first question (2000 SL1)
 

it may or not be a problem... but the car drops out of O/D going downhill(actually downshifting if you brake) and sometimes doesn't want to go back in after reaching the bottom of the hill, even after accelerating to 50+ mph... it always eventually goes back into O/D though...

i read that the car was built after they made the transmission ("read driver input patterns", or some stuff)... is this sort of behavior normal? drives great otherwise, just not used to the tranny acting like it does...

bump, is the above mentioned behavior normal for a late model Saturn with the auto gearbox? you know, after they got rid of the economy/sport button...

I'd swing by a "Saturn friendly" dealership, and have them check the transmission computer for error codes ( or anywhere else, for that matter)

a code reader didn't show anything... but i don't know of a "saturn friendly" dealer near me...

sorry no help from here my s cars are all 5 speeds

That is usually a function of cruise control, but to act the way you describe, it would be a cruise control gone amuk.

Call GM customer service, they know all Saturn friendly dealers

When I had the automatic in my car it was a very, very funky little transmission. It would downshift under braking at times, but when I made it downshift on the highway to go faster, the revs would jump high then slam down into gear, as if the torque converter was letting loose. Mine was also missing the econobox/performance mode switch. So i think it was trying to econobox me all the time

I remember reading somewhere these transmissions learn how you drive, seeing that its your wifes car maybe your driving it abit differently? I remember when I lent my brother the car it would shift early for a few miles, cause hes slow hahaha

Well ... now that I think about it, I did have some problems with the automatic tranny in our '98SL2. Would be driving down the road (level road) in cruise control mode, but could feel the transmission going in and out of "O/D". The tach would mirror the problem with a 600rpm jump/drop as this occurred.

Finally got the dealership to connect a set of gauges to the transmission, and take a ride. Fortunately, the car was cooperative, and misbehaved for the tech. Final decision was that the final control valve for the "O/D" was not locking up properly.

At the time, we were still under warranty, so the dealer simply dropped another transmission into the car, and away we went. Don't know what it would take to repair such a problem ...

from what you said I would guess valvebody rebuild, next best thing to do before dropping it