V-6 Engine Rumble

122,000 Miles: While foot on brake in drive or reverse and at 1200 RPM the truck rumbles through the seat and while on the road at 40-40 MPH the car feels like it is on a roughly paved road when actually on smooth payment. Ordered a Transmission Mount thinking that may be the fix. I don't believe the engine mounts at this low mileage would need replaced at this time.
Any thoughts would be greatly appreciated.

 

Interesting issue similar to a problem I solved!
Try driving in S4 instead of " D" at slow speed/light throttle -say around 25-35 mph.
Then see if "rumble" went away. Then put in "D" and repeat test and see if "rumble" returns.
Post results as I have lots of info -if S4 makes "rumble" stop!

 

I'll do that.
Thanks for the suggestion.
By body mounts you mean cab mount to the frame under the driver seat............?

 

Driveshaft carrier bearing sounds like it needs to be replaced...and/or greased!

 

Search “rumble strip issue.” Sounds like a possibility.