4+3 Chattering Problem(Long Explanation)

[86DSOMVERT]

Hey I've been here for a little bit and forgot what I was going to ask all the other "experts" out there.

My 86 4+3 Doug Nash Transmission has/had 69K on the clock. When first started it makes this horrible chattering noise from around the transmission area. You could also feel the shifter vibrating or shaking as it sat in Neutral.

Anyways to make a long story even longer I took it to a supposed "Transmission" expert who drove it all of 25 feet down the driveway of the shop and proclaimed that the transmission needed to be torn apart to correct the chattering noise. So I went ahead and let him do that and he found a bad clutch and pressure plate. Wouldn't you know it the IAC I had just replaced not even a week prior decided to die after I dropped the car off.

Pick it up a week later it won't run, so it has to go on a rollback to the other mechanic to diagnose all these issues.

Anyways fast forward Car Runs again.

Still chatters like mad when cold or this way.

I get in and without putting my foot in on the clutch knock it back into neutral (pull or knock) same thing So now I paid $2,400 for this bozo at the transmission shop who says I'm lying and the car isn't chattering, despite standing right next to the car the day I picked it up and it coming off the lift sounding like it was going into a epleptic(sp?) fit. So now I'm in a battle with this transmission shop and still haven't solved the issue and probably going to go to court.

Reason being is Shop said it was the Transmission, it still makes the same sound that they proclaimed was so dangerous to take on a trip to Bowling Green, yet it made it up through the Smokys and up some 45* mountain grades with no problems.

Symptoms:

Chatters like a bunch of bearings are loose at Start Up (Cold) and through to open loop.

Can cause it to immediately go into seizures AKA Chattering by just pulling the shifter into neutral from say 1st or 2nd.

It will go away and run fine for 100's of miles if just get in it and drive for about 25-30 miles on the open road in OD in 4th Gear.

Overdrive Unit was recently replaced by the previous owner and now I had this transmission supposedly rebuilt

I was reading somewhere can't remember now where but something about Dual Mass flywheels and single mass flywheels. This shop resurfaced the flywheel, but when I mentioned something about DM or SM Flywheel they said NO. Right now cause of spending all that money to solve the chattering problem I'm not on good terms with this shop and I want my money back or at least the portion they proclaimed was for the transmission. I don't mind paying for the clutch replacement it was shot.

Any ideas besides the fact that the car might be possessed.

And I don't know about any of you but I know Doug Nash units are expensive but $2,400.00 for a overhaul to replace 2 parts that I don't know what they were they just pointed to em and said they were bad, yet didn't provide them when I requested them on the invoice and verbally. I think I've been had by another transmission shop.