USMC20yrs

I am looking into the 3.21 to 3.73 gear change on my 2013 JK "Next Gen" (D30/D44) axles. Along with sourcing the ring and pinion, do I also need to source new carriers? And if I later decide to go to 4.10s, will I need new carriers again?

stagedtrip

That's a waste of money going 3.21s to 3.73s. Just go 4.10s now if that's your end game, why pay that much for labor twice?
Semper

jadmt

your rear carrier is fine you will need a new front carrier. If you can find a good set of very low mileage take offs for cheap and find affordable labor it might be worth it but otherwise I would look at 4.10's or 4.56's. I was in the same boat. I had a 13 4 door with 3.21 and auto and started shopping to get 4.10's and in my area I was looking at over $2000 for parts and labor. I just traded and got a new Rubicon with 4.10's.

USMC20yrs

My end game is 3.73 with 33s. But who knows what the future holds; I may get a bug someday and decide to lift and up the tire size again. Since this is my daily driver, for now the 3.73/33 is where I'll be going. And since I'll be doing the install myself (and I'm retired) labor time is cheap (zero).

But, here is another question. I don't know what it comes with from the factory, but since I'm in there is a change to full synthetic a good call? And if so, how about a multi-grade. I know that Royal Purple has the multi-grades, and they have worked well in my stock car, and they lube really well. With the lower viscosity there is less parasitic power loss through the drive train and things just run smoother.

I appreciate your opinions and look forward to your next input.

Thanks & Semper Fi.

stagedtrip

In that case go with the 3.73s. I went with royal purple when I went to 4.88s. Costs more and smells just as bad but seems to work just fine

jadmt

synthetic for sure. while you are in there I would consider putting in a locker of some sort. Heck you need to get a new carrier for the front any way so why not just use that money towards a tru tac or something similar. Another option is try and find some one who has upgraded to D60's and just swap out the whole axle assemblies. It would be a lot less work then swapping gears and no special tools would be needed like when swapping gears. A good gear installer is a talented individual.

BlikitSchmikit

I run Royal Purple in mine and will continue to do so after I swap out my 3.21's to 4.10's. Too bad nobody is looking for 3.21's with low miles
Glad you're spending your free time on retirement well!

v/r

jadmt

they make great paper weights or door holders. If a guy could sell a set of used 3.21's he should move up to Alaska to sell snow to Eskimos.

14JKU

I have a set of rear 3.73 gears taken out of my 2014 JKU with less than 100 miles on them. PM me if you're interested.