ZombiePopper

Boy do I have a riddle for you guys lol.
Ever since I bought this ZJ there's been a "tapping" from in/under the thing.
(Because it was running so bad it was hard to diagnose. But now that it's running better, I can clearly hear it but I can't diagnose it. And I can't hear it while I'm driving it at a decent speed, it's not very loud and I can only hear it at low speeds, stopped, stop and go traffic etc.)
Here are the symptoms;
-Only taps warm, when it's cold it doesn't tap.
-doesn't tap in reverse, completely disappears the entire time I have it in reverse. It immediately stops the instant I put it in reverse. it still taps in Drive, park and neutral when warm.
-while laying under it sounds like its behind the engine or under the jeep but it doesn't sound like an ex leak.
Any ideas?

ZombiePopper

Am I the first guy to have this issue?
Just my luck lol
I'm suspecting the trans. (?)
But it goes into and out of gear smoothly, quietly and shifts thru all the gears 1st-overdrive.
No noises or odd behavior.

ZJMAX

Common things are Torque converter bolts need to be tightened also it's common to have a cracked flexplate.

Max

dave1123

Check your trans mount.

ZombiePopper

Thanks Dave and Max!
I was thinking about the TC bolts or flexplate but dismissed it because I thought it would still tap in reverse if either one of those were the issue but I'll pull the inspection cover and take a peak. Def doesn't hurt the check them and while I'm at it I'll check out my trans mount.
I appreciate the input guys!

dave1123

USUALLY, when the torque converter bolts are loose, it will only knock when it's running with no torque on the transmission, as in neutral or park. It usually shuts up when engaged in ANY gear.

I had a friend who used to hot-rod his Pontiac Firebird. I mean drive it always it the limits. He pulled into my driveway one day and it was rattling badly. We investigated and found only 1 bolt was still in the flexplate and that one was loose! It had worn out the hole so bad we had to put a washer under it. We found the other 2 bolts, one in the bottom cover and the other resting on top of the block flange behind the flexplate. We had to buy 3 new bolts because the threads under the heads were whipped. We should have changed the flexplate, but he drove it another year with the washer under the one bolt.

This was a Firebird 400 that he used to street race. With one bolt! That's why I liked GM. You could beat the crap out of them and they'd take it. This was also late 60's.

The reason I suspect the trans mount is because when mine went, the tailpipe would bang on the crossmember.

ZombiePopper

Excellent point Dave, and I was thinking something similar, I'm also a fan of the 70-73 'birds.

But here's an update;
I've been doing basic maintence to this ZJ, and it only taps in park, hot or cold now, it taps in park, BUT, the tapping immediately stops in neutral, reverse and drive but as soon as I put it in park the tapping starts again.

Funny thing is, I haven't been actively doing anything related to fixing the tapping yet lol, stuff like; new PCV valve, new breather, trans fluid/filter, o2 sensor, etc etc but the tapping seems to be stopping on its own????
The only thing I've done is loosen the inspection cover bolts, which is a big clue, I think?
I'm loosening the starter bolts tomm to see if I can wiggle the inspection cover out and check the convertor bolts.
I'm not seeing any shiny rub marks and the trans, t case, motor mounts etc all seem solid.
But I'll update tomm after I pull the cover.