I have a 2001 supercrew with the 5.4 v8. When I accelerate up to fourth gear, I get some vibration throughout the vehicle. This only happens in fourth gear. My vehicle has 100k and I just had the transmission replaced 10,000 miles ago. The check engine light has not come on. I am guessing this could be a transmission issue. Does anybody know what this could be? Thanks

 

Lots of things, from bent drive shaft to bad u-joints to bad trans mount and about a hundred other things. Could even be a bad balance on your tires.

 

Vibration in 4th gear? You mean in Overdrive? Your auto is a 3 speed + overdrive. If you're "accelerating" into "4th" gear, then you've got to be going close to 100 mph. At that speed in these trucks, it could be a bajillion different things causing the vibration.

 

Sometimes a coil pack can go bad and cause a miss. It can feel just like the tranny jerking. The check engine light also does not always come on.

 

If the overdrive light is flashing, its bound to be trans related, you need to address teh cel first, and go from there....

 

I agree with Wandell, your problem might be a coil pack or two. I just had my first experience with this problem. In April, I went Sturgeon fishing in the Columbia River near Portland, Oregon and on the way I noticed at 75 mph the slightest interruption in the cruise control and the smooth constant speed. It has progressively gotten worse to the point that I wondered if it could be something in the transmission, the fuel filter, coil packs, or engine disaster. The 'check engine warning light' only came on last week when it was the worst, the vehicle literally shook at slow speeds, missed at all speeds, and at idle. I even thought that it might be bad gas. But it was a coil pack, my truck runs as if it were new now. Check the easy fix things first, you might be surprised. The dealer knew what it was in an instant and fixed it for $231 and from a dealership that is not bad. Merton Leeper