Hi everyone,

I have a 2013 Land Rover LR4 5.0 V8 with ZF 6HP26X at 195,000 km.

Background:

• For over a year I had occasional very soft 3-4 slip.
  
• Recently the shop did a pan + filter service using OEM Carter LR007474 + ZF Lifeguard 6 and added 7 quarts
  
• After pickup the 3-4 flare/slip became more noticeable and I started getting P0783 code + intermittent limp mode every time slips occurs. Feel like a kick similar to when you are learning to driving manual and do it wrong
  
• I performed one adaptation reset with my scanner; the mechanic already did one while service the trans. Big mistake , symptoms worsened after the resets.
  
• I took my LR4 to show and we later corrected the fluid level properly (it was overfilled) using the official ZF procedure at exactly 40 °C (only small drops from the fill plug).
• Oil doesnt looks or smells burnt, just normal powder on magnets. Have to cut filter inlet pipe to remove. Have not records from previous services , im second owner
  

Current situation (after ~200 km total of gentle driving since level correction mostly on M mode 120 / 200 km of gentle highway):

• soft flare/slip specifically on the 3→4 shift, especially when I apply throttle immediately after the shift. Most noticeable on auto mode on D
  
• P0783 code appears intermittently and triggers limp mode/transmission fault warning every time error occurs (clears on ignition cycle or with scanner).
• Some times it triggers even without a noticeable slip
• 4-5-6 shifts are very smooth.
  
• Clear pattern noticed: If I wait 1-2 seconds after selecting 4th (until tachometer stabilizes), the shift is clean. If I accelerate right away, it flares softly and may set the code.
  
• ATF temperature stable around 80-85 °C when hot.
  

Has anyone experienced this exact same scenario after correcting an overfill + performing two adaptation resets on the 6HP26X?

Did it fully resolve with more gentle miles (and how many more), by doing the official ZF drive cycle, or did you eventually need solenoids/mechatronic work?

Any experiences or advice would be greatly appreciated.

Thanks in advance!

 

It sounds like a mechanical issue. Overfill is suspect as the culprit, these trans are more sensitive to underfill.

At a minimum you will need to rebuild the valve body with a zip kit and a set of solenoids.

it might only be a temporary fix though. There are brass bushings in between gear packs that wear out and cause those shifts in most cases.