Originally Posted By: bdcardinal
That being said, our tech has and will only use the Rotunda one for an 8.8
Easily the best tool to set up gearsets. Used that gauge tube/pinion depth set for more than a hundred 8.8 and 7.5" diffs, and never a problem, at least related to pinion depth. Horrendously expensive to have the whole set. My old dealership went out of business recently, too bad it was 12 years after I left there or I might have had a gauge set cheap.
Random stuff- The main thing the pinion shim compensates for is machining variance in the axle housing. FoMoCo gearsets, and rear bearings/races are always (in my experience) machined to a very fine tolerance regarding pinion depth. Long story short, using Ford gearsets, the depth shim that came out with the old pinion, is generally really close to what you need to get the right contact pattern. No experience with aftermarket depth gauge sets.
You will need a decent dial indicator to ck backlash, as well as an assortment of side shims. OEM side shims- use either a brass or plastic hammer to "tap" them in as a steel head hammer will shatter them like glass.
Torque wrench- the easiest way to torque a pinion nut is to use a small dial indicator torque wrench (inch/lbs) to set up rotational torque. After the first few sets of gears, I never even bothered with a big torque wrench on the pinion nut. I used an impact, snugged the pinion nut up until there was no play in the pinion, then switched to the little torque wrench with the dial indicator and checked the "drag" Something like 18 to 20 inch/lbs with new bearings lightly lubed. Bump the pinion nut with your impact and check it repeatedly with your torque wrench to sneak up on the proper rotational torque/drag, and you are good to go. All of the above assumes a NEW crush sleeve.
People are afraid of setting up diffs......voodoo! I get it. It is a PITA when you get one together and it whines, happened to me on a GM 10 bolt in a van. Lesson- don't set up another OEMs diff the way you set up a Ford Diff. Except for the smell of gear lube, I never had problems in the shop. Some diffs require a "case spreader" which is another consideration. Take your time, double check your work, be sure to put drag on the ring gear when checking your pattern (don't forget the coast side). Zinc heatsink grease will work for marking compound.