Originally Posted by straightsixjeep

98' xj, 4.0/ax15, 3in lift on 31s. I get a loud humming rattle sound on the hwy, comes on around 55mph and is gone by 60mph. The harder Im accelerating the louder it is. It does not make the noise slowing down, only under load while increasing speed. I replaced the rear driveshaft u-joints, the front axle u-joints, the front wheel hubs, both engine mounts, trans mount, and it has a fresh alignment. I removed the front driveshaft to put new u-joints in it, with the driveshaft removed I took the jeep on the highway and the noise is if anything, worse. If Im trying to accelerate rather quickly, the noise gets very loud and I can just about feel the vibration in the cabin. It honestly sounds like its coming from the front end but can you think of anything that would cause this noise? If I get no suggestions my next step is to try a tc drop to see if its actually the rear driveshaft, if so Il look into an sye. However, If I recall correctly it made this noise before the lift.

Originally Posted by sycoglitch

Take a pic of your front pumpkin and rear and tc as level as you can and post. Chances are yes something is binding as you drive and as you accelerate the force is pulling up the front of the jeep and it may be the front dS.

Originally Posted by straightsixjeep

I will crawl under and snap pictures tomorrow. Remember it still made the noise with the front driveshaft removed. Did you have any driveline vibes after installing your 3in lift?

Originally Posted by the John man

hello all,
I would like to know how big of an alternator i can go with out modifications on my 89 jeep cherokee soon i will be running 2 batteries and a 10k winch. thanks

Originally Posted by sycoglitch

Oh yeA. Bad ones. TC drop helped some. Didt know it made noise with from dS removed. Chances are you need a TC drop. I'm in the market for an SYE when I get the money

Originally Posted by straightsixjeep

Ok thanks bud, Il get those pics up and try to get some 1x1" tube or some washers to try and get that tc lower to see if it helps. I appreciate the help.

Originally Posted by sycoglitch

Question. I looked into locking the tranny into 1st. I read a write up on it. Do I need to take power to the switch or can I just put a switch between d 16 and one between c 15 and turn one off when I in that gear. Or keep them on to work normal. Thanks

Originally Posted by sycoglitch

Anyone. Can this damage my 01, or just cause a CEL. I want to cut the wires at the plug D16 and C15 and drop a switch in the middle of the wire and keep it on for normal driving or turn off switch to lock in gear

Originally Posted by NewKindOfClown

I think it'd only be a CEL. Tranny just stays in first, and it shouldn't effect anything mechanically. That's just a guess based on my understanding, though. Somebody should have a more definitive answer.

Originally Posted by NewJerseyXJ609

Does anyone know what temp the aux fan should come on at?

And it should be coming on when the ac is on? I tested my relay and fan. Both test Ok. Also sent power from the pdc to the fan and it came on.. Yet with the real hooked up and ac on it never engages

Trying to chase down my aux fan problems.

Originally Posted by salad

From der 2000 FSM:

Electric cooling fan 4.0L:

With or without A/C request the electric fan will come on only when the coolant temperature is at least 106° C (223° F), and will remain on until the coolant temperature drops to 103° C (217° F) or below. Regardless of coolant temperature, When air conditioning system pressures reach 2068.5 6138 kPa (300620 psi) the electric fan will engage and continue to run until the A/C system pressure drops to 1620.3 kPa (235 psi) minimum, then the electric fan will shut off.

Originally Posted by sycoglitch

This is what I'm guessing too. On 96 and earlie I hear its as easy as a switch install but can't find nothing for 97+

Originally Posted by hick92

How fast you plan to do in 1st