"Virgil W. Depew" wrote: ( 1994 Ford F150 conversion van )
Sometimes when driving at 75 mph my transmission seems to jump
out of gear and immediately go back into gear, sometimes hard and
other times barely noticeable.
It does not make a difference what speed I am going, whether in or
out of overdrive, and whether cruise control is on or off. I have
changed fluid and filter with no improvement.
My Ford dealer said the transmission is okay. Any suggestions?
Many transmissions have an extra clutch in the torque converter
which locks the engine to the transmission at cruising speed and
which unlocks to let the torque converter slip during acceleration
or low-speed operation. The clutch is engaged electrically, when
the engine control computer senses the proper conditions.
When the converter unlocks unexpectedly it feels like it downshifted
but it hasn't. The engine just revs up until the converter slips
enough to match the throttle pressure. And when the converter
locks unexpectedly it feels like it went into a higher gear, but it
hasn't. It just slows the engine until converter slippage is gone.
The problem could be in the computer, a lockup relay, the converter
clutch, or just a bad electrical connection. Check all connections
before trying any servicing.
There may be other problems here. If, as you say, it actually jumps
out of gear, something else is wrong. And it is odd that it happens
at all speeds. The converter clutch is never supposed to engage at