Newbie Differential Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Leets · 06-11-2004, 04:11 PM

First off, I'm new to these trucks so please excuse the ignorance of my question. I tried doing a few searches but couldn't find what I was looking for. My girlfriend's dad has a 72 Chevy that now has a 454 with (I believe) a 4.10 rearend. The engine's built and puttin out plenty of torque so he no longer wants to use that rearend. He does a lot of freeway driving so he wants something that isn't as steep to get better mileage. Question is, what differentials came on the 72 and what are some direct replacement options we could find at any old junkyard for cheap? Thanks for the help.

1972ChevyGuy · 06-11-2004, 09:44 PM

3.07/8s came with as an option I beleive. Norm is 3.73 and 4.10/11. Aftermarket units you can get I believe you can get 3.55? (It's a 3.5*) Almost any truck 12 bolt with coils will bolt up. Car rear-ends are a little bit narrower.

Leets · 06-15-2004, 06:27 PM

Thanks for the reply. Did they all have 8-lug axles or was that year/model specific? If so, what models/years should I look for?

1972ChevyGuy · 06-15-2004, 07:23 PM

8 lug will be found on heavy duty trucks (3/4 ton, 1 ton) 67-to either 70 or 71 I beleive are 6 lug with drum brakes. 71-72 or maybe just 72, I'm not totally sure when they started going to 5 lug with disc brakes. 5 and 6 lug are found on 1/2 ton trucks. 5 lug will get you about the most wheel choices, there are good 6 and 8 luggers out there but IMO they cost a bit more.

DennyB · 09-02-2004, 12:27 PM

The 71 3/4 I had had 8 lugs.
I believe all the 67-72 3/4s were 8 lug.
The 71-72 1/2 tons was the switch to 5 lug and disc brakes

longhorn71 · 10-03-2004, 10:36 PM

all 3/4 tons have 8 bolt wheels and the bolt pattern is not changed to is day.the 67-72 trucks were the last with coils springs in the rear

krue · 10-03-2004, 10:46 PM

Welcome to the board from South Mississippi! Post some pics of the truck.

06-11-2004, 04:11 PM	#1
Leets Registered User Join Date: Jun 2004 Location: OC, California Posts: 2	Newbie Differential Question First off, I'm new to these trucks so please excuse the ignorance of my question. I tried doing a few searches but couldn't find what I was looking for. My girlfriend's dad has a 72 Chevy that now has a 454 with (I believe) a 4.10 rearend. The engine's built and puttin out plenty of torque so he no longer wants to use that rearend. He does a lot of freeway driving so he wants something that isn't as steep to get better mileage. Question is, what differentials came on the 72 and what are some direct replacement options we could find at any old junkyard for cheap? Thanks for the help.

06-15-2004, 07:23 PM	#4
1972ChevyGuy Registered User Join Date: Nov 2002 Location: Kannapolis, NC Posts: 552	8 lug will be found on heavy duty trucks (3/4 ton, 1 ton) 67-to either 70 or 71 I beleive are 6 lug with drum brakes. 71-72 or maybe just 72, I'm not totally sure when they started going to 5 lug with disc brakes. 5 and 6 lug are found on 1/2 ton trucks. 5 lug will get you about the most wheel choices, there are good 6 and 8 luggers out there but IMO they cost a bit more. Last edited by 1972ChevyGuy; 06-16-2004 at 08:07 PM.

09-02-2004, 12:27 PM	#5
DennyB Led Sled! Discs R 4 ME! Join Date: Jan 2001 Location: Toms River, NJ, USA (Transplanted Hoosier) Posts: 7,327	The 71 3/4 I had had 8 lugs. I believe all the 67-72 3/4s were 8 lug. The 71-72 1/2 tons was the switch to 5 lug and disc brakes __________________ "Never ride faster than your Angel can fly" I.M.O.M,W,J&C Patriot Guard Rider

10-03-2004, 10:46 PM	#7
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	Welcome to the board from South Mississippi! Post some pics of the truck. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

06-11-2004, 09:44 PM	#2
1972ChevyGuy Registered User Join Date: Nov 2002 Location: Kannapolis, NC Posts: 552	3.07/8s came with as an option I beleive. Norm is 3.73 and 4.10/11. Aftermarket units you can get I believe you can get 3.55? (It's a 3.5*) Almost any truck 12 bolt with coils will bolt up. Car rear-ends are a little bit narrower.

06-15-2004, 06:27 PM	#3
Leets Registered User Join Date: Jun 2004 Location: OC, California Posts: 2	Thanks for the reply. Did they all have 8-lug axles or was that year/model specific? If so, what models/years should I look for?

10-03-2004, 10:36 PM	#6
longhorn71 Senior Member Join Date: Sep 2004 Location: CANADA Posts: 1,681	all 3/4 tons have 8 bolt wheels and the bolt pattern is not changed to is day.the 67-72 trucks were the last with coils springs in the rear



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