* Shift Linkage: This is the most common cause. Over time, the linkage components (cables, rods, bushings) can wear out, become bent, or accumulate debris, causing binding and sticking. This is particularly likely given the age of the vehicle.
* Shift Cable Adjustment: The shift cables might be out of adjustment, causing them to be too tight or too loose. Incorrect adjustment can lead to binding and difficulty shifting.
* Transmission Problems: Issues within the transmission itself, such as low transmission fluid, worn internal components, or a failing shift solenoid (if electronically controlled), can make shifting difficult. A problem here might manifest as resistance *during* the shift, not necessarily sticking in Park.
* Park Pawl: The park pawl is a mechanical device that locks the transmission in the Park position. If it's worn, damaged, or improperly engaged, it can cause resistance when trying to shift out of Park. This is a more serious potential problem.
* Steering Column: Sometimes, issues within the steering column, specifically the shift linkage connection point, can interfere with smooth shifting.
* Shift Interlock Mechanism: The interlock prevents shifting out of Park unless the brake pedal is depressed. A problem with this mechanism could prevent the shift or cause sticking. This usually results in complete inability to shift, rather than occasional sticking.
* Fluid Leaks: Low transmission fluid levels can cause various shifting problems, including sticking. Check the fluid level and condition. Dirty fluid is also a red flag.
Troubleshooting Steps:
1. Check Transmission Fluid: Ensure the transmission fluid level is correct and the fluid is clean and not burnt. Low or dirty fluid is a common cause of shifting issues.
2. Inspect Shift Linkage: Visually inspect the shift linkage for any signs of damage, bending, or excessive wear. Look for any binding or stiffness in the cables or rods.
3. Try Lubrication: Apply a small amount of lubricant to the linkage points (if you're comfortable doing so). This might temporarily improve the situation if it's due to friction.
4. Check Brake Pedal: Make sure the brake pedal is fully depressed when attempting to shift.
5. Check for Obstructions: Is anything interfering physically with the shifter movement?
If you're not comfortable performing these checks yourself, take your Suburban to a qualified mechanic. Improper diagnosis and repair could worsen the problem or lead to more costly repairs later. The problem could be minor (adjustment) or major (internal transmission damage), so professional help is crucial for determining the correct course of action.
