'96 XJ "Shuddering" Problem

[JMAN3203]

From what I've gathered searching so far, it's either:

A)Torque convertor or B)Misfire

I've been driving my dad's Jeep XJ with the 4.0L, AW4, NP231, and when it shifts into OD it starts to shudder, pretty bad I think, from ~ 45-55MPH. It happens only in OD and that MPH range. If I keep it in 3rd past that, no shudder. It always downshifts into 3rd when letting off the gas, no matter how fast; (I fucking hate automatics!) So I guess you can say it's only on acceleration.

My dad overheated it when a plastic heater line piece blew and he overheated it pretty bad, mom asked him what the knocking was. Then I came close to overheating it when the upper rad hose at the pump commited suicide, LUCKILY I was at an ATM when I noticed the electric fan kick on and thought WTF? Popped the hood and a puddle of coolant, lost about a gallon.

Back on track, whenever my dad overheated it the CEL came on, and I forgot what PXXXX codes it was but it was misfire #1 and random multiple cylinder misfire or something. I know what you're saying, "Well there you go you fawking 'tard!, misfire right there!" I always like a 2nd opinion and am not going to rule out the tranny but am really hoping I can. Hell I think he even had it rebuilt not to long ago. (Not certain) Tranny fluid is still pink and unburnt. It just seemed worse today, :shrug:.

I'll ask again come Tuesday if no ideas .