New Guy, 96 ZJ
 

New here. Few questions

Bought a 96 ZJ yesterday, I'll post photos later it was dark by the time I picked it up yesterday.

Seems to be in great condition overall but I've posted before (I think in the wrong forum, sorry) about a slight transmission slip into 2nd gear. I don't think it's anything to be too worried about but I'd still like to drop the pan and change the filter. Is this as straight forward as it sounds? Any tricks or secrets I should be aware of before I do it? I plan on picking up a WIX filter from RockAuto. And adding some type of no-slip when I refill the fluid.

I won't be driving it for a few weeks as I'm waiting for tires to get shipped in from tirerack (it had been sitting for a while as it wasn't the sellers daily driver and the rear tires had some pretty decent dry rot).

Also while driving it home last night when stopped at a light the whole thing seemed to almost do a "shutter" for lack of better term. Could this be another symptom of the transmission? Guy here at work said it could be a vacuum leak causing it? Only seemed to do it while at idle and not moving, or at least that's the only time I would notice it. Was about a 20 min in town drive to get it from point A to B. Hopefully I'll be able to take a better look at everything today if I don't run out of daylight.

Welcome to CF! What engine and transfer case do you have?

PLEASE, don't put any additives in the trans. You'll only be asking for further problems. The filter change is easy. You only get 4 qts of old fluid out of the pan and the trans holds about 9 qts. Do a fluid change again after a while. I bought a premium reusable gasket from the dealer. Pricey, but good. Use only ATF+4 fluid. Check the fluid level in NEUTRAL, not park as instructed on the stick. You'll probably need between 4.5 or 5 qts on the refill because of internal drainage.

The shutter is probably a dirty IAC (idle air control) and can be easily cleaned or replaced depending on condition and wear. On the 4.0 I6, it just mounts on the throttle body with 2 Torx screws. Be sure not to lose the seal when removing it. I'm a firm believer in using only Mopar parts for sensors because of quality issues with aftermarket suppliers.

I would drain and inspect both differentials and change the transfer case fluid also. Check over all your vacuum lines, suspension bushings, tierod ends, and driveshaft universals when you do your initial inspection. If it's been sitting outdoors for a while, check the wiring for critter damage, as in bite marks in the insulation. IDK where you live, but porcupines LOVE the salt on brake hoses!

4.0 engine, not sure of the transfer case or trans, it's a Laredo if that helps. When I checked the trans fluid on test drive before buying it seemed to be slightly low, but not burnt or evidence of debris. I'll check the IAC, that's something I've replaced before (my currently daily driver is a 92 Comanche with a 4.0 so I'm familiar with the 4.0 engines.

Haven't had a chance to really explore under neath the jeep but if it's like the engine it's spotless, previous owner kept it in very good condition. I have access to a garage lift that I'll be using once new tires are on and I can get it there. I'll provide more info once I get a chance to really look at everything. Thanks for the help!

Okay, transfer cases;

NP/NV 249, constant 4wd, shift pattern 4hi, N, 4lo
NP/NV 242, 2wd, 4pt, 4ft, N, 4lo (pt)
NP/NV 231, usually only in the XJs, 2wd, 4hi (pt), N, 4lo (pt)

Most 4.0 ZJ Laredos were 242, but the 249 was optional.

Cool, it’s a 242.

In my opinion, the best and least troublesome one there is. The one thing I like about it is when surprised by windblown snow on the highway, you can shift to 4ft at 60 mph without any worries.

Good to know. I live in eastern VA and we don't get snow too often, but I do travel to north east PA in the winter months and that lake effect snow can get you quick.

I was able to do a little crawling around yesterday and there is transmission fluid leaking from somewhere, hoping it's just the pan gasket as I plan to replace that anyway. Is there any other known areas the fluid could be coming from? An inspection plug or something I'd be able to find easier once it's on a lift? Also saw some oil at the bottom of the oil pan, hoping that is just the filter housing as the previous owner says he's replaced that before. I mentioned dropping the oil pan to my dad and replacing that gasket as well, or is it just RTV? Have you ever done this? He said some engines you have to raise or lower from the mounts to get the clearance to drop the pan. I'll verify the leak location before getting into any of that, ran out of daylight.

The previous owner left me with a bunch of the old sensors he's replaced, the idle air control is one of them, so assuming the one installed is still good, is there a recommended cleaning procedure? Just don't want to ruin an assumingly good sensor using the wrong cleaner.

Thanks again!

Dave is spot on about using Mopar sensors, give your Jeep some love, don't be thrifty when replacing sensors unless you absolutely have to. Nothing worse than having to extract yourself or a loved one from some nasty obscure locale in the middle of the night due to failure of sub quality parts.

I have this "thing" about using RTV on a transmission pan. I've seen cases where little pieces have found their way into the valve body and caused shifting problems. Usually, if everything is clean and flat, you shouldn't need a sealer, but if you do, use an adhesive spray product on the gasket only. Permatex Spray-a-Gasket is what I've used.

My 4.0 is starting to use a lot more oil between changes and an inspection shows either a pan gasket or rear seal leak. My point is if I'm going that far, I should change the rear seal as well. There's 187K on her now.

I've been told to use NAPA Brak-leen on the IAC.