The APDTY 163933 tailgate lift assist dampening shock is a direct-replacement rear right shock assembly designed for 2015-2020 Ford F-150 pickup trucks. Mounted behind the passenger-side tail light, this viscous dampening shock controls tailgate descent and prevents slamming when opening, replacing Ford OE part number FL3Z-99406A10-A. When this shock fails, your tailgate drops too quickly or won't stay up, creating safety hazards and potential damage to the truck bed and tailgate itself.
Key Takeaways
- Factory position rear right shock (behind tail light) for 2015-2020 Ford F-150
- Controls tailgate descent speed and prevents slamming during opening
- Replaces Ford OE part number FL3Z-99406A10-A
- Viscous dampening technology provides smooth, controlled motion
- Check APDTY compatibility chart to verify your specific vehicle before ordering
Buy APDTY 163933 directly from APDTY
What Does the Tailgate Lift Assist Shock Do?
The tailgate lift assist shock is a hydraulic dampener that controls the speed at which your tailgate opens. When you release the tailgate latch, the shock's internal viscous fluid creates resistance that slows the tailgate's descent, preventing it from dropping rapidly under its own weight. This controlled motion protects both the tailgate hinges and the truck bed from impact damage while reducing injury risk to anyone standing behind the vehicle.
On the Ford F-150, two shocks work together—one on each side of the tailgate. The APDTY 163933 replaces the rear right shock positioned behind the passenger-side tail light. Both shocks must function properly to provide balanced, smooth tailgate operation.
What Are the Symptoms of a Failed Tailgate Shock?
Tailgate lift assist shocks fail gradually as internal seals wear and hydraulic fluid leaks out. You'll notice these warning signs:
- Tailgate drops too quickly: The gate falls rapidly when opened, potentially striking your legs or the bumper
- Uneven descent: One side drops faster than the other, causing the tailgate to twist or bind
- Tailgate won't stay open: The gate drifts closed on inclines or falls immediately after opening
- Visible fluid leakage: Oil residue on the shock body or mounting points
- Noise when opening: Creaking, popping, or metal-on-metal sounds as the tailgate opens
- Difficulty closing: Extra force required to latch the tailgate due to misalignment from uncontrolled descent
Failed shocks also accelerate wear on tailgate hinges, cables, and latch mechanisms. Replacing worn shocks prevents expensive secondary damage and maintains safe tailgate operation.
Which Ford F-150 Models Does APDTY 163933 Fit?
According to APDTY's verified fitment data, the 163933 tailgate shock is compatible with 2015-2020 Ford F-150 pickup trucks. This shock is designed for the rear right (passenger side) position behind the tail light.
Important: Always verify your specific vehicle year, make, and model using the live compatibility chart on APDTY's product page before ordering. Vehicle-specific variations in cab configuration, bed length, or equipment packages may affect fitment. The compatibility chart accounts for these factory differences and ensures the correct match for your truck.
If you're unsure about your vehicle's compatibility, check the compatibility chart or compare your existing shock's mounting configuration with the product images.
APDTY 163933 Specifications and Part Number Cross-Reference
| Specification | Details |
|---|---|
| APDTY Part Number | 163933 |
| Position | Rear Right (Behind Tail Light) |
| OE Part Number Replaced | FL3Z-99406A10-A |
| Shock Type | Viscous Dampening (Hydraulic) |
| Fitment | 2015-2020 Ford F-150 |
| Condition | Brand New |
| Assembly Type | Complete Bed Tailgate Shock Assembly |
This is a complete shock assembly ready for direct installation. No additional components are required, though many technicians recommend replacing both left and right shocks simultaneously to maintain balanced tailgate operation and prevent uneven wear on the replacement shock.
How to Replace a Ford F-150 Tailgate Shock
Tailgate shock replacement on 2015-2020 F-150 trucks is a straightforward job requiring basic hand tools. The rear right shock is accessed from behind the tail light assembly on the passenger side of the truck bed.
General replacement process:
- Support the tailgate: Have an assistant hold the tailgate or use a support prop to prevent it from falling when the shock is removed
- Access the shock: The rear right shock is located behind the passenger-side tail light area; you may need to remove trim panels or the tail light assembly for access depending on your specific F-150 model
- Remove the upper mounting bolt: Use the appropriate socket to remove the bolt securing the shock to the truck bed frame
- Remove the lower mounting bolt: Detach the shock from the tailgate mounting bracket
- Install the new shock: Position the APDTY 163933 shock with mounting points aligned, install lower bolt first, then upper bolt
- Torque to specification: Tighten mounting bolts to Ford's specified torque values (consult your service manual)
- Test operation: Slowly open and close the tailgate several times to verify smooth, controlled motion
Safety considerations: Never work under an unsupported tailgate. The tailgate weighs 50-70 pounds depending on model and will fall rapidly if the remaining shock fails or releases during service. Always wear safety glasses when working under the vehicle, and inspect the opposite shock while you have access—if one has failed, the other is likely near the end of its service life.
If you're replacing only the right shock and notice uneven tailgate operation afterward, the left shock has also deteriorated and should be replaced to restore balanced function.
Frequently asked questions
Do I need to replace both tailgate shocks at the same time?
While you can replace just one shock, Ford technicians recommend replacing both left and right shocks together. Shocks age at similar rates, so if one has failed, the other is likely weakened. Replacing both ensures balanced tailgate operation and prevents the new shock from wearing prematurely due to compensating for a weak opposite shock.
Will this shock work on earlier or later Ford F-150 models?
The APDTY 163933 is verified for 2015-2020 Ford F-150 trucks only. Do not assume compatibility with other model years without checking the compatibility chart on APDTY's product page, as Ford changed tailgate shock designs, mounting points, and hardware across different generation F-150 trucks.
How long do tailgate lift assist shocks typically last?
Tailgate shocks generally last 5-8 years or 60,000-100,000 miles depending on usage frequency, climate, and load conditions. Trucks in commercial use or harsh environments (extreme heat, cold, salt exposure) experience shorter shock life due to accelerated seal wear and fluid breakdown.
Can I drive with a failed tailgate shock?
Yes, but it's unsafe and risks damage. A failed shock allows the tailgate to drop uncontrolled, creating injury risk and potentially damaging hinges, cables, the bed, and the tailgate itself. Replace failed shocks promptly to restore safe operation and prevent secondary damage to more expensive tailgate components.
The APDTY 163933 tailgate lift assist shock restores controlled, safe tailgate operation to your 2015-2020 Ford F-150. This direct-replacement rear right shock (OE part FL3Z-99406A10-A) installs behind the tail light and eliminates dangerous tailgate drop, protecting your truck and preventing injury. With 47 units in stock and availability across APDTY.com, eBay, and Amazon, you can quickly source this critical safety component. Verify your vehicle's compatibility using the live chart on the product page, and consider replacing both left and right shocks together for balanced performance and maximum service life.