HI, looking for some help on adjusting the back drive linkage on my 1972 cutlass. I have the neutral safety and the linkage setup to work as intended when moving the trans range selector by hand without the shifter cable. The problem occurs when the shift cable is attached. I can get the car to start in neutral but if I go back to park it will not start. I have found out if I pull the arm on the column under the hood it will move and then start. I have tried numerous adjustments of the neutral switch and the rod that comes up from the trans to the column and have no luck getting it function as intended .

 

This is where I normally say "read the Chassis Service Manual", but even I have to admit that it's not easy to find the information in it. This is when the GM CSMs started to go right in the toilet (the one for my 1999 Chevy truck is SIX - count 'em - volumes, and it's nearly worthless!). In any case, you need to adjust the backdrive linkage FIRST. Disconnect the floor shift cable and adjust the backdrive linkage per Figure 7-642 in the CSM (pg 7-245). Once that's correct, adjust the floor shift cable per Fig 7-643. Finally, loosen the NSS and adjust it per Fig 9A-135. Hint: there's a hole that you insert an 0.090" drill bit into to lock the NSS in the right position so you can adjust it.

 

Thanks Joe, I had looked on the CSM , and like you say info is real scarce. I will look up the section you noted . I had done the pin thing (after I dissasembled the NSS cleaned and regreased with fresh dielectric and reassembled ) thought maybe some corrsion on the terminals after 40+ years.

 

The internal contacts do wear over the decades, which causes problems.

 

My car was converted from column to floor shift.
Can I disconnect the backdrive linkage and be ok?
Thanks

 

You should make your own thread in the future and not bump old threads of an only somewhat related topic.

That being said, If you disconnect the backdrive linkage on a now-floorshift car, two things will happen:
1. The neutral safety switch will no longer provide protection. If you are ok with this, then leave the collar on the column all the way counter clockwise in park, and the car will start in all gears.
2. You will have no reverse lights under normal operation. To turn reverse lights on, you will have to rotate the collar on the column clockwise to turn them on, and do it by feel. You could put pieces of tape with lines on it to line them up, then turn back CCW when done to turn them off.

Neither of these present a problem, as long as you know what's up.

 

Be aware that factory floor shift cars have the backdrive linkage. There is really no reason to remove it.

 

Oh OK, I didn't know they had both! Thank you
Mine is just really loose so the column doesn't always get into the locked position.

Do you know if there is a bushings kit or something to tighten that linkage up?

 

Sorry, I thought it was a little related but I didn't state why.
My linkage is really loose so I thought I could just disconnect it.
​​​​I appreciate your details on what would happen. I searched alot of threads and could not find that info.

 

As long as you have all the parts and nothing is bent this kit should take care of you.
https://www.ebay.com/itm/19106490479...Bk9SR9zy5dCsYg

 

So back to my post that you quoted above. Read the Chassis Service Manual

Once the feds required the backdrive linkage to lock the shifter, there was no reason to move the NSS to the floor shifter, since the column was still connected. The NSS and backup lights require the backdrive to operate. About once every six months we get a question from someone who removed the backdrive linkage and at some point the collar on the steering column vibrates out of position and they can't remove the key.