This is the well known “10 bolt”, so named for the number of bolts on the rear cover. The majority of C/K1500 trucks were equipped with this rear axle. Not to be confused with the passenger car 8.5″ differential, or the various other 10 bolts, the truck version is significantly stronger. It contains 30 spline axles and a larger ring gear and pinion shaft.
In GMT400’s, it was available with either an open differential, or the Eaton Automatic Locking Differential (RPO G80). The 2WD and 4WD trucks had different axle widths, 4WD being wider. Refer to the charts below for measurements.
General Specifications
| Applications | 1988-1999 Chevrolet/GMC C/K1500, Suburban, Tahoe, Yukon, Blazer |
| Type | Semi floating, c-clip |
| GAWR | 4800lbs |
| Ring Gear | 8.50″ |
| Pinion Diameter | 1.625″ |
| Pinion Spline | 30 |
| Axle Spline | 30 |
| Carriers | Open Eaton Automatic Locking (RPO G80) |
| Ratios | 3.08 (GU4) 3.23 (GU5) 3.42 (GU6) 3.73 (GT4) 4.10 (GT5) |
Dimensions
| 2WD | 4WD | |
| Width(WMS-WMS) | 65″ | 68″ |
| Spring to Spring | 47″ | 47″ |
| Axle Tube | 3.0″ | 3.0″ |
| Lug Pattern | 5×5″ | 6 x 5.5″ |
