2007 suburban 2500

[JandJsuburban]

P001 issue that never goes away. I bought it from a fellow that has changed almost everything to do with this code. He's taken it to some of the best techs in New England and no one has yet figured it out. It runs beautiful until you start getting rough shifts. It's fine right after an oil change. Good for 2,000 miles or so. Mobil 1 synthetic. Then you start getting rough shifts. Especially 1-2. The light eventually comes on . You clear it and then she is fine for a while. Then it seems it only acts up as the engine gets warm and things loosen up. When it's cold she runs amazing. There is a rinsing issue between the motor and tranny that is making this thing act whacked. Oil pressure cruises warm at about 38 psi and warm idle 22psi. It's really not the end of the world. It drives 95% of the time beautifully. I bought the vehicle fully knowing this suburban had this issue. It only has 103,000 on it and is absolutely beautiful. It has had a new tranny put in it because the torque converter went and the previous owner figured he'd change over everything. Any help or thoughts would be awesome.

[newdude]

Do you have any trouble codes present?

[JandJsuburban]

Edit.... timing issue between motor and tranny.

[JandJsuburban]

No. Check engine light will come on and throw p0011. I'll clear it and it stays off. I'll still get intermittent bad shifts here and there though.

[JandJsuburban]

I've owned it for a couple weeks now and it came on only once. Shifting is periodic. But seems to happen only when it's nice and warm. The only other thing I've noticed. When I get a rough shift it takes a couple miles for it to shift smooth again then stays good. But on top of that, when I get a rough shift and if I put the selector to auto it will revert to 4 wheel hi. It stays in two wheel drive when things are shifting fine. Not sure if there is a connection but I'm trying to think outside the box.