Bad Squeaking When Thottled

[99XXXJ]

I Have A Really Bad Squeaking When My 99 Xj 4.0 4wd Is Throttled. It Almost Sounds Like A Bird Chirp That Speeds Up With Acceleration. I Thought It Was The Tranny So I Added Fluid....nothing. Any Suggestions??

[72mino]

From your description it sounds like your serpentine belt is squeeling. Make sure your AC is off (it also runs when you use defrost) and if it stops squeeling when you turn it off it is definately your serpentine belt. It may be worn out, or if it is fairly new it probably just needs tightened. When they are new they will strech some and need readjusted after a while. As a quick fix you could get a bottle of belt dressing (aerosol can) and spray in on the belt. Without hearing it my self I can't know for sure.

Dustin

[99XXXJ]

The Belt Is New. The Sound Is Coming From The Region Of The Transmission, T-case, Rear D-shaft. Sounds Like Metal To Metal "pinging" At Times.

[MagicRat]

Originally Posted by 99XXXJ

The Belt Is New. The Sound Is Coming From The Region Of The Transmission, T-case, Rear D-shaft. Sounds Like Metal To Metal "pinging" At Times.

I got the following quote from another Jeep website, where someone had the same problem. The following is that site's definitive answer on the problem.

It reads a bit like a confused stream-of-consciousness, but if you review it a couple of times you can get an idea of the problem and remedy:

I have had a LOT of experience dealing with jeep auto tranny's and everything in between! Your flex plate is essentially your flywheel but, since you have an automatic it's slightly different. Your flex plate bolts up to the crank on the back of your engine block. From there the Torque Converter bolts up to that. Your torque converter slides into your input shaft on your transmission. TRUST ME, if one of the bolts is loose on your flex plate or your torque converter you will get a good amount of vibration. It's because things aren't balanced properly because of a bolt loose. Once that balance has been defeated the flex plate will allow the torque converter to wobble very so slightly and you will hear an annoying scratching noise. If this continues you will crack your flex plate right where it bolts up to the crank. Once it cracks you will get a ridiculously loud tinging/scratching noise. I have audio clips of the sound if you want to hear them. Oh and if you do rotate your flex plate the best way to do it is on your harmonic balancer bolt. It should be in the center of the biggest pully towards the bottom of your block on the front of your engine. The nut should be a 3/4, use a wrench and not a socket because the fan will catch it when you spin it and make sure you spin it clock-wise. It gets tough on the compression cycle so wear gloves! Oh and by the way, you HAVE to pull out the transmission to thoroughly evaluate this to make sure it's not cracked! It's really not all that difficult. I recommend using two jacks. One transmission and one regular sliding floor jack. These damn things are really touchy. They're not all that strong but, get the job done as long as it's installed and removed properly. It doesn't take much to bend these things either I've found out. If you remove your tranny and DO NOT unbolt the torque converter FIRST and let it stay bolted up to the flex plate after the transmission is out it WILL bend it. Just the weight of the torque converter hanging by the four bolts will bend it even though it doesn't seem likely. It's designed to have the torque converter "floating" or not have any up or down force applied to it. Just back/forth/spinning force applied. Sorry for the long response I just don't want it to happen to anyone else since I've personally made all these mistakes and my jeep is now on it's 3rd,lol, yes THIRD flex plate! It's no f'n fun!

[99XXXJ]

Thanks alot. I appreciate your help. I am gonna get on this asap. Now I just wish I had a garage.