2000 Pontiac Grand Prix 4T65e No 1st gear

It's been a while since I've been here. Busy times. Hope you're all well

Anyway, personal car is a 2000 grand prix GTP with the supercharged 3800 and 4T65E. 250,000 miles on the clock.

Transmission stays in neutral with gear selector in D, 3, or 1. Shifts into gear with selector in 2 and will make forward motion. I didn't drive it any further. Scan tool shows the correct PRND321 positions. Scan tool appears to show desired gear, not actual gear because shifting to D 3 2 or 1 shows gear as 1 and doesn't indicate the neutral condition or show 2nd gear from a stop.

I'm at a loss for where to start. I would think valve or solenoid but going into gear with shifter in 2 is strange. First question would be would solenoids fire differently from a stop with selector in manual 1 or 2.

I'll look a little closer on Saturday and get a test drive to see if any other symptoms.

Many thanks

PDM! Good to see you!

My understanding of the 4T65-E transmission is that it should default to 3rd and Reverse with the transmission connector unplugged. I'd try that first. If you still don't have 3rd or Reverse, then either the PRNDL switch is lying to you, or there's internal problems in the transmission.

You can also disconnect the shift cable from the transmission and move the lever by hand (with a helper behind the wheel and their foot on the brake, of course). If you physically move the lever from P to D and it shifts fine, then there's a switch or cable problem.

I don't have a helper today, so I didn't pull the shift cable.
I forgot to mention, no codes.

With the harness unplugged, it defaults to R and 2nd.

Reverse has good torque. No converter issues.
D and 3 have no forward drive and I can't feel it shift out of neutral into 1st gear.
Manual 1 and 2 I can feel shift out of neutral into 1st but severe slip in 1st gear. Once the car is rolling, it will shift to 2nd when I let off the accelerator.
Manual 1 and 2 applies an additional band. This is why 1st doesn't apply in D or 3.

It won't make a shift in any gear with heavy throttle. Engine just free revs.

Smells like either pressure control solenoid or issues with the forward drum or piston.

Now to decide if this car is worth my trouble.

With the harness unplugged, it defaults to R and 2nd.

Reverse has good torque. No converter issues.
D and 3 have no forward drive and I can't feel it shift out of neutral into 1st gear.

Ah hell. I was hoping for an electrical problem.

Any chance of finding a decent low mileage used trans around your area?