strange noise and feel while accelerating

[jw1987]

I have a 2000 Expedition 4.6 with a difficult problem. I have had it to 2 Ford Dealers, 1 Goodyear Automotive, and 2 local mechanic shops. None of them could diagnose the problem within the full day that I left it with them. I will try to discribe the problem the best I can. I am hoping someone out there has experienced something similar and found a solution...

basically, when I accelerate quickly from a stop, or when going from 55 to 70 or so on the highway, I feel a rough vibration under the gas pedal and I hear a sort of "gargling" sound. And when it finally shifts into gear so I can settle in and cruise at a desired speed, it sort of clunks firmly into gear. So firmly that it even pulls the wheel a little. I also noticed that when I use cruise control and am going up a hill or grade on the highway, the car will suddenly "floor-it!" sort of...going up to 5 or 6K rpms instanly until it gets back up to the cruise speed setting. I have been in lots of cars with cruise control and never exerienced this.....not sure if it is related to the main problem I am experiencing or not.

One of the mechanic shops recommended that I completely flush my transmission fluid. I read the marketing display he has for this service, and it seemed to describe what I was experiencing (irratic shifting, etc). So I had that done a couple of months ago and it has not seemed to have any affect.

This problem has been going on for about 6 months and does not seem to be growing worse over time, although I just took it on a 18 hour round trip and the problem seemed much more noticable during all that highway time.

Thanks for reading all this. I hope to hear from someone with some suggestions.

-jw

 

[DodgeRamAw06]

I had a similar problem a few months ago. My truck would jump to 5k rpms just to get back up to speed when the cruise was on. My local shop sold me a b&m shift improver. Its an elctronic device that taps into the computer. It was a little difficult to put in but it is possible. i was told the shift improver is to firm up the shifts by raising the pressure in the transmission line. i hooked the box up and it worked out great. The box really tightened up the shift and it fixed my rpm problem. The shift improver isnt ment to fix the problem i had but it did. B&M Electonic shift improver is the name of it, just 35 dollars. Hope this helps
Dustin

 

[Truckgirl02]

I have a similar issue with ours. When you are accelerating normally, there is a sound like some splines aren't aligning correctly and it happens around 45 mph. If you get on it a little bit it happens around 50 something. Any hints as to what this is? I don't have the acceleration issue, and the trans shift very smoothly, motor runs great, just have this short growl sound in the last gear that is a little concerning.