Ballenxj wrote:
Griff in Fairbanks wrote:
The Dana 70 was standard equipment and is, in my opinion, an ideal rear axle, even considering drum vs disc rear brakes. Keep it topped of with gear lube and replace bearings and seals every few hundred thousand miles and it will last millions of miles and a century or more.
My 1983 Sportscoach on a P30 chassis had disc brakes on the differential. For the life of me I don't know what differential it was, all I know is it was big.
The differential is the "pumpkin" near the middle of the rear axle, and/or front axle on four-, front-. and all-wheel drive vehicles.
It's primary purpose is to allow the wheels to turn at different (i.e., differential) speeds while cornering. Without it, one of the tires on a drive axle would have to "scuff" while going around a corner.
Many older vehicles had a drum or disc brake on the driveshaft, either on the transmission or differential end, to serve as a "parking" brake. These are often referred to as driveline brakes. Most (all?) Mopar transmissions up until the early '70s had a small drum brake on the back end of the transmission.
Extremely important safety warning: Driveline brakes, as well as the internal parking pawl on most modern transmissions, ONLY "lock" the wheels on the drive axle when all tires on BOTH sides have a firm grip on the ground. Due to the function of the differential, the wheel(s) on one side can, and WILL, turn when the wheel(s) on the other side are jacked off the ground or on a slippery surface.
This is the primary reason safety experts tell you to chock the tires when changing a tire or working on the vehicle.
