Dman03GT

Hey guys... I have an older style 4L80E that was originally behind an older SBC 350 bolted up to my LQ9 and noticed some flexplate wobble after feeling some vibration at idle and low speed. I got under it today and set up a little rig with vice grips and a caliper and measured the runout which turned out to be .044-.046"

Is this a normal amount of play or excessive?

Heads-Up-Outlaw

That does seem excessive.

I would recommend unbolting the converter from the flexplate, shove it back and then run the motor to see if the vibration is still evident. Also, while it's unbolted check to see that the converter hub is not interfering with the crankshaft. It should rotate very freely when it's up against the flexplate and not bolted up.

And of course the flexplate could simply be warped too!

Dman03GT

I'll check that tomorrow, I was planning on unbolting the converter and checking to make sure it didn't need to be shimmed anyways and will see if has any play w/o the converter. The flexplate was brand new so I'd be pretty upset if it came in warped.

Heads-Up-Outlaw

Cool. Glad to hear you are running a new flexplate. I doubt that's the source of your vibration.... Ten bucks says the converter is the source of the vibration. I don't recognize it. Who built it?

Dman03GT

As far as I know it's a factory converter, came with the 4L80E out of a 94 1ton van. Plan to be upgrading soon, but I needed to get the project moving on its own power.

Dman03GT

Well solved the issue today, I unbolted the converter turned it around and shimmed it an all is good now.