My 1998 xj 4.0 4x4 has a loud rattle/knocking sound. It is the loudest on startup and when it shuts down. While running it stops doing it or at idle it will rattle but irregular. While revving it stops.
Any ideas on what it can be?
No loss of power. Has oil pressure. Has oil in it. Can't tell where it's coming from.
here is a short video of it starting, running a few seconds and turning off.
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auto trans?
If so, likely flexplate bolts are loose.

https://www.cherokeeforum.com/f51/ho...ocking-125547/

 

That is exactly what it was. All 4 flexplate bolts were loose. Thank you cruiser54!

 

How did you fix it?

 

I'm in for the follow up on this one...because sooner or later could happen to mine. I've got the AW4 too

 

I make it a habit to remove one bolt at a time. Clean the threads on a wire wheel. Add LocTite to the bolt and re-install. Don't worry about using a torque wrench. It won't fit anyway. Just tighten the **** out of it with a long 15mm wrench.

 

Pulled the starter off and the bolts for the dust shield, pulled the dust shield out of the way enough to see up in there. Couldn't tell by looking but they were loose. Put a wench on one and it was loose. Turned the engine with a socket on the crank pulley to get to all 4 bolts. I just tighten them down. If they come loose again I'll go the loctite route.