Hi ! I have a 1972 big Block TH400 automatic with a similar problem with the shifter but not the exact problem as you. You could really help me if you could provide me with a detailed description of exactly what you must do when you shift from Park into Drive AND once in Drive, back into Park.

My shifter works quite freely without any binding, sticking and goes into each range you select positively ( it’s detent ) and normally. I have rebuilt the shifter because it had cracked and broken nylon sleeve bushings ( as almost all of them do ). I lubed it with white lithium grease. Still the shifter operates the same. It’s just a real pain getting it to the gear you want. Problem is mostly from Park to Drive and from Drive back into Park.

The 72 Corvette Operator Manual STATES “Press lightly on the shift lever button ( located on top of the handle ) to shift between Neutral and Reverse, or 3 and 2. Depress button fully to shift into or out of Park position. Exercise care in depressing button to prevent unintentional shifts to Park, 1, or Reverse. The floor console is marked 3, 2, and 1 to facilitate manual shifting when desired. “

The real problem IS that you CANNOT just fully depress the handle button UNTIL you have half depressed it to get it from neutral ( and only then ) can you depress the button fully down to get it to go into park. Shifting out of Park the button must be depressed. It will not let you go any further than Reverse UNTIL you let go of the button. Once in Reverse ( and having let go of the button you can then go to Neutral and/or Drive without using the button any more. My shifter has never seemed to work correctly and is a ROYAL PAIN IN THE A?? It almost works like the owner's manual says it is supposed to but it sure is not easy to use at all.

I am almost ready to install a different shifter ( say a 73 or 76 or whatever works more user friendly.

 

Sounds to me like a 'shift cable' problem. It could be the cable, itself; or it could be that the cable retainer device (on the tranny oil pan) is not properly holding the cable so that it operates "firmly". You'd best get underneath the car and watch as someone else operates the shift cable to see what's going on.

 

68-81 AT shifters are all pretty much the same. There may not be a more "user friendly" one.

On both my cars (68 and 80), I fully depress the button to get out of Park and fully depress the button going from Reverse to Drive or vice versa. Fully depress again from any gear for Park.

 

From what you are describing there is not any need for you to have to only half depress the button as the manual states - ever ?

So, You are able to SIMPLY ( while in Park ) Fully depress the handle button and move the handle down into Drive position while holding the button fully depressed in one continous swoop ??

And likewise while in the Drive position, Push the button fully down and in one continous swoop move it into the Park position ?

If this is correct, does it work exactly like this in both your 68 and your 80 ?

 

Here is a pic of the shifter mechanism showing the detents in the gate.
On the right is park. It's a more than 1/2 or full button press to get it out of park. There is no bottom to the slot in the gate that prevents full depression anywhere throughout the gate.
Realistically, you just have to depress the button a little with your thumb and pull back.

Once it's in reverse you don't have to use the button at all, just pull back to neutral first and then further to drive where it will stop unless you depress the button.

From Drive to neutral no button
From Neutral to reverse 1/2 or more button
From reverse to Park, more than 1/2 button.
From Drive to 2, button
OR just fully depress the button anytime.

This all assumes it is synced with the detents in the tranny. Easiest to set when both in Park position.

As mentioned above, your cable is suspect.

If you think the button assembly is partially frozen, unscrew the black ball and the button and squirt oil down the shaft while you depress the shaft, work until free.

 

Thanks for the info. Could you send a pix from the opposite side which shows all the gate pattern. Also what year Corvette is this from ? It is way more simplistic than my 72 for sure. On final question: While in Drive, can you simply push the button fully down, then simply move the shifter forward into Park in one effortless swoop ( without any further effort or interferrence ) ?

I guess I will need to investigate the cable a little further. It sure goes into the correct gear every time ( once you can get the selector there )without wondering where it is.

I would really like to know what other 1972 Corvette automatic owners are experiencing. I hate to buy another shifter only to discover it has the exact problem.

Thanks ALL so far for all the input. It all helps.

 

Correct.

Yes

Yes.

Yes. Also worked the same way when I had my '74.

 

If this car ever experienced a slow cranking that seems from no reason it 'could be a ground is getting bad and the engine is using the shift cable as a ground....a tell tail white corrosion in/on the cable will verify this as gradually affecting the shift cable functions and then finally breaking

 

The pic is from a 75, but they should be the same.
Don't have one of the other side, but there is also a small step from 1st to 2nd.
If you push the button fully down, you can move it from 1st to park easily.
If you disconnect the cable from the shifter, that should tell you if the shifter or cable has the problems. A bad steering interlock cable will give you problems too.

 

Thanks again everyone for all the tips and experiences. I have already disconnected the trans shift cable. The cable moves nice and freely. The cable that is used for the steering interlock has been disabled so their wont be any problem there. The problem lies within the shifter itself. There is not any adjustments on the shifter itself ( other than the neutral safety switch ). The gate system on the 72 shifter is much more complicated than the Pix shows for the one shown in the ( I believe ) 74.

 

Post a pic of the gate.

 

Whats the trick to paste a JPEG photo in the message I want to reply to you ????

 

Here are some pictures of my 72 auto shifter. If I remove the black ( lower ) gate arrangement the shifter works like a normal shifter should. With it installed it is a REAL PITA. Anyone else have this problem ?