flint54

4.56 is lower gear than 4.10, resulting in higher engine RPMs and your fuel use will most likely go up. Top gear on your AW4 is 0.75. 31 inch tires at 70 mph with 4.10 should give 2334 rpm and the 4.56 gear you propose should give 2596 rpm. For 33 inch tires it's 2192 rpm using 4.10 and 2438 rpm using 4.56, if I've pushed all the buttons correctly.

Sorry, I forgot the specs: 4.0 HO, AX-15, NP231 (242 coming) Yes, I know it-can-be shortened, but this shaft spent the first 16 years of life in the chloride-infested MA region and is heavily pitted. Doesn't make sense to keep it now that I have the "opportunity" to do something else. I'm looking for either, the correct original shaft in great shape, or recommendations on which aftermarket shaft to pursue (on limited budget).

Just got the Chr 8.25 bolted in, and noticed the front yoke is tight against the T-case seal. Not good. Read the 5 page thread on D shaft lengths which confirmed that my axle assy is 1" longer than the old D35. The chance of finding the right shaft in the JY is probably very close to zero. My old shaft is pretty pitted, so shortening doesn't make much sense. Any recommendations? Am I going to have this issue again when I swap out the 231 for a 242?

That's pretty much what I concluded after pulling them out. New seals are in, just like we've always done, and all is well. I polished the axle shaft where they will rub since the seal lips are slightly farther outboard than they were on the old seals.

Oh boy do I share your disappointment! That stud plate is welded to the frame. Did it break where the threads end or where the stud ends at the plate? What I suggest is to cut and/or grind off the remainder flush to the plate. Go to the JY and cut off another shock stud from an XJ and have it welded to the plate where the old one was. FSM calls for 44 ftlb of torque for that nut.

Yes, the Vanco is a great option, except they charge $750, plus $200 core charge. Plus, the knuckles I would send them they would probably reject due to rust. I figure I can score nearly all the necessary hardware at the JY for around $250 or so.

Yes, but not very much. Interestingly enough, I took the old ones out and they're the same on both sides----there is no flat side. Plus they have an outer flange that controls the insertion depth. On top of that they were installed wet with RTV and bonded in place. Parts house swears the ones I bought are correct, and the diameter and thickness is correct, but they're very different than what I removed.

If it spits, you are at least building fuel pressure in the rail. Would be good to know how much pressure, but that's probably not your issue.

The strap bolts are unique. They're a J-bolt that hooks into the frame. If you old ones had to be cut you'll need new ones, and they're NLA at dealer. I was very lucky and found a good pair at the JY. Hope yours are still good.

The two holes on top of the tank are vent lines, but they have a rollover valve installed that prevents loss of fuel when you're upside down. The grommets that hold those valves deteriorate with age. If you're really careful, and have lived an honorable life, you just might be able to salvage your old ones but don't count on it. They are still available from the dealer, they cost about $10 each, and will likely have to be ordered. If you're not certain the old ones are good, I suggest just replacing them. It sure beats pulling the tank again!

Have you checked for fuel pressure at the rail?

I'm replacing axle seals. What I found looks opposite than the way I've always installed them (flat side out). The FSM doesn't show orientation of seal. In the image, you can see the old seal, and both sides of new seals. So my question is, which is right? Is the old seal I'm replacing correct or incorrect, or does it even matter? I've always installed them flat side out. Image Not Found

Now that I'm nearing done on the rear disc brake conversion, I'm headed up front next. Since I'm going to be changing out axles anyways (3.07 to 3.55) I see an opportunity to upgrade the brakes. I've read the other forum posts on using the TJ hubs and WJ knuckles/calipers. It seems do-able, but all write-ups caution that the calipers will not clear 15" wheels without shaving. I'm not going to change wheels, I just had mine refinished and like them too much. My questions are: 1) concerns about shaving calipers (assuming they don't leak)? and 2) have any of you done this mod on your MJ? Thanks!

Pete, I know I probably shouldn't worry about it, but my symmetrical mind is struggling. :D The tank is at about 1/2 full, so I figure about 57lbs of fuel (18.5/2*6.2), and the spring rate of new MT2200 is 130lb/in, so the fuel should account for 7/16" delta. I feel much better now - thanks!! :D

Hmmm. I puzzled how the front springs would affect a frame to ground height difference measured at the leaf spring rear attach point? The front is level side to side. I may still be changing the front springs soon, but that will come with the front axle assembly replacement (one end at a time). After the 3.55, Chrysler 8.25, locker, MT2200 spring, disc brake, rear mod is done (another week or so) I'll tackle the front. I'll look into the OME coils, as I'm a bit leery of adding any more spacers beyond the one already in place.

Since owning this truck, I've always noticed the LH rear is lower than the RH rear, and I've always attributed this to a sagged spring on the heavy side (fuel tank and driver). Now that I've installed new HellCreek Metric Ton springs, the difference remains the same. I'm measuring fixed frame point on each side, to the ground. The LH side is 3/4" lower then the RH side - still. I know with certainty this truck has never been damaged, and has never seen anything more challenging than the occasional speed bump or pot hole. Why, I wonder, is this so far out from spec?? FSM body point diagram indicates less than 1/8" maximum deviation LH to RH. Any ideas?

RTV must be more abundant in your area. Permatex RTV around here is more like 5 bucks, then factoring in the time to scrape and solvent wipe both sides, not to mention what I inevitably get on myself, if this gasket lasts a few rounds it seems I'm ahead of the game.

Anyone ever try one of these? http://lubelocker.com/products/products/view/5/12 Seems a bit pricey at $20, but reuseable and no more RTV.

I recently put a pair of SpiderTrax spacers on the back of my 92 and I'm very pleased with the fit and the quality. Use Locktite.

The six foot bed uses the 18 gallon tank. I suppose fitting the larger (23.5 G) tank is possible, but I believe it uses different strap attachment points and your frame isn't configured that way. Tank has metal necks, to which the filler (and vent) hoses are attached with hose clamps. A leak there would not explain losing a quarter tank, UNLESS the gas was being lost as the tank was being filled rather than later. The hoses and the filler tube that attached to the body are easily removed and replaced, but be extremely careful to use only tools that cannot make sparks. I agree with whoever said that if there's any doubt at all about the health of the tank, just replace it. And, at the risk of being overbearing, please be cautious. I set a vehicle on fire once due to a very minor fuel mistake, and it was an old German car I was quite fond of. Given your observations so far, I would evaluate the neck hoses and fitting at the body before removing the tank. They have to be unfastened anyway. You just might get really lucky and find a bad hose.

Regarding the tank, you might find the problem to be the sending unit installation seal. If so, that would be an easy and low cost fix. Otherwise, a tank R&R isn't too tough to do (I did that job last month), but you may find the hanger strap bolts so badly rusted they have to be cut/replaced. Does the tank have any obvious damages or rust spots? There are many sources for new tanks. If you buy new, I suggest coating it externally with something durable like POR-15 to prolong life. Demating the back end of the drive shaft will make the tank job easier. Mark it first. Regarding the springs, anything less than replacement still leaves you with old, tired springs. Less than $200 for new springs (suggest HellCreek suspensions) and a couple inches of lift isn't radical. But, lift does put you on the slippery "modification" slope, and before you know it you'll be spending every spare dollar and hour on your truck. Your family and your employer will abandon you, and you'll have truck fun "happily evermore". While you're underneath, scrutinize every inch of floor pan surface for the inevitable corrosion, and grease all your fittings. As Dechion said, the cab lights are most likely made functional again by abrading the contacts, but be very careful removing them as the securing tabs are weak and easily broken. PB Blaster will become one of your best friends. And WELCOME to the MJ world! :clapping:

Steering back to topic, it turns out the ZJ backing plates (yes, I mean the caliper brackets, not the sheet metal) needed only a very minor ID polish to remove maybe 0.010" at most and they now slide on snugly. Also turns out the Aussie for my axle is temporarily unavailable (AU flooding), so it looks like the Powertrax no-slip will be the unit I use to replace my open diff. Got the perches ordered today (Morris 4x4 in FL at $23 for the pair delivered) and tomorrow I start grinding off the old stuff. I located today some good info on driveline angles and how to measure, at this website: http://www.vibratesoftware.com/html_hel ... Angles.htm Towards the bottom of the page is a "specifications" section I found most helpful in figuring out the right relationship between transfer case yoke angle, driveshaft angle, and axle pinion yoke angle. Will use this info to establish the correct spring perch position. Anyone have opinions on the Powertrax product?

Recap: Dumping Dana 35 3.07 for stronger 3.55 Ok, I have the Chrysler 8.25 axle assembly from a 2000 XJ. I've also bagged a set of calipers and backing plates from a 97 ZJ to add disc brakes. The backing plates will require enlarging the center hole due to axle tube size difference. Both the XJ and the ZJ backing plates required quite a bit of force to remove (press fit or rust fit, perhaps a bit of both?), and I'm wondering just how tight this fit needs to be. The braking force is rotational, and I believe it transfers to the axle tube through the bolts. Does anyone think the center hole need to be "press fit" tight? Or just slip fit? Next question, does anyone here advise against the Aussie locker?

I like Tire Rack's website with the capability to compare both specifications and user preferences and shows "miles driven" data as well. I chose Firestone Destination AT's, 235/75-15. Available in 31" at $129 and rate higher than the DuraTrac in every category other than snow traction.

I put 1.25" hub-centric spacers (SpiderTrax) on the rear a month ago, and, other than better appearance, I notice no difference, having driven nearly 2000 miles since then.