Hey folks, I've noticed my 2001 disc 2 won't start unless the vehicle is firmly in the park position. Sometimes just giving the shifter a firm push forward in the park position is enough for the truck to then start. I've noticed a little leak underneath so perhaps a seal is failing. Any thoughts?

 

It may be a failing or misadjusted XYZ switch (aka the starter inhibitor switch).

When the shift lever is moved it not only physically shifts the transmission but it also rotates a switch mounted on the side of the transmission (the XYZ switch). The XYZ tells the computer what gear has been selected and if the computer isn't told the truck is in Park or Neutral it won't allow the starter to be engaged.

The computer also sends the signals to display PRND321 in the instrument panel and to display the red LEDs on the shifter surround that also indicate PRND321. Try moving the shifter through the PRND321 range to confirm whether or not the instrument panel indicators and red LEDs illuminate as they should. If they do not do so consistently you can first try adjusting the XYZ switch as shown in the RAVE. The RAVE shows that a special tool is needed for the adjustment but it can also be done without the tool.

A 1/4" ratchet with a 10mm socket works best to make the adjustment. Use the 10mm socket to loosen the two bolts that secure the switch to the transmission. Loosen them but do not remove them. Make sure the truck is parked on a level surface with the parking brake engaged and the wheels chocked. With the bolts loosened the switch can be rotated a few degrees left and right on the shaft on which it is mounted. Have someone else sit in the truck and observe the instrument panel gear indicator. With the shifter in Park rotate the switch until the P is displayed, then tighten the mounting bolts. Once the bolts are tightened have your helper move the shifter through its PRND321 range to confirm that the instrument display and the red LEDs illuminate as they should. Repeat as necessary.

If this adjustment does not solve your problem you may need to replace the XYZ. New XYZs are crazy expensive. You can remove yours and rebuild it, or you can buy a used one from Paul Grant that he has tested and confirmed good. Then rebuild your old one and keep it as a spare.

 

Following up. I've yet to follow through on your suggestion. Now the vehicle won't start unless ignition key is on, gear in neutral, foot on brake and then she starts. Still the same prognosis? Thanks

 

When I did my 04 CDL Linkage install into my 02 Kalahari I had to remove the PRND321 assembly as it was in the way. I disconnected the 13mm connection at the shifter cable itself down at the XYZ switch.

When I put it all back together I guessed where it went and for about 2 days I was fine. Then at a gas station of coarse it wouldn't start. Since I had noticed the PRND321 was stiffer I figured it was slightly out of adjustment so I just applied some pressure to the shifter **** and it started right up. I got home, crawled under my D2, loosened the 13mm and gave it just a little maybe 1-2mm more play and bingo no problems since.

I'd give that a shot before messing with the actual XYZ switch on the transmission.

 

Somebody is going to have to go underneath your D2 with some wrenches and probably get dirty.

Loosen bolts #4 1st page for switch adj. Nut #3 2nd page for cable.

Take tools for both scenarios and have a body inside unless you want to have check your own adjustment results.

Should be less than a 30 minute job once you have tools together.
......

 

Yeah it took me maybe 2min, loosen nut, gave it 1-2mm of slack, tightened nut, tested it.