Horrible Grinding Sound

HELP! I don't know what this sound is, but it sounds horrible!

Friend said it sounded like the bottom end of the engine, but it seems to have something to do with the drivetrain.

With it in gear, foot on the brake, giving it some gas to build up against the brake, it'll start grinding. Put it in neutral and give it gas, and it'll grind for a second, then stop grinding until you put it in gear again. So, it seems to only do it (at least pronouncedly) when under load.

I ran out and took a video of it a little while ago. In a lot of places you can't hear it because of wind noise, but I'd GREATLY appreciate it if you'd watch the whole thing and listen, because you can hear it quite well at a few places.



Any input would be greatly appreciated!!!

try a broken cv joint or u joint or something? i dont know. im not a mechanic.

Could it be your clutch fan hitting your radiator? If so, your motor mounts are shot.

haven't heard that before... but I'd check the exhaust pipe at the tcase crossmember. mine had a kinda similar rhythm to it when I destroyed some stuff a year or so ago.

I see it's an auto. Possibly flex plate has cracked out around the center where it bolts to the crank. Sometimes it fall loose and makes a racket. Sometimes it wedges into place and sounds OK?

Just a guess, I fixed an XJ that had this happen and it alternated between somewhat quiet and death warmed over.

Chris W

this the alt. ending to the blair witch project???

Sounds like exhaust could be rattling against the crossmember or something.

Or the electric fan maybe? Might be a reason for why the sound isn't constant.

Replace the Motor Mounts so the fan will stop hitting the shroud when it torques over ? ~Ace~

Thanks for the advice, folks!

Just as an update...

Took it to a transmission shop, hoping it was the flexplate or torque converter, realizing it could be the engine or transfer case or something else. They listened to it, put it on a lift, used a stethoscope, and proclaimed it has a knocking connecting rod.

Ok, that's bad news. It's knocking pretty loud...means that crank's gotta be chewed up a bit. But, HOPEfully not TOO bad and I can just replace the bearings for that connecting rod and get some more mileage out of it.

Met Dad for lunch, he rode around in it, just couldn't convince himself that it was coming from the engine from the way it sounded, so we took it to a Jeep specific shop. They finished lunch real quick, brought it in the garage, narrowed it down to the bell housing area, jacked it up, yanked off the dust cover, and viola...flexplate bolts were loose. Tightened 'em up and she's just fine!

So, I'd say that's a pretty happy ending. Oh yeah, and they didn't charge us anything!

Free service? Nice!

you need to take those guys a 12pk of beer or something, that first shop would have bent you over