Was backing the Cutlass out the shop last night, so I could put a truck on the lift, and it stopped pulling. No extraordinary noises. Trans won’t engage any gear and will also roll in park.

Anyone want to guess before I pull it apart?

 

Linkage

 

Can you feel the detents as you move the shifter Park to Low and back?

 

This. Jack the car up, disconnect the linkage from the trans lever, and see if you can rotate the lever on the trans into each gear. If you can get it into park that way, the problem isn't inside the trans.

 

I did briefly glance under and make sure linkage is still hooked up last night. It is.

The troubling part for me is how it just quit pulling. Engine doesn’t change pitch now at any detent. Something is still moving inside the trans though, when you go to park you get the grrrrrr sound like if you accidentally shifted to park while still rolling.

 

I bet your going to find the nut that holds the rooster comb to the manual shaft loose. The rooster comb can wiggle enough that the S shaped link can fall out of the manual valve. Since the linkage to the park rod would still be connected to the rooster comb, it will go into park.

Don’t pull the transmission, you can easily fix this by removing the transmission pan.

 

I bought a 66 Cutlass yesterday with the same issue. It has a Turbo 350 tranny as well. I'm curious to see what you figure out.

 

I literally just got off the phone with a buddy who said the same thing.

Didn’t get to mess with it tonight, getting ready for big race. Will pull pan and report findings tomorrow.

 

Basics first:
Fluid level?
Take pressure readings before you disassemble anything.
Then drop the pan.

 

Was about to write the same thing.

Had a 85 Cutlass sitting for a few years. Car started but had no gears whatsoever. Enough transmission fluid leaked out that shifting it was as if it had no transmission attached to the shifter. Added fluid and it was like magic, instantly 100% working condition again.

I'm thinking this may apply more to you Chris than Jhucks, as you just bought it and maybe its been sitting a while ? But both of you should check just in case. It cost nothing and you can address or rule out simplest potential issue. Then work your way from there, next simplest step at a time.

 

Pulled pan down, linkage still attached. Fluid level was fine and good and red.

 

You didn't follow the order I suggested.
The best way to troubleshoot a hydraulic pump (automatic trans) is to take its blood pressure in all 6 gear selector positions.

Each position has a min/max pressure specification. If the pressure is above or below the spec it will point you in the direction of which hydraulic circuit within is failing.

There's a strong possibility the pump has failed or something is leaking (internally bypassing).
I think the trans is coming out for a rebuild...but verify the pressures first before going directly to trans removal.

You need a good trans psi gauge rated for 300+ psi.

 

I have to agree. Either get a pressure gauge, or disconnect the cooler lines. Have a helper sitting in the drivers seat, start the engine, and be ready to shut down the engine quick. No fluid from the cooler, no pressure. Most likely the pump broke.