I know this is a tranny question but I figured I would get quicker help here. So, if it must be moved to tranny then feel free to do so. I'm trying to figure out a sound in/around the tranny while in park (see my post in the 4L80tranny section). I am currently checking to make sure the torque converter bolts are tight to flex plate. I read that you should be able to rotate the flex plate with a screw driver. Is this true, cause I cant budge mine an fraction of an inch. Nor does the converter rotate by hand. IS something binding in there maybe? Could this be why I've been seeing higher EGTs? I have found that if I can get my screwdriver into some brackets on the converter and really force it I can get it to rotate.

IS something binding in there maybe?

Yes, here's a pic of what's binding :):

80749

You'd probably have to pull the glow plugs (no more compression) to turn it over with a screw driver. There are generic flywheel/flex plate wrenches available, which will give you alot more leverage:
http://www.jegs.com/p/JEGS/751072/10002/-1?s_kwcid=flywheel%2520tool%7c2620806530
If those bolts ARE loose, it will make quite a racket & destroy a flex plate in no time -and likely some other, more expensive items too.

actually jamie, that engine WILL turn by hand with a screw driver without the glows removed....i've done it countless times.

its a PITA but not as much as removing the glows to do it

So I wonder if/what could be locked up? That sound... only similar sound I've heard come out of a transmission is putting it in park while still moving, weird how it only does it after backing up in 4wd, I kind of wonder if that little clip that goes inside the back of transfer case could be broke, I've only limited transmission experience.

Because it only does it after reversing in 4wd, that makes me think there is some kind of issue with movement of a shaft forward and backward; maybe some kind of thrust plate is worn out inside. Someone give him a real fix, I'm just saying what I think could cause it.

hmmm sounds like somethings broke free inside either the t-case or the transmission....unfortunately i don't have much experience with the 4L80-E myself...i'm a 700R4 guy and even then i'm weak on that subject

I dropped the pan and found no metal pieces. I'm leaning to a torque converter issue here??? I did manage to turn the flexplate over with a screwdriver even with the glows inplace.

sine it happens specifically after 4X4 is used....(iirc) i would lean towards transfer case not transmission...if you want to test that, i think if you put the transfer case in neutral and transmission in drive....? we really need a tranny tech for this question