Flex plate wobble issue

[DaveB]

We just swapped a newer 4.0 into my son's comanche and it fired up great but we had clanking sound of flex plate bolts hitting the dust shield. I took out the four torque converter bolts and the noise went away. I noticed the flex plate was wobbling a bit with the torque converter hooked up but the flex plate really wobbles when the TC bolts are out. We pulled the flex plate out and it looks like the bolts were hitting the dust shield slightly. I took his flexplate and used a dial indicator to measure wobble and got about .035" of wobble spinning it with no load. So as at test I took two other 4.0 flexplates and measured those. They ended up having as much as .080" of wobble. This flexplate wasn't ticking with the old engine and I doubt we bent it taking it out. I can't see any cracks on it and it isn't that old. Does anyone know how much wobble is normal ? I would like to know before buying another one.

 

[RockChucker]

maybe this will help?

http://www.jeepforum.com/forum/f8/flywheel-flex-plate-woes-1238722/

i just searched for 4.0L Jeep flex plate runout...

 

[jmaxj]

you got loose bolts?

i know it sounds stupid but mine was doing the same thing once and i pulled the inspection cover and stuck a wrench on the bolts and found even though i couldn't move the plate or bolts by hand the bolts moved quite a bit with a wrench. they were pretty loose.

 

[DaveB]

maybe this will help?

http://www.jeepforum.com/forum/f8/flywheel-flex-plate-woes-1238722/

i just searched for 4.0L Jeep flex plate runout...

I searched last night and found that link too. I also looked for bent flexplate and found lots of posts. Some said a bit of wobble was normal others said no. I did find a post that said to never use an air wrench to mount them as it will warp them (my son did use one). I also looked at the dust shield where it was rubbing on the torque converter bolts and it was bent in a bit. I think this may have been part of the problem but I don't want to put it all back together and have the same problem.

 

[DaveB]

you got loose bolts?

i know it sounds stupid but mine was doing the same thing once and i pulled the inspection cover and stuck a wrench on the bolts and found even though i couldn't move the plate or bolts by hand the bolts moved quite a bit with a wrench. they were pretty loose.

I checked them and they were tight.

 

[DaveB]

Well we broke down and bought a new flex plate and were very careful torquing it on. We did it like you torque on wheels with a cris-cross pattern. I also used a different dust shield and it no longer has any clanking going on.