I'm looking to bump up my gears to 4.10 or possibly 4.30 and even though I'm about to drop $900 on gears and equipment to do both axles, I'm not thrilled about the idea of having my truck at shop for a few days and $500+ later to have them installed. 4.10s with my 35s will "rezero" my speedometer but I know a lot of guys prefer 4.30s for towing. I'm leaning more toward 4.10s because I do eventually want to drop down the lift and go with 19.5s. I've lived with these 3.73s long enough, regular everyday driving is wonderful, but as soon as I get some weight in my trailer or try to pull my dad's 46' race trailer it's very frustrating losing so many RPMs when I shift and bogging at the starts because of how tall the gears are. I've done gears on my own once or twice in the past...about 10 years ago on a Ford 9". So this will be the first time on axles without a drop-out 3rd member. I do remember that setting the pinion depth was the mother of the job, putting it all together and torqued down just to pull it apart and reshim it . The lash was the easy bit. What's the process for our axles? Any specific tools? What size nut is on the pinion? I presume 1350 U-joints? Same front and rear?

 

With time on your side, sometimes you can find a steal-of-a-deal on used diffs in the ratio you need/want. Unless worn badly, the bearings can be renewed while keeping the stock shimming.

A crush sleeve eliminator (for rear diff) is a huge help when you have to trial & error your install multiple times.

It took me a long time to gear up with tools to do gears comfortably... 30-ton press, clamshell style bearing puller, case spreader (Dana diffs). I feel like I can tackle any diff now so long as I'm not in a rush.

 

I'll keep an eye out for used axles. I do have a bearing puller and a press (granted only a 10 ton bench-top, will that be enough?), I can see if some of my Jeep guys at work have a case spreader I can borrow.

Trying to figure out how high on the priority list this job needs to go, I have about 10-15° of driveshaft rotation worth of backlash which has me concerned. I haven't been able to find anywhere how much is acceptable. There is no side to side play and the yoke does not move in and out with this rotation at all. For the record, yes, I am SURE it is backlash and not the the u-joint because the yoke is tight with the shaft and rocks back and forth when rotating the driveshaft.

 

10-ton may not be enough for the rear. 10.5" carrier bearings are large.