QT1099 Differential Master Bearings
for Dana 70HD and 80 Axles Also known as Dummy Bearings, these precision machined, solid steel tools are used in place of real bearings to easily determine the shim thickness required for correct backlash and differential bearing preload. Made to be a slip fit on your differential so you can slide the differential, side to side to determine the overall shim distance and the ring gear side distance with a dial indicator. With those two figures you can easily calculate the opposite side shim pack (Order TM4400
for Service Procedures). Made for the 4.25" OD bearings on all Dana-Spicer Model 70HD and Dana-Spicer Model 80 series axles. Will not work on Dana-Spicer Model 60 or 70 axles, which have 3-13/16" diameter bearing cups and use QT1098
Master Bearings. Made in U.S.A.
Dan the Gear Man® Tech Note: If you are installing a new gear set and/or a new differential you will need Master Bearings. If one or both of your diff bearings spun on the differential and tore the shims, you will also need these tools to determine the correct shim packs. (This is very common especially with Diesel trucks). However, if you are just doing a simple re-bearing job on a factory setup axle using OE Quality Bearings (See QU50402, QU50403 on the Dana Rear Axle Page) and your housing is not worn, you probably will not need Master Bearings.