ok so when i went and took my truck for a 5 hour drive to bangor maine i noticed at 65mph it would almost (misfire or die out or clunk or something!) then it went away when i got home. well today it was clunking from the tranny/crossmember or radius arm bushing area. not like a clunk i mean a CLUNK! to the point where it sounds REALLY bad. and i have a random misfire or quick dieout. lasts no more then 1/2 a second and goes normal. tomorrow im going to recheck my crossmember bolts to make sure they are tight from when i put the tranny back in since i welded the case back together. im also going to check the tranny to engine bolts and the tranny mount bolts as well. im thinking it maybe my radius arm bushings too. because sometimes when i come to a stop i get down to about 5 mph and i hear a clunk right before i stop. i know its not a braking issue but i think it maybe something with the bushings in the radius arm causing that. any thoughts? or suggestions?

Wait a minute... Sounds like there multiple issues here. You say you feel like the clunk is in the crossmember or the radius arms then how would it make you engine feel like it's going to die?

What I was GOING to say... There's a TSB that Ford put out about the transmission crossmember on these trucks. They can build up stress in the crossmember and sometimes under stress it will 'give' a little bit, which reverberate a loud clunk throughout the chassis. The TSB says to just loosen all the trans crossmember bolts, then jack the rear end of the trans up just a couple FRACTIONS of an inch, then drop it back down and tighten everything back down. This will relieve any stress that has built up. If you want the TSB gimme your email and I can email it to you (pdf format).

Other than that, it sounds like you already know that radius arm bushings can cause clunks too so that might also be your issue.

Neither of these problems should cause the engine to malfunction so I'm not sure about that portion of your problem...

I remember reading about that TSB , solved alot of peoples problems.

i know about that tsb. i do have 2 issues that started around the same time ironically. they are not linked just happened at the same time. im concentrating on the loud clunking for now because it sounds worse then the random "skip"