The 10.5″ 14 bolt full floating (full floater/FF/floater) is one of the toughest rear axles installed in the GMT400 platform. Its capacity far exceeds what most of the trucks were rated at towing and payload. These axles can be found in C/K 2500 and 3500 pickups, Cab & Chassis Trucks, and C/K2500 Suburbans. This is NOT the 14 bolt semi-float found in many lighter duty applications! The can easily be identified by the massive 14 bolt octagonal rear cover, and the full floating hubs.
All FF 14 bolts in GMT400’s will be 8×6.5″ 8 lug. It was available with either an open differential, or the Eaton Automatic Locking Differential (RPO G80). There a many different widths for the 14 bolt, Mostly based on different combinations of hubs and housings. I will try to list the most common ones.
If you are unfamiliar with the meaning of a “full-floating” vs. a “semi-floating” axle, here is a short explanation. Full floating axles, in general, can carrier more weight due to the fact the the vehicle is supported by a separate hub and bearings at the wheel end. The axle shaft itself is only used to transmit drive power to the wheel, it does not support the vehicles weight. In a semi float axle, the axle shaft has to do double duty of holding the vehicle weight, and transmitting power to the wheels.
Also, in full float applications, a broken axle will not lead to the wheel potentially exiting the vehicle!
General Specifications
| Applications | 1988-1999 Chevrolet/GMC C/K2500, C/K3500, Suburban |
| Type | Full Floating |
| GAWR | 8600lbs |
| Ring Gear | 10.5″ |
| Pinion Diameter | 1.75″ |
| Pinion Spline | 30 |
| Axle Spline | 30 |
| Carriers | Open Eaton Automatic Locking (RPO G80) |
| Carrier Break | 4.11 and below / 4.56 and above |
| Ratios | 3.42 (GU6) 3.73 (GT4) 4.10 (GT5) 4.56 (HC4) |
Dimensions
| SRW | DRW | C&C | |
| Width(WMS-WMS) | 67.5″ | 72″ | 63.5″ |
| Axle Tube | 3.25″ | 3.25″ | – |
| Lug Pattern | 8 x 6.5″ | 8 x 6.5″ | 8 x 6.5″ |
