Bent flex plate vs. Torque converter noise issue.. (1 Viewer)

[Kief]

So, I just dropped in a freshened up 1fz-fe into my 93 from a 94 and used the flex plate off of the new-to-me motor. I used the old tranny and torque converter and when I get underneath while its running I hear a cycling rattle near the flex plate. I noticed some missing bolts from the PO's attempt to drop the tranny but I don't know how far he went before I pulled it. Now I wish I had used the old one. I torqued all the flex plate bolts to spec and the FP bolts to the torque converter as well.
What will this do to the torque converter or will it matter? Would rotating the FP have any affect? (the manual says to mark it for alignment upon reassembly)
I wouldn't kill to drop and pull the tranny to swap'em but dang, I just got all that in there!

 

[Dave 2000]

It sounds as though the flex plate is buckled or even cracked. When they crack it can be so small that you would not notice it without a good close up look.

Note I am not an auto trans 'clever' person but have swapped more than a few auto transmissions/engines on Jaguars and the sound you describe does sound flex plate related, try disconnecting your ignition so the engine cannot start and then crank it over continously with the throtle wide open, sometimes you can hear the starter 'dog' getting caught on the edge of the starter ring gear indicating that is is not running true.

regards

Dave

 

[Kief]

I didn't notice any cracks when cleaning.. I wish I would have checked for flat on a flywheel or the other flex plate.. I like your suggestion...

 

[Offroads4x4]

Off the top of my head I'd say flex-plate. Was it installed flat? Was it installed back-wards? Was it bent from a bad removal of the engine or from sitting on it before install? Was the 93 an odd ball and has the older trans and they dont match? Is the torque converter a different size? TC installed on angle?

 

[Hokie Fan]

Does the sound go away when you put truck in drive and hit the gas? If so then my bet would be the flex plate. Just had this happen to me on one of my other trucks. Noise was really loud at idle but once the truck was put in gear and i hit the gas then noise was alot less. I took a look and found that a weight had fallen off from the flex plate on the side that was facing the engine block. Put a new flex plate on and all is well now.

Good Luck,
B

 

[Kief]

So... I crawled under there and I definitely used the flex plate with the motor- not the one previously attached to the existing torque converter, can't match up the match marks I made.. DUH. Pulled a bolt to make sure they are the same size (they are) and pried on the flex plate/ring gear and it moved a bit, rotated it and did that a few times...Started it up and I couldn't perceive the noise... Hmmmm. Maybe I just had it tweaked???

Is the FP balanced independently of the torque converter? Why does the manual (not OEM) say to make match marks then?

 

[Kief]

Does the sound go away when you put truck in drive and hit the gas? If so then my bet would be the flex plate. Just had this happen to me on one of my other trucks. Noise was really loud at idle but once the truck was put in gear and i hit the gas then noise was alot less. I took a look and found that a weight had fallen off from the flex plate on the side that was facing the engine block. Put a new flex plate on and all is well now.

Good Luck,
B

No driveshafts attached yet... I'll get there.