We offer a complete line of rear end parts for the GM 8.875" commonly refered to as the GM12 Bolt differential, this differential was utalized GM used this very popular differential in there full size Chevrolets, Chevelle, Chevy II, Camero, Nova, Oldsmobile F85 and GTO/Firebird Pontiac products starting in 1965 to 1972. Our inventory includes ring gear and pinion sets, including aftermarket and OE gear sets.

Having problems with your GM 12 bolt 8.875 inch rear end?   We offer a complete line of rear end parts for the GM 8.875" commonly refered to as the GM12 Bolt differential, this differential was utalized GM used this very popular differential in there full size Chevrolets, Chevelle, Chevy II, Camero, Nova, Oldsmobile F85 and GTO/Firebird Pontiac products starting in 1965 to 1972. Our inventory includes ring gear and pinion sets, including aftermarket and OE gear sets. We are able to supply axles, bearing overhaul kits, carriers, cases, spider and side gears. 

Positraction units we offer include Lockright, Powertrax no-Slip, Auburn, Detroit Lockers , and Eaton.  

Below is a list of the information and parts that we can supply for your GM Cheverolet 12 bolt Car applications:

Specifications are provided below to assist you in the identification and setup as well as torque spec's for your Chevy or GM 8.8755" differential:

GM 8.875" 12 Bolt Applications Model Year   Model Year Chevrolet 65-72   Firebird GTO 70-72 Chevy II 65-72   Nova 70-72 Chevelle 65-72   Olds F85 68-69 Camero 67-72       What differential ratio do you have? Need information on how to setup ring and pinion backlash Purchase your parts @ drivetrain.com and receive telephone access to experienced differential technician to assist you with installation, we help you solve the problem.

Specifications 10-7/8" 12 HOLES Oval Gasket Pattern RG Diameter 8.875" 12 3/8" X 24 RH Threaded Bolts PINION Diameter 1.625", 30 Spline CASE: 3.90 & Down, 4.10 Numerically Higher 8620 Material Heat-Treated Assembly Specifications: Cover Bolt Ft. Lbs. 20 Pinion Brg. Preload In. Lbs 20-25 Pinion Brg. Preload In. Lbs 10-15 Used Ring Gear Backlash .005-.009 Ring Gear Bolt to case Ft. Lbs. 90 Side Brg. Caps Ft. Lbs.

Chevrolet GM 8.875" Car Ring and Pinion Sets Differential Products

GM 8.875" 12 Bolt Ring Gear and Pinon Sets
Part Number	OE Number	Ratio	Teeth	Price
G888308		3.08	40-13	$337.50	Ring Gear Backlash Setup tool Your Cost $48.98 + S&H.
G888342		3.42	41-12	$210.00
G888355		3.55	39-11	$210.00
G888373		3.73	41-11	$210.00
G888390	Series 4 Case Thin Gear	3.90	39-10	$220.00
G888411		4.11	41-10	$210.00
G888411X		4.11	41-10	$220.00
G888430		4.30	43-10	$220.00
G888456		4.56	41-9	$220.00
G888456X		4.56	41-9	$220.00
G888488		4.88	39-8	$220.00
G888488X		4.88	39-8	$220.00
G888514		5.14	36-7	$220.00
G888538		5.38	43-8	$346.91
G888557		5.57	39-7	$346.91
G888586		5.86	41-7	$346.91
G888614		6.14	43-7	$346.91
X= Fits 3.07 - 3.73 Case