i have a 99 ram 1500 5.9L automatic everything was great with the truck, then the trans went, i replaced the trans and ever since that day (a month ago) i have a nasty driveline shake. it starts around 25mph and goes on. it doesnt shake the truck at all, its def in the driveline somewhere, like the transfer case or rear shaft. at higher speeds my 4 wheel drive shifter goes nuts. it ONLY shakes when i am on the throttle. the second i get off the throttle at any speed......its smooth as can be again. and if i put it into neutral at any speed and rev it up....its smooth. its only when the driveshaft is under torque. the truck is an extended cab reg box. and it is lifted roughly 4 inches and on 35's. But this problem i doubt is lift related bc it was fine for months lifted. ??? U joint maybe ???

 

did the vibration start immediately with the new transmission. if so, where'd this transmission come from ? and do you have a warranty ?

also check the drive shaft u-joints. wheels blocked, trans in neutral, brake off, no tension on driveline - try to wiggle the u-joints. should be zero play. check that the seals around the needle bearings are intact and tight.

check the driveshaft for the original balance weights being present. make sure they didn't fall off. also make sure driveshaft is bolted up to the rear end yoke properly.

if nothing is obvious, put the rear end up on jack stands. have an assistant run the truck in gear while you get under it and look/listen/feel. be very careful doing this - a lot of bad things can happen to your hands, arms, hair, clothes, etc.

 

yes it started immd, i noticed it on my firrst test drive with the new trans. i got the trans from a donor truck, i ran the trans in the donor truck and it was perfect, came from another truck with only 60,000 on it. i dont think the problem is in the trans.

there is slight slight play in the rear front U joint by slip yoke. and ther rear rear U joint is tight. Do you think i can be getting this much vibration from a bad U joint? i replaced the rear rear U joint last year and when it was on its way out the only thing that one did was click at lower speeds under torque. didnt vibrate really at all.
thanks for helpin i appreciate it

 

Did you torque the bolts on the transmission mount good?

 

matter of fact the mount was shot, and i thought thats why it was vibrating so bad so i replaced it just last week......didnt solve anything....everyhting there is tight