Dzimm

Just the fact they posted it as a 98 MJ is a huge red flag. They either made a typo or have no idea what they have, and judging by the paint, I'd say they don't know what they've got. It could be worth the trip if they only figured out how to operate a spray can and not the toolbox. Can't really tell with the few pictures they offered tho. If you don't mind spending the money to get there and walk away from it, it can't hurt to just look. However, my honest recommendation would be to find something else closer to you.

Thanks for the help Eagle, this will help greatly. I double checked and it is view only so it can't be edited by us.

I run valvoline high mileage 10w30 synthetic blend with Bosch oil filters on all my XJs/MJs. Oil comes out more dark brown than black after about 4k miles.

Thanks. I'll have to try the Google tip.

You bring up a lot of good points. I'm really more in the research stage for what I want to do and to price things out based on what I will accomplish with them, that way i have an idea moving forward what I want to do and need to plan for, and some of those will be subject to change as the build goes on. I can't run it as is due to the height/width thing and I cannot use the "tracks" after events as they are privately owned parking lots. The big thing I'm worried about is breaking the D35 because I need to be able to drive the truck as I have no trailer and when I bought the truck, the diff was very low on fluid so I have no idea what kind of damage was done as I have yet to have time to pull the cover. Do you happen to know the names of the lowered builds? I searched around quite a bit but didn't come across any.

For that tire it comes out to be 2331rpm for 3.73 and 2218.13rpm for 3.55 at 60mph. I do like your math a lot better. The formula I was using does give a close answer as long as I do the conversion to 5th gear. I didn't even think about the trans ratio. Thanks for the help! I think I wanna go with the highest gears I can so I'm gonna probably snag a Ford 8.8 with 3.73.

I can't do an adapter since I am lowering the truck, I will actually lose travel in the driveshaft so the extra length of the adapter would be too much. My driveshaft is also the double walled one that can't be modified so I have to have one built if I go that route. I wonder tho if I could take an XJ shaft and the adapter if it would be long enough.. How long is your adapter from center of u-joint to matting surface of the flange?

Ohhh that makes sense.

Foot in mouth.. I see the problem, my blue truck has 29" tires, the red truck has 27.5" tires. the exact size is p225/70 whatever the p means. I still don't understand how your math works tho. The formula I found is (speed x gear ratio x 336)/tire size = rpm. So by that math with the 27.5" tire, 3.07 gears, at 70mph it comes out to a little over 2600 rpm, which is close to what my gauge says on the highway. So by your numbers, say I went with a 24" tire and 3.73 gears, what would the rpm be at 70mph?

I am nowhere close to getting a spare parts bin setup for it. It won't see the track until next year at the very earliest. As for the post about tire size and backspacing, I posted towards the end that it's basically impossible to get the truck within limits of stock street classes unless I ran on the rims with no tires so I gave up on that. Now I'm setting up the truck how I want and will run in whatever class I end up fitting in because I'm not looking to be competitive as much as for the fun of it... And the fun of smoking the old rice burners from the stoplight. At this point, all I want is a DD that is setup to autocross as well. That's what autocross is about, having fun in whatever vehicle you have no matter if it's bone stock off a dealer lot, or purpose built for racing. I'm looking to be somewhere in between those. IF I end up deciding I want to become competitive and set it up strickly for racing, I would go all out with a racing setup but that's not what I want to do at this point.

My true rpm with 29" tires right now is more like 2250 at 70mph according to the tach. I used some formulas I found online to get my numbers and they seem to be slight over estimates, which is good because lower rpm is better on highway. As for smaller tires, I can go as small as I want to but I figure I have more tire options than I do axles and gears options so if I setup the axles and gears to what I want, I can choose tires later based on what I have. If I had to guess, I would say it will prolly be something like a 24"-26" tire. The truck will see mostly highway driving hence why I want to keep mpg/rpms in mind. It will see the track maybe 4-5 times a year so I'll be using the same tires for DD and track.

The pinion length isn't the issue, the 8.8 has a mounting flange not a yoke like the driveshaft has so the end needs changed. I think 3.55 is what I want to go with but I can't seem to find any 8.8s locally that are lsd and 3.55, they all 3.73. I'm keeping my eyes peeled and asking around tho.

Carpart has some listed but the only ones remotely close to me are $400. Cheapest I saw was $300 but too far away to offset the cost difference. If I use the C8.25 I've got, I can do a brake swap and add the limited slip cheaper than anything else. Just a lot more work.

So I'm trying to figure out what I want to do for a rear end for the autocross truck. I am looking to switch to a stronger rear end, with lower gears for quicker acceleration, limited slip, preferably disk brakes, but still be able to get decent gas mileage on the highway. I will be switching to slightly smaller tires but the size is still up in the air. The truck is a 92 4.0l AX15 2WD with a D35 3.07 gears and runs about 2500rpm at 70mph on 29" tires. I was looking at Ford 8.8 axles because they are strong and limited slip from the factory and seem to all be about $200-$250. However I'm only finding limited slip with 3.73 gears. By my math, that will put me at 3000-3500 rpm at 70mph depending on tire size (smaller tire = higher rpm). I would also have to have a new driveshaft made so all in going with a Ford 8.8 I'm gonna be about $500ish. If I did a C8.25, I could do 3.07 or 3.55 gears and add a posi lock to it. Going this route, I can keep the driveshaft. The axle would be $200 and the limited slip $350 putting this at $550. This however would leave me with drum brakes. I could get a liberty C8.25 for disks but they are about $400 on the cheap side. Now I do have a 95 XJ with a C8.25 with 3.55 gears that I am going to pick parts from for the truck. With 3.55 gears I'd be running about 3000 rpm with 29" tires so I'd end up probably around 3500rpm with smaller tires. If I used this axle, I would only have to buy the posi lock so would cost about $350 all in. I want to get your guys opinions on what to do. What gears/axle should I go with?

What trans is in the XJ? From what I've seen/heard, the bellhousing are different between the 4.0l and 2.5l engines so you'd be better off finding an XJ with the 4.0l Also the gear ratio in that front axle is very unlikely to match what is in the MJ due to the different engines. The front axle from any XJ will bolt right in to an MJ as well as the front driveshaft. If you swap the rear axle (only do this if it's a C8.25 because it's way stronger than a D35) you will have to move the spring perches out slightly.

Nice! I messaged him to see if we could work out a deal. This will be much easier than building one for my truck. May even try my hand at making a mold to reproduce a few of these if I can get ahold of it.

I've got a rear window seal i can part with.

To add a "jumper" switch, run a wire from the secondary battery to a switch, then from the switch to the solenoid signal. Basically do just like the digram but there would be a second signal wire coming from the secondary battery that is switched.

Welcome! You should start be going through cruisers renix tips. This will eliminate most, if not all issues you have or will have right off the bat.

If you can find a super cheap or free Dana 35 from an MJ I'd go that route. If you have to pay for an axle, get a C8.25 from an XJ and just move the perches to the right spot. Most of these will be 3.55 gears. You won't ever break it.

In that case yeah, it doesn't matter. Everything is coming out and coming from the 97+ XJ. You will have to fab all new mounts for the dash but the wiring harness is encorporated into the dash, you'll just plug it in to the other wiring harnesses from the XJ. Check out some of the 97+ build threads to see what everyone has done.

I looked into the 4bt for my blue truck but it would require a lot of frame stiffening. The MJ/XJ isn't designed to handle the torque of a diesel.

No difference I'm aware of, same amount of work. You don't plan on ONLY swapping the dash do you? Swap it ALL or nothing.

I did some reading and it seems that limp mode will not reset if the code/fault is still present. These are the three ways I could find to reset your codes without a scan tool: - unhook the battery for an hour or more - touch your ground wire to the positive terminal of the battery to drain capacitors - turn key on and unhook battery for 5 mins.

Thanks!