Ok im on the fence. I have a 40mph bounce, like riding a horse up and down... It seems to be comming from the rear end. It doesnt do it all the time, like when the truck is cold its not there. When it warms up it starts/ Comes and goes but at 40mph.

If i put a trailer on it starts at 30mph. (comming from the rear?)
It does it accelerating cruising and deaccelerating. (not tranny or motor?)
It bounces soft and some times gets rough, when it gets rough the steering wheel will start to shake too.

I had wood in through the rear window, it started shaking befor the cab did.

My tires have been balanced 3 time and i got new rims. they have been rotated and it still feels like its in the rear.

The truck is new to me, came witht he problem. I think it has LS as when i turn real sharp and acc the rear end will chirp chir chirp. fluid is full

U joints all seem tight.

known problems are the rear rotor is shot but was pad slaped and the front ball joints are going.

I really dont want to just throw parts and the search pulls up things i checked, diff fluid level, Tourqe converter, u joints. so im lost but the issue makes my chest bounce and in turn hurts my bad back.

2001 Dodge 2500 5.9 4x4 short bed X cab auto. coil spacer and 315/16 tires. 5 in exhaust

 

I Just went thru this and it was wrong springs, so I see you have a level spacer, measure from the pad on the lower control arm up to the angle bracket on the frame, when I was at 7 inches it would cause excessive wheel hop, (in front) so bad it would shake you off the road, only happened when the drv side wheel would hit a pot hole or railway track and only if going over 50mph (80kph)

measure inbetween where you see the jack

 

mine sitting on the ground there is 7" exactly ad they are stock spings. There is a 2.5in spacer added in there for a lift. I did that to mo old 04 and didnt cause this. let me know and thanks

 

I cant be certain, as I'm not sure what corrected the "bounce" it was either the wrong spring rate springs or the angle of the control arms, you could remove the spacers just for giggles(lots of work) but if the bounce dissappears then for sure its control arm angle,

 

Mine would only bounce (drv side front wheel) if I hit a sharp bump, pot hole or railway tracks and only if going fast (above 45mph)

 

dont know if this will help or not a friend with a standard cab 98 his rear spring pack where it mounts had a crack in it and caused his truck to buck in sorta the same what your describing. he had a lifted truck with a bigger block in the rear front was larger springs. seemed going slow nothing happened as soon as he would pick up speed around 2k rpms or more it would bind buck like a horse how he described it. he said there was almost a full inch of play on the mount between the crack and bushing that had worn down due to this

 

did steering stablizer, checked all tie rods, track bar, weights on drive shafts, changed the diff fluid. and its still there

Im guessing the above post is for the leaf eye-lets? I will check! but

anything else?

 

as posted, my wheel hop is gone, I cannot make it happen no matter what I try! I still believe it was a control arm issue, vs spring rate, now with the lower springs all is good

 

have the same issue with my 04.5, only fom 50-60 mph. just installed new michelins thinking it was a tire issue. no luck. when it's cold it's smooth as glass. always happens when warm. and always with the rear bed shake, then to the seat of the pants. not violent, but irritating. had rear brakes draging/over heating few months back. possible warped rotor? running at 70-80 no problems. pulled rear drive line, joints good. no shake at gear shift or transfer case. 172,000 on a well maintained rig. need help.