I have a 1970 cutlass supreme 455 SX that has been sitting for 10 years. When I bought it I was told it had trans problems.
Yesterday I got it running and the car would not move when in gear. I checked fluid and it was on the stick when not running but when I checked it running it wasn't on the stick. I ended up adding 5 quarts.
Once I did that, I started it again and the engine won't rev up when in park It is like I have it in gear and am trying to powerjack the car for a launch by holding down the brake and stepping on the gas.. The engine seems to be dragging down do to the trans. The car still won't move when I put it in gear.
Any Ideas? I am at a loss.
Thanks.
Tim

 

Be carefull trying this, but I wonder if you tried it in neutral position? It may want to pull forward or backward so you must have brakes to try this. Or it could be in 2 gears at once. Look in your shop manual and I'll bet it shows how to check pressures and ports to determine what it is doing before you take it out of the car. Let us know how it goes!

 

Does the car roll? Brake shoes may be seized to drums... it happens over time from sitting still...

 

Sounds like it's in two gears at once like a transbrake. Maybe nothing more than a linkage adjustment or the trans isn't on the correct detent.

 

Don't know why it put the pictures on top?


Thank you all for your ideas and input.
First, please keep in mind that I don't know a lot about auto transmissions

The car rolls fine when not running when I put the shifter out of park (no locked wheels or brakes.)
trans looks like it may have never been worked on. says 62,000 on odometer so I would guess 162,000 on car.

So I went out and did the following:

I started the engine and the engine feels like it is in gear and does not rev up. Like it is in gear but being held back somehow by the transmission.
I pulled it into gear while it was running and the car lurched forward when I put it into R.
I had to shut if off to stop it from rolling
I tried it again . . . same result . . . I threw it into park and it stopped rolling forward.

BTW . . . the brakes do not presently work. Needs a new master cylinder. E brake not hooked up.

So I unhooked the shift down switch on the throttle pedal.
started car . . . same result.

I lifted it up on my lift.
Started the car and put it in gear . . . wheels started spinning in any and all positions of the shift lever besides park.
So it seems what ever I do with the shifter it thinks it is in gear even when in park but the park pin holds it in place.
NO reverse . . . NO neutral.

I also checked the vacuum line from trans and doesn't appear to be sucking fluid out of the trans.
My guesses:
Plugged filter?
Plugged valve body?
Fluid being directed to forward gear due to something not sending fluid to the right place according to trans shifter position?

All input welcome.
Thanks.

 

Drop the pan, all will be revealed.

 

Pressure checks in PRND123. Then drop the pan and look for junk. Sounds like an internal cross leak either in the valve body or farther in on one of the many seals. Disconnect the shift linkage and verify the detents are actually detenting into each gear. It should not move in park or neutral. Unbolt the converter and push it back at the trans and start the car. It should rev without hesitation.
A TH350 or 400 is one of the easiest least expensive transmissions to rebuild.

 

Drop the pan, that’s the first step ( once you have verified its fill of fluid, which you did) if the pan is full of crud safe to say it’s time to pull it out. A line pressure check wouldn’t be a bad idea , if you have access to a oil pressure gauge that will read to 275-300 psi.

 

What I put in Bold font from your post, should be enough to know its time to pull the trans and have it gone through.
......Just my two cents worth.