Thread: 2011 D4 'Gearbox Fault' warning

Very interesting read. I have been experiencing similar transmission issues for some time though not as frequently.
If I give it too much throttle it will slip out of the gear, not sure of which and going into F limp mode with what I suspect is 3rd selected and high RPM. Lock / unlock 3 times clears it and off I go again.
Similarly if I give it too much going up a hill or use cruise control it will try to down shift, doesn't like something and jump back to the high gear then go into limp mode with again 3rd selected.

If I use light throttle around 2k it will behave. I have had TC shudder about 5 years ago and did a tripple flush, new valve body seals, filter and some Dr tran and it settle it down for a long time though it would still present slipping.

I do not get the HPFP codes the OP was getting.
I did a trip Hervey Bay to Gold coast and back with only one fail event and that was me getting cocky going up a hill with too much throttle applied.

I am starting to feel slight what I expect are TC shudders and small deviations in RPM in alignment with said shudders, not major though.
I do get slippage in middle gears, think 3rd is worst but also 4th.

Most of the U codes are cascading CANBUS faults. Below is the fault from recent trip to Gold Coast and back ~ 9 hour round trip.

L319 - Discovery 3 2008
Vehicle scanned on 20-05-2024 15:10
Using IIDTool BT V3.0 B2742
Engine TDV6

• U0416-00 (28) Invalid data received from vehicle dynamics control module

Instrument Pack

• U0132-87 (28) Lost communication with ride level control module - Bus signal/message failure - missing a message

Terrain Response

• U0402-94 (20) Invalid data received from transmission control module - Component failure - unexpected operation
  ( on 11-05-2024 15:08:22 at 355152 km )

Transmission

• P0730-00 (60) Incorrect gear ratio
  ( on 11-05-2024 15:04:04 at 355146 km )
• P0735-00 (60) Gear 5 incorrect ratio
  ( on 11-05-2024 15:08:21 at 355152 km )

The vehicle was a bit sluggish and at last service before doing the GC trip I cleaned both MAF & MAP sensors which seemed to improve things.
I also tightened the top and bottom clamps on the top intercooler hose as I had a bit of an oil film over the blue silicon intercooler hose though could not find any splits, no hissing and no black smoke under load.

I am thinking the ZF will need a full rebuild inc TC & valve body. It has about 355k on it. My LR indie is making some enquiries on getting it done, send to Sunny coast auto trans rebuilder or down to ZF in Sydney.
Neither is a cheap option.

Hopefully I do not get the dreaded HPFP issue others have had.

cheers
Peter

I had planned to do the solenoids, seals and zip kit this long weekend but I didn't get around to ordering parts on time. Instead I figured a 3.5 hour trip south as the first proper test of the new HPFP and a weekend of only minor Land Rover tasks. (My usual commuter run is 17 mins of less than 50 with one 3 min stretch at about 70kph. Poor car.)

But the Discovery appears to have other plans for me this weekend. About 1.5 h into the trip last night I get Restricted Performance and P023D-22 (2F). Bugger.

Stop, clear code, restart, power - another code. And so on till I reached my destination. Even with the Restricted Performance error in the dash, the car doesn't actually go into limp mode and will sit on 100 easily enough.

Google suggests this vid: https://www.youtube.com/watch?v=jcKpRylro50

So I check the actuator in the morning to find the same as in the video (actuator moves when cycling the ignition), but same as in the video there's oily gunk on the hose from the turbo to the engine intake. So I clean it off and find that the hose clamp is about 3 full turns of the worm loose. So after tightening it reassembling things and taking a drive I put my foot down. I get a puff of black smoke (nothing too crazy but blacker than I have ever noticed before) and I get the same code. Double Bugger.

So I keep driving for about 5 mins without planting it but letting it creep up to 100. No codes. So I stop, plant it and the car leaps into life like I have not know it to do on my regular commutes to work. No smoke at all. Stop, fang it again and again. Same. No codes, no smoke, great acceleration.

So I count it as a lucky win until I decide to do a victory lap this afternoon and the bad behavior is back. Restricted Performance, P023D-22 (2F). Stop, clear, restart, repeat: I get the code 4 times in the first 5 mins or so of the drive. So I drive on with a light touch for another 15 mins till I get to somewhere I can floor it again. This time no codes, no smoke, great acceleration. I did a ton of acceleration tests all the way back with no codes and great acceleration. (Fully aware of double demerits today). What the heck? Car is going like a champion.

I had the GAP IID logging the trip not really knowing what to read but the 'Boost pressure actuator - Bank 1' value never went above 0.870% even at full acceleration when I am sure the turbo must have been turbo-ing it's little heart out. It would drop as low as 0.522% when coasting. Do these values read 2 decimals out and are trying to say 52 to 87% boost? Is this even a valid live value to help diagnose this issue?

Anyway, a head scratcher for now. I'll try again tomorrow.

Any ideas? Thanks!