clank! clank! clank!

Hey kids I got a 99 cherokee 4.0 AW4 and a 231. Making one hell of a clanking sound and I can't figure what in the name of heaven it is. Only does it in gear though.. or under load I should say. After about 1500 rpms it smooths out... it will do it in gear or if I. Turn the wheel all the way. No clue what it is. Sounds like its coming from underneath... maybe a rod bearing? But only roughly 140k on the ticker... any help here guys? (New fluids also)

Well, a rod bearing isn't going to change depending on the position of the steering wheel.

You say it only does it in gear or under load. When you say in gear, do you mean moving in gear or just sitting?

How steady of a sound? Does the sound vary with RPMs?

Have you checked the torque converter to flexplate bolts?

Sounds like a bad front axle U-Joint to me. Crawl under the front to twist and shake the joints at the axle ends. If there is ANY play, they are bad.

If im just sitting there stopped and I put it in gear it will start. Yes it is variable with rpms. Its a pretty steady rattle. Imagine taking one small bolt and placing it in an old tin folgers coffee can and rattling it around. One I hit about 1500 rpms it stops.. no I have not checked those bolts.. haven't the slightest clue how to..

Underneath there is an inspection plate at the bottom of the bellhousing, two bolts, pull it off and you have access to the torque converter to flexplate bolts--it is common for them to work loose and start making noise.

Is it a tight squeeze? And how tight should they be? And pattern I should tighten them? Just want to do it right. Thanks joe

Not a tight squeeze, four bolts. Not sure what size your year has, 10mm or 12mm, but the FSM 90 has the 10mm torque to 25 ft lbs and the 12mm torque to 42 ft lbs. Use some Locktite on them.

If you pull the spark plugs it makes it easier to turn the engine over from underneath using a big screwdriver or prybar. I would draw them all down fingertight and then torque alternating like a cross, up/down/left/right.

Good luck.

OK thanks Joe I will give it a whirl here in a bit. I will post back results

I had a loud clank when my power steering pump when bad. Sounded awful and was almost impossible to pinpoint sound wise. Didn't replace it myself, so some local garage guy could have straight lied to me. Mine would quiet down a little at higher RPM's, and it made sense to me that it would be a belted part.

I only mention it because you said you hear it at full steering lock. All the posts I read diagnosed the sound as flexplate or torque converter. Good luck.

XJ-CJ8 said:

I had a loud clank when my power steering pump when bad. Sounded awful and was almost impossible to pinpoint sound wise. Didn't replace it myself, so some local garage guy could have straight lied to me. Mine would quiet down a little at higher RPM's, and it made sense to me that it would be a belted part.

I only mention it because you said you hear it at full steering lock. All the posts I read diagnosed the sound as flexplate or torque converter. Good luck.

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FYI:

Locating sounds in the engine compartment can be made easier. Keep a 3' section of vinyl tubing in your "kit". I.D. of about 1/2" or less. Stick one end in your ear and move the other end around the engine compartment--Warning: moving parts and your flesh/clothing are not a good mix--you will be able to isolate the source of the noise.

joe_peters said:

Well, a rod bearing isn't going to change depending on the position of the steering wheel.

You say it only does it in gear or under load. When you say in gear, do you mean moving in gear or just sitting?

How steady of a sound? Does the sound vary with RPMs?

Have you checked the torque converter to flexplate bolts?

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My bet is the torque converter bolts also.

My engine sounded like a piston was going to escape very shortly when I started, accelerated, decelerated, idled, or goosed the gas... basically anything except cruising steady. It was so bad that the response from one of my local chapter members when he heard it was to yell "oh my GOD!!!" and take a couple steps back.

I just cranked em down as tight as I could with a gearwrench... I seem to recall using a 15mm flex head one (the 10 and 12 mm numbers above are probably bolt diameter.) No loctite, nothing, just cranked the crap out of em, I didn't bother with doing it in the right pattern either. I would have done it right, but the whole shebang is coming out in the near future so I can put a 4wd AW4 and a transfer case in, so there is little point, it's getting replaced anyways.

PS, there is one stupid bolt that Chrysler put in from the "wrong" side, when you take the nut off it will still not come out because the exhaust downpipe is in the way. Grab the end with a pair of vise grips to keep it from spinning and chop the head off with an angle grinder or sawzall, then put a new one in... doesn't really matter what type, size, or grade so long as it fits the hole, those bolts are under almost no stress, they just hold the inspection cover on.

Oh, and a :gee: trick to get them all done with a minimum of crawling out from under the jeep - disconnect the ignition coil so it won't start, and while lying under the jeep use your wrench to jump the starter solenoid to "bump" the engine forward to the next one. Use a paint pen to mark the heads of the bolts you have already tightened and keep your hands, hair, and clothes away from moving parts when you do this, oh, and I'm not responsible if you light it on fire with the sparks and burn your whole town down, nor if your friend drinks all your beer while you are under the jeep for too long due to using this trick.

I just did a half donkey job on it to see if that was it. No loctite or nothing just tightened them some. Sure enough it quieted right up. The noise is still faintly there but now that I know what it is I can go back down and correctly do it. And I just ignored the backwards bolt and just bent the plate up haha. Straightened it out and all just nice. Thanks all for your input

Glad you located it and don't forget the Loctite--also, make sure you clean both surfaces of any contaminates or the Loctite won't set up correctly.

joe_peters said:

Glad you located it and don't forget the Loctite--also, make sure you clean both surfaces of any contaminates or the Loctite won't set up correctly.

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hahahahaha

OK, I'll call BP and ask what they're doing on the gulf coast... and then double it. The loctite might have a chance on my bolts then :dunno:

99_XJ_ - glad it worked :thumbup:

One last note- Joe, the 3" vinyl tube is the handiest thing ever! I can pinpoint lots of sounds under the hood and also I can figure out which neighbor is cursing me over the sound of my air compressor :soapbox: I will be sure to share this with other members (along with the saftey disclaimer)

kastein said:

My engine sounded like a piston was going to escape very shortly when I started, accelerated, decelerated, idled, or goosed the gas... basically anything except cruising steady. It was so bad that the response from one of my local chapter members when he heard it was to yell "oh my GOD!!!" and take a couple steps back.

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Yeah, I was a bit disconcerted by that at NACFest, wasn't I? :wow:

Glad to hear it wasn't actually a rod bouncing off the inside of the block. Guess you're not carrying the spare engine, trans, and tcase in the bed anymore then?