Sup everybody.

I've been a service mechanic for years, and I tinker with motors on the side, and I Just bought my first XJ, It's a 1996 cherokee sport. It has 158k on it, and I've had it for about 1000 miles, and it runs GREAT. Two days ago, it started making a noise that sounds like either a rod is knocking, the flywheel is cracked/loose and shaking back and forth, or the torque converter is loose. The oil is clean, and it starts perfectly.

Here's the wierd thing.

If I let it sit and idle, the noise continues. If I rev the engine up to about 2500rpm it speeds up. Doesn't get louder, just faster.

If I put it in drive, and drive off (I drive gently) after about 100 yarts, it almost goes completely away.

If you stop, and roll the window down, or get out of the jeep, you can just barely hear the noise, but it really sounds perfectly normal.

If I turn it off, and crank it immedeatly, it does not make the noise. If I let it sit for 5 minutes then crank it, it starts the whole process over again.
I'm changing the oil in it tonight and putting 10w-30 in it.
Has anybody seen this before?
And how hard is it to check the flywheel/torque converter bolts?

I'd appreciate any advice/suggestions

 

Sounds to me like a cracked flywheel!! Happened to my 89'!

 

I would check your flexplate, often enough a crack in the flexplate will cause a tick similar to the one you are describing.

 

Well, how hard is it to drop a trans on a cherokee?

 

Well, I fixed my problem.
Not entirely sure what it was, but it's fixed.
I was driving down the highway on the way home, and it had stopped it's knocking by then, and I was driving past a very long, steep hill with a trail up it, so I pulled in, put it in 4Lo and went right up without so much as a squeak from the drivetrain.

Now it's gone. I doesn't do it when I crank it up in the morning, or when I leave work.
Anyway, thanks for the help!

 

I would still pull the inspection cover and using a prybar check that flexplate. You ever heard about the calm before the storm? Well the silence may be that calm. Just be safe because a split up flexplate can be very dangerous to you and anyone in the vicinity if it frags. Don't ask me how I know.

 

Well, it ran perfectly for two days, without a sound, and yesterday when I was driving down the highway, it threw a rod through the oil pan. number 6 cylinder. Never knocked, or rattled, it just went.
Craziest thing I've ever seen.

BlueXJ, you were dead on, it definetly was the calm before the storm...

Getting a used motor put in monday...

 

Wow sorry to hear about your problems, but at least you are getting it taken care of and hopefully you will be back on the road in no time.