8l90

[vet57air]

So truck has been sleeping all winter and took it out a couple of days ago. Drove fine until I gave it significant gas and it rev'd then not several times. Came home and has check engine light on PO700 which is a transmission code and P18C2 pending. Also am told shifter positions are PRNDM. Mine and at least 2 others have one more detent, PRNDM? Heard it could be PRNDML?

[srode1]

Have you called GM or talked with a GM performance dealer about it?

[vet57air]

Originally Posted by srode1

Have you called GM or talked with a GM performance dealer about it?

I chatted with a GM performance tech today. Says delete codes and see what happens. I asked about the extra shifter detent (2 of my buddies have same) and all I could get from him was don't use it.

[vet57air]

So I removed the battery power and then powered backup. Problem remains. Works fine in drive but when I shift to manual the shifter indication does not change, still shows its in drive. It does go down a gear and stays there but cannot manually shift.

[vet57air]

Have an appointment with a GM dealer. Called GM tech line again to ask for a answer on the extra shift detent, no answer yet. Also asked for warranty as I have just 600 miles on it but just over the 2 years. It is always tough building a vehicle under 2 years as you generally buy your drivetrain to fit first and then build the rest. My buddies that bought the same engine and trans packages about the same time I did do not have their projects completed yet. But they both have the extra shifter position that I have.

[vet57air]

Had my appointment with a Pacific GM dealer today. They treated me very well. Spent a couple hours testing to checkout the P18C2 code which is "internal mode switch". Next step is taking the pan off so we have ordered a mode switch in case that ends up being the problem. Still have not heard back from GM on warranty or extra shift detent.

[vet57air]

I finally got a email from GM telling me there are 5 detents used and 6th is not. Not really any help as I and 2 others I know of have 6 detents. When shifted from M to the 6th detent I get "error" displayed.