2002 Dodge Ram I got new tires this year and replaced rack and pinion and tie rods. First thing in the morning when truck is cold I get on the highway and truck feels like it is bouncing in the rear almost like it is riding on flat spotted tires. After I get out of work and drive home it still does it but not as bad when truck is first driven in the morning. I have read some where else possibly c v axles being worn I was thinking rear end but not sure. I don't think its the tires because I think it would be the same bounce every time I drive it. Anybody else have or had this issue or any ideas what to look at. I didn't have the bouncing after I put on tires at beginning of the year only started a few months ago. Thanks

 

What kind of tires? Bias ply tires develop flat spots when it gets cold out really bad. I say you should start by checking your air pressure in them bouncy black doughnuts. If it goes away after a short drive then most likely it is not a tire out of balance. However it keeps on bouncy, bouncy then it might be a combo of low pressure, bad balance, or worn out shocks, or cold bias ply tires.. good luck.

 

Will check tire pressure. I have Toyo AT3 got them at the beginning of the year. I talk to my buddy who works for Chrysler and he said check u joints for rust. Also I ordered new rear shock yesterday so I will see what happens. I did soak u joints with wd last night and didn't feel it this morning on the way to work but not crossing my fingers.

 

While your at it with the u joints. Check to make sure your drive shaft is straight.

 

Common problem. See here -> https://dodgeforum.com/forum/3049574-post5.html