Those of you with 4.88's in your D30?

I have a few questions for those of you who have 4.88 gears in your D30. I am considering going with them but am just a bit concerned with the strength of the ring an pinion when going that low. I have heard that they are weaker then running 4.56's but have also heard that they have held up fine. I would like to hear from those of you who have them.

- How have they held up?
- How hard do you wheel with them?
- What size tires are you running with them?
- Are you happy with the way they drive and wheel?

- How have they held up?

I broke one set the first time I went out, but that was because I jumped my XJ off a sand dune and landed on the front axle. Even then I believe the ring and pinion broke because the housing flexed, not because of the strength of the ring and pinion. Since then I have replaced that housing and installed a crane diff cover and have had no further problems.

- How hard do you wheel with them?

Hard, people tell me there is more then one peddle down there, but that other ones no fun so I don't make a habit of using it all that often, and I’ve never taken a by-pass with out at least trying the hard line first.

- What size tires are you running with them?

33" TSL

- Are you happy with the way they drive and wheel?

Extremely, I worry more about my U-joints then my ring and pinion. I think the HP design of the XJ D30 makes the R&P significantly stronger then the R&P in a TJ.

The key seems to be a stiff aftermarket cover to stiffen up the diff and avoid the flex that seems to spit teeth out.


I've talked to a few people that say 4.88"s aren't an issue with a reasonable skinny pedal and a stiff cover.

Thanks for the replies everyone! I think I am going to go with them and just wont get too wild with the skinny pedal lol!

A fellow Bako guy, Nice!
I have had my 488's in for about 5 years. Zero Problems. I have went anywhere that I have wanted to. I have 33's and the Disco Housing and stock cover and fresh 4.0.

My Father N Law has 35's, non Disco, stock cover, and a stroker! He has had his in for about 1 year and broke about 3 teeth off while in reverse.

I would say do it. I love mine (untill they break, then I'll piss n moan about it.)

I wheeled a D30 with 4.88's and ran 36" sx's locked, I broke a Ujoint and a main leaf in one (on my yj ) run but the R&P are still doing good.

I wheel 33" tires on my D30 with 4.88's (obviously no, it's not a DD). I don't wheel serisous rocks often (mostly forrest trails and sand/mud) but when I do, I've been known to substitute skinny-pedal for my lack of a rear locker. (it's something I'm trying to fix; but I'll just be honest here... it happens)

I've been OK so far, but I do remember when I was installing the axel that I was looking at the pinion of a D30 4.88 thinking how small it looked... Kinda like what you'd expect to find on one of those BarBie-Jeeps that 3 year-olds cruise around the yard in...

I do have the WARN dif skid that probably adds a good bit of stiffness to the whole thing. And, like I said, I don't hit it hard very often.. but I have given it a few good shots, and it's got me home every time... So far.


- Not that I'll be supprised if it blows to bitty bits... but as I mentioned, it's not my daily driver, so I'll still be able to get to work Monday morning. they ARE fun though.


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