06 GTP Auto... "slips" in Drive, but sport-shift works fine?
The problem is more or less as the title states, not sure I could describe it much more.
My younger brother has a 2006 G6 GTP, and he was just about to sell it, then this problem came up, so I'm doing whatever I can to help him out.
I took it for a drive the other day, and when in Drive, the car just seems like it's slipping, as though it's in between Neutral and Drive. If you put it over to the "sport shift" or whatever you want to call it, it drives fine. No slipping, no hard shifts, nothing weird.
The fact that it drives fine when "manually" shifting it makes me think it's either electrical or something valve related in the transmission.
The place he bought the car told him straight up that he needs a new transmission and they can't find one, and they're trying to offer him next to nothing on a trade in. I'm going to call BS on that at least.
I did a search here first and found some kind of similar problems, but nothing exactly the same. Surely somebody has had this issue before and has an idea.
Any help is greatly appreciated.