Subject: 1971 B Body BB 727 trans, tail shaft spins in the park position.

I removed the shift linkage to eliminate that being the problem. So I have just the shift lever on the trans to select the gears. I also have the rear of the car on jack stands so the axle is free to spin.

While the shift lever is in the "park" position, the tail shaft spins by me spinning the rear tires up off the ground. BTW the starter does engage and spins in the park position.

So before I tear into this not knowing how to solve the problem, is this a simple solution w/o having to remove the trans? Something that can be repaired while trans being still on the car? Or is this an internal problem requiring removal of the trans and tear down?

Any help would help would be greatly appreciated and please ask any more questions if needed to hash out details.

Thanks in advance.

I should add that I do not have any previous experience with this car's running/driving history as it was towed to my house after I bought it.

with the trans side lever in park detent (all the way forward iirc) the driveshaft will still turn? (try & turn a wheel forward and if no sure grip, have only one wheel off the ground & try & turn the other one that is off the ground, forward). Yes that would need the ext housing to come off to access/deal with it.

IMO, drop the pan and see if the park rod is still attached to the valve body lever. If not there should be a dime size circular clip in the pan so beware before just 'dump it'

If its attached , pull the extension hsg and ck the park pawl in the back of the ext hsg case. And condition of the circular cog on the output shaft

my money is on the park rod is off the valve body

I forgot to add when I had both rear tires on the ground I had to use blocks to prevent the car from rolling backwards because it was on a slight slope in my driveway.

As mentioned in my opening post I have no history on the mechanics of this car. I'm trying to determine all aspects of the trans once I knew that it wasn't engaging into park and the starter not engaging when turning the key, such as shift linkage, NSS etc. I have nailed down that the NSS works fine after removing the shift linkage that I suspected that the linkage was binding or sloppy. Plus I wanted to eliminate the linkage being a candidate then work back into it once other problems were solved.

Another reason that I jacked up the car in the rear to get the tires off the ground is I didn't want to have the car start and it having a failed NSS going into gear. I've heard horror stories of cars crashing garage doors, garage back walls etc. So I'm taking extra safety measures when deciphering this problem.

Anyway thanks for the tip and I will give it a try.

Thanks for those tips. If any of these symptoms are the problem I'm hoping for the the park rod on the valve body.

Going off of your reply, I wanted to ask some more questions if you don't mind.

Does it matter when shifting the side lever into the other gears (R,N,D,2,1) if the park rod at the valve body is the issue? Does it effect the shifting transitions? So basically just having all the gears engage and having the issue with the park lock?

Not that I would drive a car around knowing that the park won't engage but I just wanted to know all angles for future reference.

I will look into your advice since I can inspect it while trans is still in car.

Thanks for your help.

The park actuating rod on the valve body has to go through the back of the tranny case into the tail shaft housing to engage the park gear on the output shaft, they are easy to install incorrectly That park rod has a spring on the lever on the valve body end to allow for slop and for the linkage in the tail shaft housing to move if the lever and gear are not aligned correctly to engage them at first, in that case the car may moved forward or back wards a tiny bit when you let off the foot brake Another part in the tail shaft area that could be broken is the spring on the engagement lever mounted onto the main case
As far as the starter not turning the motor over their could be several different non related issues such as the Bendix on the starter being broken, the torque converter bolts not installed into the flex plate and probably several other things that are not coming to me right now
Good luck, let us know what you find out that fixes both