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2021 Defender 110 - Transmission Hesitation/Hard Shifts

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Chris P. · rep 0 · May 25, 4:42 AM · 1 replies · solved · Question

Vehicle: 2021 Land Rover Defender 110 P400

Morning everyone,

I'm experiencing some concerning transmission behavior in my 2021 Land Rover Defender 110 (P400 engine). Sometimes, when accelerating from a stop, there's a noticeable hesitation before it engages, almost like a delay. Other times, especially at lower speeds, the shifts feel a bit harsh or clunky, not as smooth as they should be.

It's not constant, which makes it hard to pinpoint, but it's happening more frequently now. I've got about 35,000 miles on it, and I'm still under warranty, but I want to go in armed with some info.

Has anyone else with a newer Defender noticed similar transmission issues? Is this a known characteristic, or should I be worried?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 4:42 AM

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ClearTheCode admin answer:

Transmission hesitation and hard shifts on a 2021 Defender 110 are symptoms that should be investigated, especially with its relatively low mileage. While modern automatic transmissions are complex, these issues can often be resolved.

Common Causes:

  1. Software/Adaptive Learning: Modern transmissions adapt to driving styles. Sometimes, a software update or a transmission adaptive reset (re-learning) can resolve erratic shifting patterns.
  2. Low or Contaminated Transmission Fluid: Although less common on newer sealed units, incorrect fluid levels or contaminated fluid can impact shift quality. The ZF 8-speed transmission in your Defender is a sophisticated unit that requires specific fluid.
  3. Valve Body Issues: The valve body controls the hydraulic pressure that engages the clutches. Malfunctions here can lead to delayed engagement or harsh shifts.
  4. Solenoid Malfunctions: Solenoids within the valve body direct fluid flow. A faulty solenoid can cause incorrect or delayed gear engagement.
  5. Mechatronic Unit Problems: This integrated unit combines the valve body and transmission control unit (TCU). Issues here can manifest as various shifting problems.

When to See a Shop:

Since your vehicle is still under warranty, it's imperative to take it to a Land Rover dealership for diagnosis. They will:

  • Scan for Codes: Check for any stored transmission control module (TCM) fault codes (e.g., P07xx series).
  • Check Software Versions: Verify if there are any outstanding software updates for the transmission.
  • Perform Adaptive Reset: If no hardware fault is found, they may perform a transmission adaptive reset.
  • Inspect Fluid Level/Condition: Although a sealed unit, a dealership has the proper tools and procedures to check the fluid.
  • Test Drive and Replicate: A technician will likely test drive the vehicle to experience the symptoms firsthand.

Do not delay, as transmission issues can worsen over time. Document the occurrences (when, what speed, what gear) to help the technician diagnose the problem.

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