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Knocking sound coming from in between engine and tranny???

R

R680

NAXJA Forum User
Location
United States
At idle there seems to be a knocking (rhythmic and continuous, "knock-knock-knock" at idle) sound coming from between the engine and tranny inside the bell housing. When I pick it up off of idle it seems to make up the "slack" and stops the knocking, yet if i let off of the gas and blip the throttle again it sounds off with one knock...again like it is making up slack or something??? I have a '92 4door xj with 4.0 and 231 with aw4. if that helps at all...could it be torque converter or something? I appreceate an y replies....
Regards,
Stumped...
 
I have had a similair problem and it turned out to be the flywheel bolts coming loose. Take a look on your transmission and see if you have an inspection plate (I do not). If you do you might be able to get a wrench in there and check the torque on the flywheel and the torque converter bolts. Either way that sounds like it is one of the two. Good luck
 
i had the same problem. take the inspection cover off and tighten the four bolts back there. you can only see two at a time and have to rotate the flywheel to see the others. three of my four were loose and would hate to see what happened if they all came off. total work time was a hour nice and easy.
 
i 3rd that diagnosis..... pull them out.. clean real well.. 2 words LOCK TITE.. my problem has not returned...
mike
 
Mine has made that noise for months now. Is it the bolts from the crank to the flywheel??

Does the 96 AW4 have an inspection cover?
 
naw thats the bolts from the flywheel to the torque converter, usually, I think they all have a plate.
 
So I'm a total noob, but I'm pretty sure I've been having this very same problem. I know very little about my XJ's engine, but I'm, uh, adventurous. Please be patient with me.. ;b So, the transmission is mounted under the vehicle, right? Is the inspection cover you're discussing located roughly below where the gearshift would be in the cab, but on the underside of the car? Essentially the steps you're all advocating involve removing the inspection cover on the tranmission, identifying four bolts, and tightening them? It sounds manageable -- I heard one person say it takes about an hour. Is this something a newbie could do? Am I completely wrong in my above assumptions?

Thanks. ;b
 
Don't worry about being a newbie...this is the place to learn. The access plate is on the bell housing, not on the transmission. The bell housing is a big, tapered tube between the engine and the transmission. It holds the torqueconverter inside it, and matches the engine to the transmission. A shop manual will help you if you plan on wrenching on your jeep. The factory service manual for your year (nearly $100) is by far the best, followed by Chiltons then Haynes (because Chiltons has a a few more wiring diagrams). I have a wrong-year FSM and a Haynes, and use my public library Chiltons Truck 1989-1991 for my '90. 4xBob
 
Yep that sounds familiar. one hour average, kinda depends on mechanical skills. I could put up some pictures tomorrow if anyone needs. PM me and I'll take some. anyway not a hard fix. but that's almost definitely what that sound is.

.02 Daryl
 
It,s not a hard job.A 13mm off-set wrench(IIRC) or socket will do.Use Blue Loc-tite on the threads and mark the bolts so you don,t miss any.
Use a long screw driver as a pry bar to turn the flywheel.
HTH
Wayne
Torque on the bolts is 40 ft lbs,good luck with that
 
You guys are awesome. Thanks so much.

Re; the guidebook I should be going by. Think I can scrape by with a Chilton's and pick up the factory manual when I get a chance?

I haven't got much in the way of mechanical skills but I've done a couple things well: I've watched other savvy folks work on vehicles as much as possible and I've tried my best to keep an open mind. I should have the wrenches to get the job done -- I had to pick up a set 'cause it was just getting to be too much to squeeze into tight places with a crescent wrench to do basic stuff like changing out tail lights.. ;b

Alright. Will take into account all you folks have said, and when it's just about 10 degrees warmer outside I'll take another look about and so on. Thanks again.
 
Ok. I have a 2000 4X2 that I think might have this issue. There I got under it to investigate a knocking type noise and it seemed to be comming from the bell housing. Being the good person that I am I turned to the AW4 section in my Jeep hymnal and noticed that there is a special tool called out for 4X2's when installing the dust shield. Is this the cover that needs to be removed or is this another cover? If it is the one why do I need a special tool D-187-B...and what is it?

Kenny
1987 & 2000 XJ
 
8700XJS said:
Ok. I have a 2000 4X2 that I think might have this issue. There I got under it to investigate a knocking type noise and it seemed to be comming from the bell housing. Being the good person that I am I turned to the AW4 section in my Jeep hymnal and noticed that there is a special tool called out for 4X2's when installing the dust shield. Is this the cover that needs to be removed or is this another cover? If it is the one why do I need a special tool D-187-B...and what is it?

Kenny
1987 & 2000 XJ
Click to expand...

I can't imagine that there would be a special tool for this job. unless it's a tool to hold, move the fly wheel. as it is there is only one, maybe two of the bolts accessible thro the cover on the front of the bell housing. and the fly wheel has to be held in place to tighten them then it has to be turned to gain access to the next bolt. But that was on my 91 4x4. ? so who knows?....
 
The manual reads "On 4X2vehicles, install the dust shield using special tool D-187-B"

I have never taken a bell housing off of any of my Jeeps but to me it looks like something a wrench and /or a rachet can handle.

Kenny
 
It did not seem to be brain surgery. I was however wondering about the starter. Oh well it's just one of those things that needs to be done. I wouldn't own two jeeps if I did not want to work on vehicles.

Kenny
 
since we're talking about tranny noises...the auto tranny in my 98 will start making a knocking sound after i run it in 1st gear for a while. it's almost like the fluid gets hot and thins out, causing the noise. anyone else hear of this? i've been contemplating a tranny or tranny/oil cooler to try and solve this. any thoughts?...
 
A thought -- by all means first checkthat the torque converter bolts are tight. If they are, then the problem is likely a cracked flexplate (flywheel). They do crack -- I replaced the one on the "Montana-mobile" and I could not understand why it didn't blow up. The crack was an annular (circular) crack right around the outer diameter of the reinforcing ring where the flywheel bolts go, and the crack extended about 2/3 of the way around the hub.
 
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