I agree with the others - the symptoms you've described do sound a lot like those you'd expect from a worn torque converter lock-up clutch friction plate. Worth staring closely at the rev counter needle during the vibration to see if the engine speed is wavering a couple of hundred rpm in...

I think it’s worth bearing in mind that solenoid failures are few and far between with the 5HP24. Your issue is much more likely to be the ‘normal’ B-clutch hub/C-clutch drum axial bearing wear, and subsequent failure of the A-clutch O-ring. How sure are you that your transmission is failing...

My advice would be to forget it. If you really want a diesel L322 with a 6-speed transmission then sell your TD6 and replace it with a 3.6 TDV8 (2007MY onwards). There are insurmountable mechanical issues with the conversion (different engine RFOB interface, torque converter not matched...

Err, no you haven’t. If you temporarily disconnect the 20-pin connector at the back of the transmission this will force the transmission into mechanical/hydraulic failsafe which is totally independent of the electronics & ECU. You should be able to select reverse and move backwards as usual...

Could be that the 'toilet roll' (direct clutch) shaft has sheared : is it the dreaded box Phil

Could be that the lock-up clutch is malfunctioning. You can replace the complete torque converter without having to open up the transmission, but the transmission has to come out unfortunately. A re-manufactured torque converter costs around £250 (exchange). A less likely cause is a faulty...

You should be very wary of resetting the adaptions when you change the fluid. If you have solenoid issues (unfortunately very common on the 6HP26) this could result in you trashing the transmission. Land Rover specifically instruct their workshops not to do this. The adaptions should only be...

The 4.4 TDV8 was the only L322 model which didn't feature a cable operated park lock actuated by the gear lever. I believe they call it progress. Phil

Does it definitely failsafe into 4th gear or could it be 5th? : Autobox L322 Phil

Yes, petrols got the 6-speed transmission and the Magna transfer box for 2006MY but the diesels had to wait another year longer. Phil

Depends which year your L322 is. The earlier New Venture Gear NV225 transfer box (used with the ZF 5HP24 and GM 5L40-E transmissions) uses Castrol BOT 26 FMB1 fluid (1.0 litre capacity). The later Magna Steyr DD295 transfer box (used with the 6-speed transmissions onwards) uses Shell TF 0753...

I'm not sure how easy the bushes are to source individually, but you can certainly get hold of a full transmission kit of OEM bushes for around £65 (for example : https://www.onestopgearboxshop.com/bmw-zf-oe-6hp26-automatic-transmission-gearbox-bush-kit-14-pieces) Phil

Does sound like a worn rear stator bush. You could remove the mechatronic unit and apply air pressure to the E clutch and see if it leaks badly. Phil

The Park/Neutral switch in the 6HP26 is part of the Mechatronic unit, not the gear lever assembly Might be worth checking the Mechatronic connector? Phil

L322 Towing Electric's Relay I.D. Phil

Is your L322 a 4.4 V8 or a 3.0 TD6 (they have different transmissions)? There are many faults which can cause the transmission to go into failsafe mode, including reasons that have nothing to do with the transmission e.g. low battery voltage, or a faulty transfer box shift motor potentiometer...

Yet another possibility – the inhibitor switch on the transmission prevents the starter motor cranking the engine unless it detects that the transmission shift lever is in Park or Neutral. These switches are frequently problematic because they’re exposed to the elements, underneath the vehicle...

Transmission fluid overheating (and the resulting selection of cooling strategy mode by the transmission ECU to inhibit upshifts) is generally caused by restricted flow in the radiator (which you have replaced) or the oil cooler. A faulty fluid temperature sensor is another possibility. You...

Is the message centre displaying ‘Trans Failsafe Prog’? This locks the transmission in 4th gear, which may be what you’re describing when you say “The vehicle will drive on a flat surface. The engine just revs and the transmission will not provide enough power.” The fact that it won’t engage...

Phil