Bought the car back in December, it's an 05 Grand Prix GT with about 180,000km (~112k miles) on it now. It's been shifting hard occasionally since Januaryish?
Anyways it usually shifts hard when I'm either stuck in stop and go traffic or it's hot outside. Shifts hard from 1-2, 2-3, not sure about 3-4. Sometimes it slams into first after coming to a complete stop. Transmission fluid is brown, burnt, and has metal shavings.
I was on my way to my dad's friends transmission shop to change the fluid and it started shifting hard and late and the car wasn't warmed up. He scanned the car and came back with a p1811 max adapt long shift between 1-2, apparently the slip was a couple hundred rpm. He looked at the fluid and said if he services it for a flush/change he'll probably make it worse.
He quoted me $1800 for a complete transmission rebuild including GM OE parts, updated parts, and a new torque converter. He said the valves and clutches are probably worn, and the torque converter is probably fine but he'd rather be safe and replace it if he's replacing everything else.
Just wanted your guy's input. Could it just be the EPC Solenoid, or is it worth it to rebuild the transmission?
