missouriman

this has just started the last few weeks.
it happens at most any speed that you are speeding up.
not floored but about like the cruise controll will speed you up when you hold the accel button.
also happens on steep hills 8 percent grade.

oil and filter change on transmission about a year ago, 10,000 miles or so.

truck has 200,000 on it.


thank you for your time.

missouriman

oh, sorry,

it kind of feels like there are chatter bumps in the road.

not as harsh as you find on gravel roads, but simular feeling and timing.

rocket82

I'd say it is hunting for the next gear, trying to shift up but changing its mind. sounds like what mine does at 80 km/h but only that 3rd-4th shift area.

missouriman

it is in all the gears.

guess I will take it to a transmission place and see what they say. I have a friend that works at one.. so it won't be one of those things..

just the folks on here have been dead on with each of my questions so thought that I would ask..
did the search... the search on here still sucks.

thanks again for your advice and time.

SIXSLUG

Try cleaning all your grounds.

missouriman

found it.
the rear pinion bearing had one bad spot on it.
I guess under the right load it would make the drive shaft vibrate.

the really odd part is that the vibe felt the same at low speeds as high speeds.

must have been some sort of a harmonic with the bad bearing and the drive shaft length.