2001 Cherokee Sport started making the classic loose Torque convertor bolt noise.
Got under it and found 3 of 4 bolts loose.
Tightened them, and the noise went away, but spotted the flex plate was cracked around the crank tail.
Set aside time, pulled the transmission, removed the old flex plate and confirmed it was cracked.





While it was out, I pulled the oil pan, did the rear main, and oil pan gasket, and trans service.


I got it all buttoned up yesterday.
Left it up on the jack stands so I could check for leaks etc.
Started it, and there is a noise from the bellhousing area.
Kinda like the loose torque convertor bolt noise I had to start with!
Immediately stopped the engine.
Crawled under, and began to investigate.

First thought was that the Bellhousing cover plate was touching something.
Turned the crank with the front pulley bolt, and at a certain point I hear a slight grinding noise.
Not hard, just a noise like the flexplate is touching something.
Removed the cover plate… still makes the noise when turned by hand.
Rotated the motor and double checked all the convertor bolts. All tight.
I go to start the engine again and the starter makes a weird grinding noise, but it starts.
Crawled under and listened… def flexplate area, and it’s loud.
I’ve had a similar starter noise on my Chevy after I fitted a new starter, and I had to shim the starter… this sounds similar.
Removed the starter, turned the motor by hand. Still a grinding noise at the same spot.
Not the starter alignment then.
Reinstalled the starter, and tried to start the motor and it made a grinding noise, and then just made a click.. wont start.
Sounds like the battery is flat or starter jammed.

My gut is there is something wrong with the flex plate.
I read somewhere it’s possible to get the wrong one…
Bought it from Rock Auto… they only list 2 flex plates for a 2001 Cherokee, and there is no options… just says 13.81” diameter.

Could I have made a mistake mounting it?
I wiped down the crank mounting face, offered up the new flex plate, rotated it until all the offset bolt holes lined up, did the same for the washer, and got all the bolts in, locked the crank, and torqued them to spec.
If I’d got the flex plate misaligned, the motor wouldn’t start, would it?
Because the crank sensor would not read it correctly.

What else?
The Torque convertor did ride forward in the trans while It was on the transjack, when I was trying to refit it.
But I could not get the bellhousing close to the mounting face... I realized what happen, pulled the trans back, and rotated the Convertor a couple of times, and it went back in.
The Torque Convertor was fully seated in the transmission before I offered it up(about 1/2” back from the bellhousing face.
By mistake, I did not get to doing the the Convertor bolts until I had the trans bolted up, and could not get the flex plate to rotate without moving the converter too.
I backed the bellhousing bolts out a few threads, and it was free, so I was able to get them lined up, no problem, and in fact had to pull the trans up tight to be able to thread the Convertor bolts in...
I dont think the Convertor was unseated from the Trans pump...

At this time, Im baffled and confused, and need help and advice!

 

Wish I could help but don't know. Just wanted to say this is one of the best described and detailed comments of a issue that I have read in a while! Thanks for that.

 

Thanks!
I do my best to give detailed and accurate info, cos I've found thats the only way to get a detailed and accurate answers.

Went to look at it today... and the battery is COMPLETELY flat.

Wondering if the starter is jammed, if that drained the battery...
Mmm.

 

The two different flexplates are for the old renix or the newer HO. They had different windows and were not interchangeable - well you could but it wouldn't run. I just gave a guy on reddit the bad news that he swapped in the wrong flywheel and he's gotta pull the tranny and clutch back out.

 

My observations would be that if there is a grating noise when the engine is hand rotated, that will not go away

furthermore, when I changed trans, I measured the depth of the TC when fully seated back from the bell housing with a straight edge and the distance to the bolt flats was ~1"

Its difficult to avoid the conclusion you will need to back the trans out, remove the flexplate and measure it against the old one

You can examine the TC tangs to see if they are damaged

with those parts out you can rotate the engine and make sure the noise is not present

 

How about removing the starter and cranking it by hand?
You didn't remove the aluminum plate between the engine and trans while it was apart, did you?

 

Thanks for the input guys.

Ok, that’s put my mind at rest for the wrong flex plate!

Yes, I took the starter out, and rotated the engine by hand… that where I could hear the grating noise.

I did check the engagement if the TC, as it had slid forward.
The bolt faces were about flush with the bellhousing mounting face, before.
I spotted that and I’d read about 1/2” back was right, so I rotated it some and felt it engage the pump, and slide back in.

Yes, I did remove the aluminum engine plate, while the flex plate was off, and cleaned it up….
It was put back on before the flex plate was bolted up, and it can only go back on one way… with the starter hole to the passenger side, and the open section down.

I was having trouble with locating it when I offered the transmission back up, so I swapped the dowels, from the Trans(where they had stayed), to the engine, so they would hold the engine plate in position.

 

If the torque converter is fully seated on the pump when the trans is mated to the engine, there will be ample space between the flex plate and torque converter. So much so that the torque converter would need to be pulled by hand toward the flex plate for the bolts to thread. If the torque converter was hitting the flex plate when the trans was bolted in, the TC is not seated on the pump teeth.

 

I'd maybe unbolt the t/c and push it back, and rotate again by had to see if the noise is still there. Measure the flexplate at a few different rotations to see if it's crooked too.

 

Thanks Guys,
As hard as it is for me to accept, I think the last two posts are probably the most likely scenario.
If you were in my shoes, what would you do... order up a new flex plate?
Order a new TC?

 

I unbolt the flexplate and spin things. That'll tell you what side of of the line the problem is on - flexplate or tc/trans.

 

If you do end up pulling it, check the pump teeth and inspect or replace the seal. Like Lawsoncl said, unbolt the TC and see if it’s jammed against the flex plate.

 

Really weird.
Got the trans ready to come out.
Turn the motor and I hear a grating noise.
Take the torque convertor bolts out and the noise is gone.
No sign of wear or touching on the bolts that I can see.
I guess at this point I have to pull it back and try to see where it’s touching.
With the bolts out the convertor is not touching the flex plate so it must be correctly set. Just weird

 

I'm mid flexplate replacement as well on my '98. Looking at Rockauto for '98 they list the Z337 ('98 OEM equivalent PN 52118551, not sure what the OEM PN is for 01) so I bought this and like you mentioned, fit seemed ok for me and overall dimensions matched up with the removed plate. The windows were slightly different in amount and placement but the 4 needed for the TC bolts lined up, just a few extra on the new plate. Currently the new plate is on and the bellhousing bolts are on, i haven't bolted the flexplate to the TC yet though so I will give it a spin by hand this evening to see how everything sounds and report back. Based on this it sounds like i'll be bolting the TC bolts next and giving it a spin. Sorry you're going through that, it's a bear of a job pulling that thing back out again.

 

I think I found the problem.
Pulled the transmission, pulled the flex plate and didn’t see anything obvious.
then I noticed this gouge inside the trans casing.





Then I looked closely at the flex plate, comparing old with new.


See how the new one flares out at the timing ring.



Then I measured the height from the ring gear to the top
og the timing ring.
Original one is 1” roughly.
new one is 1 1/8” plus the outward bell shape, and I think it’s touching the trans casing.



That’s the only thing I can think of.