2005 Ram 1500 QC (all stock)

I have noticed that at speeds starting around ~70mph to around 75/80mph. My truck will bounce, its not really a side to side rattle but an up-down motion with some stuttering(As if you were driving on a bumpy road). I do not have this issue at any other speeds, it does appear to be happening at high RPM when the truck should be shifting. I haven't flushed the transmission yet, 70k Miles. I was told it was done once around 40k.

Any advice? I'm going to be doing a lot more highway driving pretty soon so I want to get this worked out!

Thanks!

 

bump, looks like i got buried. Anyone have any insight?

 

I think that tires out of balance can cause vibrations more noticeable at certain speeds. Well either tires or driveshafts. The stuttering that you mentioned, do you mean the engine is running rough or the tranny is running rough?

 

My limited knowledge aside, I would say it seems like the tranny. It just strikes me odd to only happen under very specific circumstances. I might check the tires, but I have had them rotated and balanced recently but do not recall if it started after that. And it isnt so much vibration as it is a up and down bouncing. Is this something i could take somewhere and have it checked? Since it has be going like 70mph to recreate.