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gears

the work itself isn't all that hard its just time consuming, precise, and requires a lot of patience, plus the tools themselves will cost as much as the labor to get them installed..

I would have a QUALIFIED shop do them, if you mess them up or just don't get them perfect you WILL have noisy gears and run the possibility of them jamming and locking up (worst case). If they end up being noisy you have to start all over again, if a pattern is worn into them though you most likely will never get them right again so you will need new gears. Set up gears are also something you should have as well as a press, if you have the guts then try it yourself but I sure as hell would be pissed if my pinion gear collided with the ring gear wrong at 60 mph locking up an axle and causing an accident, my xj is a DD though.
I think you might not know what you are talking about, at all, from this statement. They won't lock up, but they will overheat and probably wear badly and you'll need new gears.

Sure off the line with 4.88s and 33s was nice.

Cruising on the highway wasn't the greatest.

I tend to do anywhere from 70-80 on the highway regularly (as in everyday).

At 70 mph I was approaching 2700 rpm.

Maybe some people do 60 mph all the time and that's fine, but I don't.

It always just felt like I was spinning it too much. Not that it ever did any damage.
I run mine at like 3k all the time... 3.55s/ax15/33s kinda sucks.
 
I plan 4.88's with 33s on my 4 banger... I dont see them being very nice on 31's. Had 4.88's in my old yota with 31's and the thing would spin in 1st AND 2nd gear... with a 4 banger. Also hit about 3000 rpms at 70, which is what speed a good 90% of my driving is done at, wasnt awfully fun.. I could only imagine a 4.0 behind that setup..
 
4.88 seems like a good gearing for 35's that do a lot of road/highway as well right? thats what i have been led to believe
(btw thanks for all this input, very helpful)
 
yup... be careful and make sure the setup is perfect though if you're putting 4.88s in a 30. a 30 on 35s = ticking time bomb if you get on the throttle and don't have it built to the hilt.

(yes... I just opened that can of worms.)
 
yup... be careful and make sure the setup is perfect though if you're putting 4.88s in a 30. a 30 on 35s = ticking time bomb if you get on the throttle and don't have it built to the hilt.

(yes... I just opened that can of worms.)

what would u do to try and avoid it from "exploding"? i thought 35 was the max safe tire size.. on a d30
 
yup... be careful and make sure the setup is perfect though if you're putting 4.88s in a 30. a 30 on 35s = ticking time bomb if you get on the throttle and don't have it built to the hilt.

(yes... I just opened that can of worms.)

Its not the gear ratio its the 30 itself I've personally seen 3.73's blow up on 33's and just about any other d30 ratio with breakage
 
Its not the gear ratio its the 30 itself I've personally seen 3.73's blow up on 33's and just about any other d30 ratio with breakage

I've seen my fair share of OEM (open style) carriers split in half...blown up spiders...blown joints from spit out c-clips/stretched ears...tubes spun in housing...
 
Its not the gear ratio its the 30 itself I've personally seen 3.73's blow up on 33's and just about any other d30 ratio with breakage
I've never blown up a gearset (yet) but I'm getting pretty good at blowing up ujoints/yoke ears with crummy ATs and a locker.

It's a good thing I am running a very common factory ratio in it and consider it a wear item. $100 and a few hours gets me a new one from the junkyard if I blow something up inside the diff.

I know guys out west can make a polished 30 live on 35s but out there, they keep the rocks and mud separate. Here in the northeast rocks and mud are mixed together like shepherds pie and you're gonna do a little slipping and bouncing everywhere... good luck with that 30 on 35s.

Not locking it will make it live for a lot longer. I beat the absolute shit out of my 30 on the same crummy ATs for an entire year without ever breaking it, and I was running factory axleshafts with plenty of rust and the original 297 ujoints. But I also slid all over the place and had to be a lot more throttle happy without the locker, I can easily crawl things now that were full-throttle rev limiter assaults before.

If you want a reliable frontend for 35s that you can safely put a locker in, build a 44.
 
does a front 44 or 60 just bolt in? (00'xj)
A Wrangler Rubicon front 44 will. But it is hardly an upgrade. Only benefit is the larger ring gear and factory locker. Or a Rock jock series and G2 series.

I personally ran 4.88's on 33's and liked it. I don't crank down the highway, 70mph tops, and sat right around 26-2700RPM. Less down shifts on road, good torque and good crawling off road. I would absolutely do it again. I'm going to be running 4.88s with 35s now, but only because I am limited to that ratio with my rear axle.

I'm doing a Ford HP 44 swap right now for 35s and it's not terribly difficult, just costly and time consuming. For almost the same money you can buy a G2 housing geared, locked, and ready to bolt your factory outers on and slap underneath.
 
A Wrangler Rubicon front 44 will. But it is hardly an upgrade. Only benefit is the larger ring gear and factory locker. Or a Rock jock series and G2 series.

I personally ran 4.88's on 33's and liked it. I don't crank down the highway, 70mph tops, and sat right around 26-2700RPM. Less down shifts on road, good torque and good crawling off road. I would absolutely do it again. I'm going to be running 4.88s with 35s now, but only because I am limited to that ratio with my rear axle.

I'm doing a Ford HP 44 swap right now for 35s and it's not terribly difficult, just costly and time consuming. For almost the same money you can buy a G2 housing geared, locked, and ready to bolt your factory outers on and slap underneath.
they are also low pinion, use thin factory style mounts, stock brakes, and stock sized balljoints, and same unit bearings
 
they are also low pinion, use thin factory style mounts, stock brakes, and stock sized balljoints, and same unit bearings
Right, they're basically a Rubi 44.But depending on your wheeling style they're fine. I would suggest boxing/gusseting the UCA mount on the passenger side and beefier LCA mounts. Still better than a 30 for 35s in my opinion.

is this the D44? or the HP44?
The G2 and Rubi axles use thin mounts and factory brakes. They're not *great* but not terrible either.
 
I agree...I would run a Rubi D44 over a D30 if I could get one at a reasonable price.

They still need alloy shafts, full circle clips, and mini skids to beef up the LCA mounts...but you get more R&P beef, a bigger/stronger carrier, 30 spline inner shafts.
 
Same... if I was richer than Midas I'd consider a G2/Rubi 44 with RCVs.
 
I think the biggest reason DIY gears fail is the installer was impatient and thought it was "good enough". It takes alot of patience to get it done right. Having the right tools is a huge factor because it takes much longer without the right tools. Also, without the right tools you have a good chance of damaging the bearings removing them. It is best to at least have guidance from an experienced installer.
 
I've been setting up diffs for years, i will tell you from experience, its an art! You can have the tools and even the know-how but you have to have the feel for it and can read a good/bad pattern.

As for 4.88's and 35's, I wish I could stuff 5.38's into the 8.25. 4.88 is good but not great.

This is what I'm taching on the highway with 4.88's/35's and a corrected speedo. I would be looking at 2600 rpm with 5.38's but I would just slow down to keep the old 4.0 in the sweet spot.

P1020426.jpg
 
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