I have a 1999 Pontiac Transport Montana. Normally I only drive this car
fairly short distances (under 25 miles), however recently I've had to do
some longer commutes, and have noticed a problem.
After the van has been driven about an hour at highway speeds and then into
city drivng, the transmission will shift VERY "sharply" between gears. This
never happens if the van is driven shorter distances, only if it's been run
on the highway for an hour of more. Once the van cools down the problem goes
I tried having a additional trans cooler installed, and this hasn't had made
any difference. Is this a sign the trans is "done", or is it a fluid or some
Again, it's a 99 pontiac trans sport, 3.4l engine, and has about 110,000
miles on it. The trans was replaced under factory warranty at about 30,000km
due to a defect, so the trans has roughly 80k on it.
Thanks for any insight!