I hear (and feel) a brief vibration whenever I am cruising along and try to accelerate. The noise and feel is like running over the “slow down” bumps as you approach a stop sign. I don’t have any problem accelerating and there doesn’t seem to be any other issues.
Any help would be appreciated.
You didn’t mention the type of transmission that your truck has, but if it has an automatic transmission, my prime suspect would be a problem with the torque converter lockup mechanism.
The solution might involve merely servicing the transmission, especially if the fluid and filter haven’t been changed every 30k miles or so, or it may require replacement of the electronic module that activates/deactivates the torque converter lockup mechanism, but–either way–I think that a visit to a well-reputed transmission shop should be your next step.
Ask friends, relatives, neighbors, and co-workers for the names of good independent trans shops in your area. Whatever you do, do NOT go to Lee Myles, Cottman, Mr. Transmission, or–God forbid–AAMCO, unless you want to be overcharged for substandard workmanship.
Is it in 4wd when this happens?
Another idea, sometimes a two-part driveshaft will do this if the splines where the two parts meet up need to be lubed.