My 2003 Express 3500 with 160,000 miles just stopped engaging Park but goes into all of the other gears. The indicator shows its in Reverse, and the van goes backwards in reverse AND when the shifter is in the Park position, even though the shifter feels like it clicks into Park. I do need to shift into N to start the ignition.
Where should I start in diagnosing this?

 

Today, I started at the shift lever and tracked the cable until I found a broken section of cable cover under the van. I replaced the lower cable and after making necessary adjustments, I have full range of motion at the gear shift lever BUT the new cable isn't locking onto the the gear shift lever... I'll buy a new one and hopefully that fixes it but until now, the cable is zip tied in place onto the arm.