Save the kittens, and keep my wife from killing!!!

[Caged94XJ]

Ok so here is the deal... Just got a "New" 111k motor to put in my 97 XJ. After getting it I replaced the following:

Rear main gasket
Timing cover gasket
Valve cover gasket
Oil pan gasket
Oil filter adapter seals
Welded the exhaust manifold cracks

Fired it up and it was perfect not a sound. Drive it less than a mile picked up my trailer, no noise. Drove less than a mile with trailer, still nothing. Drove less than a mile with trailer, again nothing. Unhitched trailer started Jeep and it has a knocking noise. Can only make it do it on first start up then quiet, and between 1,000 RPM and 2,000 RPM. Motor runs perfect no shakes, no pulsing, just smooth. So what the heck could this be?

I pulled the flywheel cover and there is no signs of rubbing and all the bolts are tight, and fluid levels are perfect. Help me before I have to go on a kitten kicking rampage, and my wife hunts down and kills the prior engine owner.

 

[Led]

4.0 knock duh mine all did that

 

[Frank Z]

I talked to Mark about this, I sold him the motor.

The noise is cyclical, doesn't seem to be coming from the motor. I suggested double-checking the torque converter bolts, not sure if he's had a chance to do that yet.

 

[Caged94XJ]

I trust Frank Z 150%, so I know this motor is good. But I need to find this noise and fast.

 

[UnlimitedMatt]

Is it possible that the flywheel has a crack?

 

[Elguapo]

Post a video of the sound. Or take it to a shop for a diagnostic.
Good news is the sound isn't steady. Have you dropped the oil pan to check for metal shavings. Or removed the pan to see the rod bearings?

Btw ur emotional, calm down and figure it out. Lol

 

[Caged94XJ]

When I had the oil pan off I checked everything. It was all solid and this motor was as clean as they come.

 

[Caged94XJ]

Can you start a 4.0 without the torque converter bolted up without damaging it?

 

[YELLAHEEP]

Probably not a good idea.... You can push the TC back some but if any part of it contacts the spinning flex plate..... Could be disastrous.

 

[Caged94XJ]

Well the problem is solved... Cracked flex plate!!! Frank Z thank you so much for all your help on troubleshooting this one.

 

[xj-grin]

Kittens ok?

 

[UnlimitedMatt]

Is it possible that the flywheel has a crack?

Woohoo! Look at Matt with the big brain.

Do I win anything?

 

[xj-grin]

Flywheel, flex plate, potato, potaato... :eyes:

 

[Frank Z]

Glad to help, sorry I don't have a spare one for ya.

Troy?

 

[YELLAHEEP]

Yup...... I have a few.

 

[jimgrms]

Woohoo! Look at Matt with the big brain.

Do I win anything?

Yeah the kitten of your choice !

 

[Caged94XJ]

The kittens are safe for now.

 

[souske]

Pics?

 

[Elguapo]

Thank u jebus that the kittens will make it

 

[Caged94XJ]

Ok, final replaced the flexplate and the knock is gone, but now it is acting like it wants to die off and on at idle. And when you drive it is surges and the RPMs jump when it does. So what the hell is this now?