Dando

Well I decided to try locktighting the bolts, we will see if that helps.

Ok so finally I tracked this issue down to the upper aw4 to 4.0 bolts being loose. I tightened them up this afternoon and took it for a test drive. Everything seemed right again the vibration was completely gone. After a few more blocks the vibration started to come back. When I got home the bolts were loose again and backed out a few threads. What can I do to stop this?

Ok so I changed my fuel injectors last night for an extra set I had thinking maybe this would have an effect on the truck. Made no difference. I checked my fuel pressure and it is low, would that cause this issue?

I thought that too, but when checked they seem fine and tight

So on my 90 mj with 4.0 aw4 I am having vibration problems that I am pretty sure are coming from the engine. It makes the vibration in neutral park drive reverse etc. so I doubt it's the driveline. I have replaced the motor mounts and trans mount. After changing those it's somewhat better but now it is pronounced between 1750-2500rpm then it goes away below and above that range. What can I start looking at? Need to figure this out its my daily driver

I have seen a few scattered pics of this being done. I would like to be able to remove the bed from here on out without having to drop the fuel tank.i guess I'm just looking for different photos/examples to get a better idea of what to prepare myself for when it comes to building some supports across the frame to support the tank that won't interfere with the bed when installed.

So I had a bad noise coming from my truck late last night, this morning I crawled underneath and took a look. Somehow the two uppermost bell housing bolts have disappered, I replaced them this morning already. In the process the extra vibration/twisting looks to have caused my inspection cover to become bent and cracked, it was being hit by the torque converter bolts. I removed the cover and now everything seems good. What I am wondering is will it be ok to drive like this for about two days until I can get to the junkyard to get a replacement?

Using holes in the frame rails? That's what I do during my weekly truck wash, you would be amazed at how much crap will come out of those frame holes weekly

I have a 90MJ and I swapped the axle and brakes etc from my 95xj and it had abs in the XJ and not in the MJ. I have noticed no problems from running abs calipers on a vehicle without abs. I think your problem is something else, I'm just not sure where to tell you to look.

In case there was any interest in this problem, I found my solution. The solution was simply replacing the missing bellhousing bolts. Simple fix.

Clogged fuel filter?

For the past few days now my truck has been running pretty normal and good, except when put into reverse. When put into reverse the truck stutters AND stumbles and acts like the engine is surging for fuel. Runs absolutely fine in drive all the way from idle to highway speeds. Trans is full of fluid that looks perfectly fine. Any thoughts? 1990 MJ 4.0 with the aw4 and np231 out of a 95 XJ.

Before replacing my engine in the fall I was having an issue with pretty low oil pressure, I tried changing over to a slightly heavier oil with acceptable success. 15w40 got me by for about a month while I prepared for the swap, not sure on the long term viability of this but I wasn't concerned with that myself, just trying to buy some extra time.

On the ones I'm currently putting together while I wait for spring to come the fitting size on the trans is 14mm x 1.5 going to -6AN hose adding an oring between the new fitting and the trans. The fittings I think you are talking about are generically called AN Fittings, made by many different manufacturers. Not sure on the fittings sizes on the radiator and stock cooler though as it hasn't been warm enough to investigate it yet.

I highly recommend this, it was incredibly easy to do. Stock radio with the ability to plug in an audio device and listen to whatever I want to, plus when not in use my audio cord is completely out of sight and tucked away in the ashtray.

My 1990 does not have obd1

I live up in the rust belt of ohio, don't know about your location but up here I would avoid undercoating. There was a healthy coat of undercoating on my last XJ. I really thought the undercarriage looked good until I deciding to test it one day and found that although the undercoat appeared to be in good shape salt and moisture must have got underneath it and rotted out the entire floor. I believe that the salt and moisture creeps underneath unnoticeable cracks and gouges in the undercoat and becomes a trapped breeding ground for rust. I think this is a major problem here especially due to their new implementation of salt brine. This occurred even though I was washing the truck and undercarriage weekly. If you live in a salt area I would avoid undercoating as it hides your view of the actual metal. I would suggest a coating of por15 and then a chassis coat of your preference, if you really want to coat the undercarriage in something to avoid further corrosion I recommend Fluid Film. It doesn't harden up like undercoating and it does wash off over time, but I have only applied it once this winter to the MJ and when I put the MJ up in the air and look at the underneath it still looks beautiful and you can watch the water and salt bead right off the surface. If you don't live in an area prone to accelerated rusting I would think some por 15 and a quality too coat would be enough.

Having done both, I would definetely say swapping the whole axle would be easier for me than doing a gear swap.

Thanks, I'm going to go out a try turning on ignition and lights to test for sentinel. Now if I have this feature and I don't want it to be active I can just unplug the relay (once I locate it) and this will make the lights work as if the feature didn't exist?

So odd problem with my lights. If I have my lights on and shut the truck off as soon as the ignition is off it will no longer matter if I shut the lights off with the switch the headlights only still remain on. If I turn them off before turning off the ignition they are off like you would expect. Sometimes the rear tailights do this too, the rear is very intermittent but the headlights do this everytime I try. What is going on here? Luckily I put LEDs in the rear of my truck because I didn't notice it that it did this last night and I am sooo proud of the truck for having lights on all night and still starting at -4*F this am.

Reeaaalllly? That could be good news for me... hmmm.... Can you post a pic for me? 95xj booster and cylinder in my 90mj :

I used the master cylinder from my 95 XJ that had ABS, I just didn't transfer over any of the abs parts and everything works great.

Here is a thread where I essentially asked the same question. I still haven't tried any if them yet though. http://comancheclub.com/topic/44543-making-a-standard-leaf-pack-into-a-metric-ton/