Hi all, not sure if this is correct sub for this. So if not, please redirect me.

Specs on xj:
95 sport
4.0 & auto
HP30 - 3.55
C8.25 - 3.55
32x11.5 mud terrains

Plan going up in tire size to 35s

SO I am in a bit of a pickle with a re-gear, currently my gears are stock 3.55. I have recently acquired a ford 8.8 w/ 4.10s. That 8.8 is currently locked and ready to go.

I thought at first I wanted to redo the front HP30 with 4.10's ( not locking front at this time). Have done a good bit of reading and it seems the general consensus is, its not worth buying and re-gearing a HP30 to 4.10, its more worthwhile to find one in the junk yard (which I haven't found yet).

Then after researching more & knowing that I want to up tire size to at least 35s, I thought perhaps 4.56 gears would be the way to go. Luckily I have a buddy that knows of a guy looking to sell his HP30 w/ 4.56 for a decent price. So theres that..

So, is it more worth while to swap / re-gear my HP30 & 8.8 to 4.56, OR just re-gear HP30 to 4.10

 

4.10's isn't enough gear for 33-35" tires. I personally run 4.56's with 35's and love the combination. I would ditch the d30 if I was going bigger than 4.56's or 35" tires.

If you are definitely going to do 35's, go with 4.56's. You won't notice a huge difference from 3.55 to 4.10 and your Jeep wouldn't be too happy either.

 

what he said x2

 

What would you recommend to pair with the 8.8 for 35+? I was under the impression of there only really being a D44 OR 3/4 - wontons ...

 

I would just throw a D44 for the front if going bigger. The HP D30 is a stout and underrated axle. It can handle 35's when built up a little (chromo shafts). The problem is the pinion is very small once gearing more than 4.56. Even 4.56 its pretty small but that's where I draw the line. Mine's locked and I've wheeled it pretty hard through Rausch and haven't had a problem with it. I also can control my right foot and know that the little D30 will throw the nuke lever if you start to bounce. I think the reason people say D30's suck is because they can't drive but what do I know.

 

Is it homemade? I wouldn't touch it without a valid receipt specifying exactly what was done from a reputable shop. Too many neckbeards toast a gear set from an adjustable wrench/screwdriver/backwoods install and then try to get out from under the axle on CL.

 

Definitely good advice here. I've bought "great" axles from friends and still been burned. You know how it goes... they have exactly what you need... 4.56 geared dana 30 with a locker ready to go, right? Can't help but think to yourself allllll the money you're going to save. Then you tear it apart to make sure it's solid just to find out the axle shafts are twisted to near breakage, the locker is completely wore out and broken, the bearings are wiped, and for the grand finale? The carrier is cracked in two places. Don't let this happen to you lol.

 

4.56 is what i'd run. i ran 4.10s on 35s for years and while it was ok, i wished i had deeper gearing. I had a built D30 (truss, locker, chromo shafts). I could keep it intact with the proper throttle input, but the unit bearings and ball joints were wearing out too often. now im running a built 44.

 

Whats the percentage of off road time? If its a DD or only moderate wheeling 4.56's would be good. If lots of trail time or harder wheeling maybe consider 4.88's? It would be a LOT of gear for the pavement though..

 

I put 4.10's in mine with 32 x11.50's and wish I would have gone to 4.56. We are going to do by buddies new build this weekend and we are putting 4.56 in it.

 

the pinion gets really small on a D30 with 4.88s. i'd never run that.

i run 5.13s and 35s on pavement. yeah the motor winds up pretty good but its really not that bad and quite nice to have the low end torque.

 

Good call, a 44's pinion would be good to go right?

 

I am now running 2 sets of tires/wheels 33's on steel wheels and 35's on beadlocks. I had 33's when I re-geared to 4.56 was perfect then picked up the 35's and still the 4.56 works fine for me but with both. A do over would be a 5.13 gear as I drive not much on the road and trailer it most of the time (just in case of a problem).


I have the D30/Chy 8.25 29 spline both with stock axle's and have not broken anything yet but do carry spares. If the D30 does ever start giving me problems I will truss it, new axles and beef the thing up. I pick my lines and easy on the skinny peddle could help me also I don't beat it to death.

 

Thank you all for input

It's on the road more in the winter months, summer months it drives to the offroad...

I am now quite weary of buyin a possible home built axle, and really hadnt thought about all the possibilities of broken internals

 

Good call, my personal suggestion would have been 4.88s for 35s, but then again I wasn't thinking about how small the pinion was getting at that ratio on the D30. I personally wouldn't run anything taller (numerically lower) then 4.56s though. For where I play and in my experience there, 4.56 is about a perfect fit for 33s, and is "good enough" for 35s.