Precision Gear - GM 8 7/8" Truck Ring and Pinion Gear Sets

Ring Gear Diameter:
Pinion Shaft Diameter:
Ring Gear Bolts:
Right Hand Threads:
Pinion Splines:
Cover Bolts:

8 7/8"
1.438"
12
3/8" x 24
30
12

Model	Year
K10, K15	64-81
C10, C15	64-81
G10, G15	64-81
G20, G25	69-78

Ratio	Teeth	Part #
3.08	40-13	GM12/308
3.42	41-12	GM12/342
3.73	41-11	GM12/373
3.73+	41-11	GM12/373+
4.10	41-10	GM12/410
4.10+	41-10	GM12/410+
4.56	41-9	GM12/456
4.56+	41-9	GM12/456+
4.88	39-8	GM12/488
4.88+	39-8	GM12/488+

.................................................

+ Gear sets are designed "extra thick" to be used with a 2.76 thru 3.42 case.

Installation Kits	Part #
Master Installation Kts
	GM12/MOKITT
Installation Kits
	GM12/KITT
Mini Installation Kits
	GM12/MKITT
Pinion Bearing Set-Up Kit
	PINSU2

Tech Note:
When replacing 3.42 and numerically lower ratio gear sets with a 3.73 or higher gear, an extra thick ring gear must be used or the case must be changed to a 3.73 and higher case.

• GM 7 1/4"
• GM 7 1/2" 
  (GM 7 5/8")
• GM 7 3/4"
  Borg-Warner
• GM 8.2" Chevy
• GM 8 1/4" IFS
• GM 8 1/2"
• GM 8 7/8" Car
• GM 8 7/8" Truck
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• GM 9 1/2"
• GM 10 1/2"
• GM 11 1/2"