Tahoe. I would like to go from a 3.73 to a 3.42 or 3.07. I've never messed with differentials. Is this best left to an exper? Any good shops for this near Illiana?

Register or Log In To remove these advertisements.