xjfleet

Hello CF,

New here. My 2000 XJ has just started with a knocking noise after driving 15-20 miles. About 20k miles ago I had found that the flex plate bolts were loose from an engine replacement(forgot loctite). I had just checked the bolts today after this knocking noise started and they are fine. Is it fairly easy to spot these cracks on the flex plate or do I need to remove the tranny? I just had tranny flushed with no avail still knocking. The knock seems to be intermittent as well, sometimes there and sometimes not and only happens when warmed up at idle after driving. New tires were also put on and new alternator just before recent oil change, which needed to be drained for overfill by dealership. If cracks can be detected can the jeep be driven until I can afford to take time to replace or is this a no drive situation? thanks in advance for the help!

Fsher21

Welcome to the forum!

As long as you checked every bolt and it was fine, I would double check all your exhaust mounts to make sure they didnt rust out and allow for it to rattle. I dont know what a cracked flex plate sounds like, but the noise is different than loose bolts. Check youtube videos of cracked flexplates and see if it sounds like yours. I think a visual inspection of the plate can be done with a good light, by spinning it the same way you did to access the bolts.

xjfleet

I am planning on checking plate for cracks tomorrow. I can now make the noise by placing jeep in gear foot on brake and rev engine slightly. Is this a good indication there is a crack in flex plate?

Bustedback

What is your oil pressure? You can look up inside the inspection cover at the back of the engine and see if there is any rusty dust around where the flexplate bolts to the crank, that dust is a sign of metal rubbing metal and could mean there is a crack(s). The flexplate usually cracks around the center by the crankshaft.

xjfleet

Oil pressure is 60 psi cold and 30-40 warm

xjfleet

Will i be able to see cracks near crank thru inspection cover?

Bustedback

Maybe not cracks, but the rusty metalic dust is a sign of a crack.

mud-dog27

it depends how big the cracks are, i was only able to see one crack from the inspection cover, upon full removal of the transmission i noticed there were actually 6 cracks spidering out from the center varying from half inch to a couple inches

BotakBeng

This is what you see when you remove the inspection cover.
When removing inspection cover, there is a bolt on the driver's side which hit the downpipe, just loosen that, and bent the inspection cover.
Rotating the crankshaft will let you turn the flex plate....check for loose flex plate bolts and cracks.

No need to drop the oil pan....i was doing my RMS when i took the pic.

GL.

xjfleet

Well i found cracks yesterday, one was going around where bolts for crankshaft is and one was going down towards tc bolts. Glad its nothing engine related but srill set me back 500 bucks

BotakBeng

If you wanna get your hands dirty....i'm sure you can do it for lesser.
I have no idea how to replace it but i'm sure someone do.

GL.

xjfleet

Got jeep back from shop, dont have tranny jack. Travel with this jeep 1200miles per week so needed in a hurry. Flex plate cutout like cookie cutter in center and cracks going straight down out towrds csps ring.