[Formulajones]

Yeah they "kinda" work.

Basically the idea with those is you have to hold it or bolt it to the bearing cap mating surface and measure from there to the face of the pinion. It's not quite as accurate this way and you'll find you'll triple check your measurement and get 3 different readings. It gets a little frustrating. I'm talking maybe a couple thou one way or the other but it's enough to make you second guess. You'll also find that if you rotate the mount slightly while it's on the rearend mating surface it also changes the readings and that's even more frustrating. That surface isn't perfect and that's where this style of tool has it's issues. Every time you remove it to make a pinion adjustment there is no guarantee it's in the same spot giving you the same reading as before, in fact I'll guarantee that'll change every time making you chase your tail, LOL. One problem with it is that main cap bolt it torqued to 60-65 ft lbs. What that does to the housing, even when you can't see it with the naked eye, is it pulls the metal out slightly around the threads. It's distorted, and you're now trying to bolt that tool to it, you'll find it rocks around a bit, and there is no way to really make that surface perfectly flat again, can't get a file on it, it just is what it is.

The other issue, and you can measure for this, is that the break (parting line) between the housing surface and the bearing cap may not be exactly center. It can be .002-.003" either way. It's supposed to be, or assumed to be exactly half but that's not always the case. Those are reasons why the donut style pinion gauges (the expensive ones) are more accurate as it takes all these variables out of the equation.