Auto Transaxle Advice - '99 GA SE V6

I'm getting conflicting opinions on a transmission problem with my 1999 GA (130k miles). When it is in overdrive at highway speeds, it seems to have trouble "deciding" whether to come out of OD when a little extra power is needed to climb a slight hill, for example. I have one opinion that says it's likely a computer problem that may be fixable through a flash at the dealer. I have another opinion from a mechanic I trust and who would lose money on the deal if I take his advice that says trade it in while I can still get something for it b/c the transmission is on its way out--a computer problem would affect all gears at all speeds. Has anyone had a similar experience? If so, how did it turn out? Does anyone know of a reputable transmission shop or GM service dept. in the Baltimore/Washington area that will give me an honest opinion and estimate on this? I don't want to dump a car that needed a simple CPU flash. On the other hand, I don't want to be stuck with a bad transmission and a vehicle that's only worth parts.

Take the car to a transmission shop and have it diagnosed. This sounds like a sticking torque convertor lock-up solenoid. They will go bad and produce the problems you indicated. A trans capable scanner will pick this up very quickly. Cottman Transmissions or AAMCO can scan it for you and let you know what is wrong. It will cost a few hundred to repair and I think your car is worth more than that.

I agree with GTP Dad.

Take it somewhere to get the trany scanned.

Thanks for all of this info. A few hundred is definitely worth it. I will take it to get it scanned and hope for the best.