K 3500 Truck 4WD V8-5.7L VIN R (1998)
Ring Gear: Technical Service Bulletins
Rear Axle Ring & Pinion Gear Sets - 2 Cut vs. 5 Cut
File In Section: 04 - Driveline Axle
Bulletin No.: 00-04-20-OO1A
Date: November, 2001
INFORMATION
Subject:
2-Cut vs. 5-Cut Rear Axle Ring and Pinion Gearsets
Models:
2002 and Prior Chevrolet and GMC Light Duty Truck Models
1999-2000 Cadillac Escalade
2002 Cadillac Escalade
With 8.6 Inch Ring Gear (3.08, 3.42, 3.73 or 4.10 Ratio) Rear Axles
This bulletin is being revised to add model, parts and text information. Please discard Corporate Bulletin Number 00-04-20-001 (Section 04 - Driveline
Axle).
The purpose of this bulletin is to inform technicians of the difference between a 2-cut and a 5-cut ring and pinion gearset pattern (manufacturing process
only). Current technical publications are for 5-cut gearsets. However, both 2-cut and 5-cut gearsets are available in service and production.
Technicians report that they are unable to properly set the ring and pinion and get the same pattern as the gear that was removed. After the vehicle was
driven, the vehicle exhibited severe rear axle noise from trying to match the pattern of a 5-cut gearset.
The 2-cut gearsets meet all manufacturing specifications and should be considered quality gearsets. The "set-up" condition stated above might have been
the result of one of the two following possibilities:
The technician is trying to make a 2-cut gearset pattern conform to the same build pattern as a 5-cut gearset. Because of the manufacturing differences,
the build pattern on 2-cut and 5-cut gearsets is significantly different. The most accurate way to tell the difference between a 2-cut and a 5-cut gearset is
to look at the toe to heel tooth height of the ring gear.
The 2-cut gearsets have a natural "bias" condition in the patterns. Bias shows as a slanted pattern (1) on the gearset when rolled with marking compound.
On a 2-cut gearset, the height of the tooth remains constant from the tooth's toe to heel. When attempting to turn a biased pattern into a square pattern by
altering the pinion shim thickness and/or backlash, a 2-cut gearset will become noisy.
