on my truck, when im driving and let off the gas, it kinda feels like it.....hard to explain. it kinda kicks and seems to bog down a good bit. when i put my foot back on the gas, it clunks and goes. i'll check out the u/j. are they hard to replace? its been doing this since i got the truck. its had me worried figureing it was the tranny since ive had so much bad luck with them. also, where can i find said u/j in the event of replacement?