I think my transmission is gone
 

Just wanted to check, but I'm pretty sure the transmission in my Buick is history.

Drove it on a long trip today, drove great the whole way down. Then when I got there, it stopped shifting out of first gear right...it waited until 25 mph to shift, and then when it did, it "let go" and revved up before shifting to second...pretty sure that's slip. Also, the torque converter and fourth gear now come together at 30 mph, and with a pretty bad vibration.

We made it back, but on the way there I kept getting P0753 check engine code...

Trans level is full and pink. Trans temps were right around 150 degrees.

What do you think guys? Is my transmission history?
.
.
.

P0753 is a electrical code, so I don't believe the trans is gone. That's the 1-2 shift solenoid. I suspect it went out. Do you have any other codes? Do you have a DVOM, digital volt ohm meter? If so we can test a few things. The only problem is, you will need to remove the transmission to change the solenoid.

You can remove the solenoid by removing the side cover, but it is a very involved process.

Wont he need to lower the transmission to get the side cover off? There's not a lot of room with the brake lines there.

You are correct. The cradle needs to be lowered, but the trans can stay in the vehicle.

Ah, thanks for the tips guys. Good to know my trans isn't totally dead anyway. I don't have any kind of tools along the lines you mentioned, but a failed shift solenoid would explain it's weird 1-2 behavior.

I'll have to give this some thought. What a pain though!
.
.
.

I would be interested in seeing how that is done. I know when I dropped mine I split the sub frame and remove the drivers side. But it was still a tight fit past the brake lines.

Do you think it would be worth throwing in some SeaFoam trans tune in to see if it frees up the solenoid?
.
.
.

I don't believe that will do it, but will see what Steve has to say.

If you have a solenoid electrical code, the solenoid has "failed" electrically or has come disconnected or has a computer problem, so I don't feel that ANY additive in this situation will be at all helpful.

Don't forget that when we remove a side cover, the car is on the lift and yes, it can be a little tight. But it is a lot easier to remove the side cover than to remove the whole trans.