Knocking noises from the tranny area

He lately ive been noticing some dull knocking noises coming from under the area right behind my shifter in my '91 Cherokke sport with 5 speed manual, looking through here i've found the most common culprits to be loose t-case mounts or a loose exhaust.

does anyone know if either of these is the case? and if so how do i check/repair them?

thanks for any help
-Ryan

Atownatheist said:

He lately ive been noticing some dull knocking noises coming from under the area right behind my shifter in my '91 Cherokke sport with 5 speed manual, looking through here i've found the most common culprits to be loose t-case mounts or a loose exhaust.

does anyone know if either of these is the case? and if so how do i check/repair them?

thanks for any help
-Ryan

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I do know that the flywheel mounting bolts on the rear of the engine on 4.0 automatics (and I assume the 5 speed manuals too) come loose and make a tranny / rear engine knocking noise! It can cause the flywheel to crack too at which point it gets even louder.

Sounds like you on the right track. A good visual is hard to beat. Get under there and give it hell. Look for points rubbing etc. When you hear the sounds are you braking, shifting, or not moving at all. I once's stop a thump by pulling a cat off a water pump.

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badron said:

Sounds like you on the right track. A good visual is hard to beat. Get under there and give it hell. Look for points rubbing etc. When you hear the sounds are you braking, shifting, or not moving at all. I once's stop a thump by pulling a cat off a water pump.

Click to expand...

Now there is new one! Bet the cat wasn't too happy.:laugh3:

usually the sounds are right when i start the car, (and as it warms up they tend to go away) or when i am making a turn at slow speeds (i.e. taking a right or left at an intersection) and when i accelorate from a stop.

Right after i finish my homework im headin out to check the mounts.... lets hope its not to bad.

If heat makes it go away, check exhaust first. Check the collector/downpipe flange stud nuts, the catalytic converter flange nuts, and make sure the goophy little "exhaust mount" that attaches at/near the transmission mount doesn't have a loose bushing (that one has a tongue that goes through the bushing, and it slides back and forth. The bushing can wear out over time.)

Also, check the rear hanger - looseness there can cause noise transfer forward.

I'm also going to suggest that you check your u-joints, due to the symptoms you mentioned in your second post. Those sounds aren't usually affected by heat, but you never know (it would be a first for me - worn u-joints tend to be noisy no matter the temperature...)

my u-joints are good, as i just replaced them about two months ago due to breaking one of them. thanks for the idea though, and i will be sure to check the exhaust to.

For those of you who care it seems it was the exhaust pipping, it was loose and bumping around against the body.

im just glad it wasn't anything to bad.
:yelclap:

Was your exhaust only making noise when you were idling? I have some noise that could potentially be the exhaust or the transmission mount, I am not sure yet.
The noise only occurs when the jeep is in drive and i am stopped, when I accelerate the sound goes away.

It was the exhaust hitting the crossmember. As a temporary solution I wedged a hockey puck between the crossmember and the exhaust pipe coming of the manifold. Thats just a temporary fix. I ended up replacing the entire exhaust system from the manifold back to the cat. Good luck!