spudkelly

I have a 2000 Cherokee w/ 140K mi on it. I'm getting a ticking noise while driving and have determined that it is probably not coming from the engine or the exhaust manifold. Here's a rundown of the tests I ran:

1. Makes noise while driving (reverse too)
2. No noise in Neutral or Park
3. Makes noise while in drive (or reverse) with parking brake engaged...and revving engine
4. Transmission Fluid is in great condition and to proper level (checked while running and warm..in park)

My thoughts are that it's either a U-joint, something in the transmission, or transfer case(?). Can someone tell me how to narrow this down, or just voice general opinion about other causes.

Thanks,
JK

Throttle Jockey

tough call on this, if i had to make an educated guess, i would lean towards a lifter tap, as you only get the tapping sound under a load, (in gear) you could check your convertor bolts just to make sure they aren't loose.

Abovetimberline

Just a couple of suggestions,seeings you do not think it is the motor,Check your flex plat for any cracks coming from the bolts,this will cause a sound like you describe,and check to make sure your starter is not hitting the starter,I would also check for anything that appears to be shiny underneath where something could be hitting.

Mike1998XJ

X2... Flex plate inspection in order!
Mike

spudkelly

Guess I'll be checking into the flex plate...Is this a common issue?

Abovetimberline

I have seen enough to say it happens,common not sure. The first time it happened to me I exsplained it to my friend what I was hearing,he put it up on his lift and within a minute showed me a hair line crack off one of the bolts. Mine was a bit louder than a ticking sound and generally happened when excelerating.

Mike1998XJ

Too bad someone couldn't record a few of these cracked flexplate sounds. It would make it nice to have 3 or 4 recordings from mild to real loud...
Mike

Abovetimberline

Mine sounded like the drive shaft shaft was hitting something,in other case It almost sounds like a rod bearing,if that helps,it is not exactly a tick,but I think a lifter is a tick.

winston427

Mine started as a very light tick that quickly developed into a symphony of hammers in the lower end. What I thought was I self destructing engine turned out to be a broken flexplate. I pulled the inspection cover and found tiny cracks coming from the center. After the trans came out the story changed.....



into a completely seperated center section.

Mike1998XJ

Does the bad rod bearing sound like a thunk-thunk-thunk? I can't remember, it's been a long time since I listened to one.
I think I'll inspect the Flex plate on my DD tomorrow... I am starting to hear a sound kind of like when you were a kid and put playing cards in your bicycle spokes and rode slow. It is very slight. I start to hear it around 15mph and then hear it all the way up. The noise never really increases. I can feel the feedback when I place my hand on the TC shifter. I feel it to a lesser degree when I place my hand on the Automatic shifter. That TC shifter has the rattle in it when you pull up to a stop.
Not trying to hijack the thread... I hope to help the guy with what I find.
Mike

spudkelly

Originally I was pretty sure this was not a lifter 'tap'...I was wrong, it was. After investigating the tap, trying different additives to pump the lifters back up, and getting small improvements I thought it was something I could live with. 3 months later I spun a rod bearing. My mechanic said that with the lifters ticking that I could have gotten metal shavings into the oil eventually damaging the rod bearing. If I were to do this again I would've fixed/replaced the lifters immediately, ($100 to do it myself, $700 at the shop)..instead of $4500 for a new motor.

Thought I'd share...

Anyone want this thing? I'm accepting offers until I figure out the best thing to do. Replace/repair/ride bike.