Hello,

1999 Mercury Grand Marquis LS
117,000 Miles

My Problem

While driving at a steady speed mostly low speeds 55 and below sometimes higher speeds. My trans feels like a jack hammer when I just slightly hold my foot on the gas pedal. Only way to make it stop is to let off the gas or give it more. Trans does shift fine though and when not acting like a jack hammer its a very smooth ride.

Things I've Replaced

Trans solenoid (both of them)
Speed sensor
fluid/filter
Throttle position sensor

Any ideas would be very much appreciated

 

You were looking in the right area when you swapped the trans solenoids, but unfortunately that did not solve your issue.

It maybe scan tool time to see if your CVI is not getting pressures, etc. If your CVI shows high wear and your soleniod pressures are weak it maybe trans rebuild time.

Sorry I could not be of more help here. Let us know who you make out, Bill