I tried searching but really didn't find anything specific. So...

I have a 1999 5-speed stocker with ~340,000 KM on it. I'm going to be going 31s. I found a few months ago another 29-spline C 8.25 with 3.55:1, recently rebuilt with half the mileage on it, for $100. For an extra $30 the guy threw in an e-fan, coil spring isolators, a rim, and 3.55:1 R&P and carrier from his D30. All from a 1998 automatic - the guy swapped for a D44 and regeared up front.

My HP D30 presently has 3.07:1 stock gears. Will I need to re-shim when installing 3.55:1 stock gears? Are they the same depths and thicknesses? I will be installing new bearings.

 

carrier shims? i would say you never know until you get it r&r'd and actually get a pattern. you may get lucky though.

 

Yeah carrier and pinion shims. I expect to have to set preload and get new fasteners (which I suppose would be the same if you were just disassembling it and reassembling for fun). I read through this excellent writeup: http://www.pirate4x4.com/articles/te...sta/Gear_Setup It sounds manageable but I'm wondering if I really need to go through the expense and effort for what is really a factory gear swap.

 

You'll need to set up the gears. All the shims will probably need to be changed. I have gotten lucky on the shims on the pinion before, and they be the same going from one ratio to another, but I've always had to change all the shims on the carrier, which is a pain on a Dana axle unless you have setup bearings.

The far easier option is to just swap in a front axle out of a 4.0 auto XJ that will have the 3.55's already. That's what I'd do, since D30s with 3.55's are so common, and a D30 is only worth about $100 tops. A master install kit to put the gears in will probably cost at least that.

 

Ah, drat. Is this due to wear that it all needs to be changed?

Maybe in your neck of the woods lol. Here TJ owners eat HP D30s like candy. They are few and far between... don't think I've seen a parts XJ in a year that didn't already have the front axle spoken for

 

Not really due to wear, but with your current shims there is a good chance the pattern wont come out right. You may get lucky, you never know. But any time I regear something, I buy a master install kit, comes with new bearings for the carrier and pinion, and plenty of shims in different thicknesses to get it set up perfect. I have reused shims, but never have got lucky enough that carrier shims went back in exactly how they came out. I've always had to add and remove carrier shims to get it right, and its just easier if you have plenty of shims to work with.

And yeah, if you cant find a good HP30 in your area, swapping axles may not be best for you. Guess I'm lucky, there are HP30 axles everywhere around here, for $75-100 in good shape. Pull a Part is a little overpriced, but every XJ in my local yard still has both axles under them too, all HP30's, and a few 8.25 rears.

 

Okay, maybe I'll shell out for that anyway. I couldn't tell from RockAuto's site, but do most of 'em include seals as well? Both lower ball joints are EXTREMELY well lubricated lol.

I already have the gears, if I can find a dial indicator for cheap or rent one I'd rather know that the bearings are fresh vs. waiting for another D30 to magically appear at a reasonable price.

Of the two XJs in the JY here, one of them is vac disco and the other has been sitting in mud/water for a year or so. Most of the Jeeps locally are ZJs with CV D30s

 

I just pulled a 99 HP D30 with 3:55s in them for the swap into my 2000 with a LP D30.
I have an 87 HP D30 with 4:11s in it I'm going to swap into the 99 housing. Too bad Kingston is on the wrong side of Toronto because I'd just swap you the 3:07 axle. The 87 axle housing is too rusted for my liking or I'd just use it.