Hi all,

I'm a living in France and owning a 89 XJ 4L Automatic (pretty exotic over here and sold by Renault in those days )
I have spent significant time searching the forum and the web in general to identify my issue, without real success.
My problem: my car makes a very strong ratling noise. This happens in Park, in Drive and is strong reinforced when I'm uphill in an underground parking ramp for instance.
This only happen at idle or at very low speed and disappears when driving. The gearbox works perfectly fine when driving at normal speed.
I put the car on ramps and listened with an engine stethoscope. It clearly comes from inside the bell housing.
I checked the flex plate bolts, they are tight.
Can it be the sign of a broken torque converter?
Thanks in advance for your help!
NB: a noticed the gearbox oil level is too high and I don't know it's quality.

 

If the truck is sluggish taking off at low speeds, chances are you have a broken stator in the converter. If the turbine was broken, it wouldn't go anywhere.

 

The noise, file attached.
Indeed it really sounds like something is moving around or touching something.
The car does not seem sluggish taking off at low speed.

 

It’s possible the flex plate bolts are tight, but the flex plate itself can be cracked.

 

I agree, I have seen the center area around the crank bolts break out of a flex plate. Unfortunately the only way you can see in there to check is to pull the transmission which is a pain in the butt.

 

Thanks for your answers. I was indeed afraid that the rattling comes from a broken piece somewhere.
What is the risk to continue driving with a damaged flex plate?

 

If it cracks out completely, you will stop moving. Pull the inspection cover and shine a strong light up between the engine in the plate. You should be able to see cracks around the end of the crankshaft in the plate. Also look for scratches on the inspection cover if it was contacting the plate. Sometimes if the inspection cover took a hit from something, it could be bent back and contacting the plate as it turns. You should also check the bellhousing bolts for being tight. If they are loose, they will cause the plate to crack from flexing.

A good way to tell for sure is to take out the torque converter bolts and pry the converter back away from the plate, then try pushing the plate back towards the converter. It shouldn't bend easily. The good news is, to me, it doesn't sound like a broken converter.

 

Do this, and quit driving it.

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

 

^^^^ If I were you....I'd listen to this guy's advice on it... he know's what he's talking about.

 

I followed your instructions. (btw, thanks Cruiser54 I applied last year several of your grounding tips solving a couple of issues)
The flex plate does not show any visible cracks up to the center, I rotated it 2 times to be sure. So if its cracked, it's probably behind the center bolts?
I checked the 4 bolts connecting the flex plate to the torque converter, they are ok.
I'm afraid I will need to drop the transmission to see what happens...

 

Video with sound

 

Consider getting an inexpensive USB endoscope and take a look in there. Maybe somebody dropped a bolt in there at some point (like a CkPS bolt).

 

Or one of these guys has loosened up and is sticking/fell out.



From Bleeping Jeep

 

Stops starting actually, but same result.

 

This sounds to me like a bolt that has come loose, backed out, and is hitting rotating parts.