Removing the (Automatic) shift knob

fiat-124-spider-28

at-shift-knob

an MX-5 knob is illustrated here, whereas the 124 Spider knob is squarish


✅ linefeed reported on 2/14/2019, that the linkage within the 124 Spider’s automatic shift knob appears to be much simpler than the Miata’s, so the (rod) concern that I was relaying based on Mark Booth’s experience may not be applicable.  However, DennyA reported on 4/21/2019, that his rod had popped out, and that linefeed was just lucky, so review the [UPDATE 11/12/2018] section below.


For those that need to remove the shift knob in order to replace the leather boots (shifter and ebrake boots) with alcantara versions, or simply don’t like the feel of Fiat’s square knob and perhaps wish to substitute it with the round MX-5 version (Mazda # N247-46-030A), here is the removal procedure:

AUTOMATIC TRANSMISSION SHIFT KNOB REMOVAL

  1. Engage parking brake.
  2. Shift the selector lever to the N range.
  3. Insert the tool (width: 2 mm {0.08 in} or less, thickness: 1 mm {0.04 in} or less) on the rear side, as shown in the figure.
  4. Lift the tool horizontally in the direction of arrow (1) shown in the figure and detach the tab, and then remove the lock release button cover in the direction of arrow (2).
  5. Remove the spring.
  6. Remove the selector lever knob.

[UPDATED 11/12/2018]

For MX-5 and 124 Spider owners with automatic transmissions, that are removing trim to install the retrofit kit, it is advised that you try to work around removing the shift knob, as the linkage for the shift knob button, is VERY difficult to reassemble.  Better to shift into neutral to give you clearance to pry the shift boot surround, and then raising it enough to avoid scratching the console while rotating it 90 degrees to the counter-clockwise.

Mark Booth shared this story that resulted from following the instructions (removing the shift knob)…

I’ve helped install CarPlay/AA in two NDs with automatic transmissions. With the first one we ran into the following problem:

Before the interior was fully reassembled we tested CarPlay. Everything was fine. But after we reassembled the interior we tested again. It worked fine UNTIL we pressed the start/stop button to turn off the car. To our surprise, the infotainment display remained ON and an “Ignition is on” warning was displayed in the leftmost gauge display. The light on the start/stop button was a solid amber color. Even after 4-5 minutes the infotainment display remained on. We started the car (it started fine) and then stopped it. Again, tine infotainment display remained on. It wouldn’t shut off and the ignition is on warning persisted.

We disassembled the interior again, reseated all of the wiring connectors, and tested the car with the interior only partially reassembled. It worked fine. Thinking it must have been a loose connection, we reassembled the interior. Oops, with the car fully assembled the problem returned. What the hell???

It took awhile to figure it out but we finally did….

Under the automatic transmission’s shift knob there is about a 4-5 inch long white plastic rod (part of which is black) that sits vertically inside the metal shift shaft. This plastic rod is only about 3/8-inch in diameter and its bottom is forked. The upper end of the plastic rod isn’t flat, it has a raised ridge that is oriented in the same direction as the forked bottom.

The plastic rod sits between the underside of the button that is on top of the shift knob and a release mechanism down below metal shift shaft. This allows the shift lockout mechanism to be disengaged when you press the button on top of the shift knob.

Turns out that forked end of this plastic rod MUST be positioned exactly at 6 o’clock/12 o’clock down inside the shift shaft. It is possible to position the plastic rod at another position (3 o’clock/9 o’clock, for instance) and you can still reinstall the shift knob. However, when that little plastic rod is in an incorrect orientation, the release mechanism down below the shift shaft is being depressed and has the same effect as manually pressing down on the button on the shift knob.

Automatic transmission owners, try this for yourself… Go out to your car, start it, hold down the shift knob button (while car is still in park) and then press the ignition button to turn off the car. The car’s motor will stop but the infotainment display won’t shut off. “Ignition is on” will be displayed in the left gauge. (You fix it by starting the car again and then turning it off without pressing the button on the shift knob).

When the little forked end of the plastic rod is in its correct position the little rod can’t be turned very far. The fork sits over a tab down inside there. But here’s the rub….

It’s possible to put that little plastic rod down into the shift shaft so it’s oriented a few millimeters outside of 6 o’clock/12 o’clock. In that slightly-off position, the little fork is engaged over the little tab BUT it is also not fully seated. It is probably only about 1-2 mm too high in that position and, amazingly, that is all it takes for the above symptom to happen when you try to turn off the car.

We never intended to mess with the white plastic rod. We accidentally dislodged it (pulled it up) while removing the shift boot. We thought we reseated it properly (it wouldn’t turn) but it was oriented slightly outside the 6 o’clock/12 o’clock position. Oops.

It was a real brain teaser. We spend more than an hour trying to figure out what was causing the problem. We kept thinking it was electrical (for obvious reasons) until we got everything reassembled EXCEPT the shift knob and the car worked fine. Put the shift knob back and the infotainment display wouldn’t shut off. That’s when we finally realized it had something to do with the shift knob.

I hope this saves some other automatic owner the aggravation we experienced!

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s