03 F350 vibration after shift into 3rd
Well My truck has a vibration after it shifts into 3rd gear. 1st and 2nd are smooth, shifts into 3rd and the truck feels like has a bad tire. Then continues this in all the final gears. Does not slip. At the same time this began if youre cruising at hwy speeds and under a load its smooth but once you sligtly let off the throttle it has a bad rubbing/grinding type noise, get back into it and it goes away.
I pulled the trans pan and the fluid is red and doesnt smell burnt. The magnet has crap on it but what Id consider normal crud on it, no large metal pieces. Truck has 148,000 miles on it. Please Help!