Does the transmission perform okay when it’s cold and then failsafe appears only once it has warmed up and then it reverts to working okay again once it has cooled down i.e. failsafe disappears? Or is the failsafe message there all the time? Is it definitely failing safe into 5th gear rather...

Early L322s used the New Venture Gear NV225 transfer box (i.e. petrol models to 2006MY and diesel models to 2007MY, both with 5-speed transmissions). This transfer box was unique to the Range Rover and wasn’t used in any other vehicle. Once the 6-speed transmission was introduced, all...

So this is a very early 6-speed model? I wonder if the output shaft spline has failed through fretting corrosion (they neglected to lubricate them at the factory). Does the park lock hold the vehicle with the handbrake off? Phil

This part of the connector stays attached to the metal bracket bolted to the top of the bellhousing so you will need to unbolt the bracket to access the pins for continuity testing. The half of the connector that is part of the vehicle wiring loom (shown in grey in the diagram below) twists...

Depends. Is it a 3.6 litre TDV8 (= ZF 6HP26/ZF Lifeguard Fluid 6) or a 4.4 litre TDV8 (= ZF 8HP70/ZF Lifeguard Fluid 8)? Phil

Or the output shaft spline has failed through fretting corrosion. Hopefully just your transfer box, though…

That diagram shows the straight-forward 5HP24 system from BMW. The circuit for the 6HP26 in the Disco 3 is a good deal more complicated :) Phil

I’m sure that you are already aware but, just in case, it might be worth highlighting that the BMW-engined petrol and diesel L322 final drives have a different ratio. M62 4.4 V8 = 3.727 (41T/11T) M57 3.0 TD6 = 4.100 (41T/10T) Phil

From JPAT: Shaft, Direct clutch hub and shaft 191mm long, JPAT p/n N224 29 04 = £93.75 +VAT Phil P.S. We should just keep in mind that we don't know for certain that this component has failed and caused the issue with 4th & 5th gears so I certainly wouldn't recommend shelling out for one...

I have an account with JPAT and I’m ordering some (ZF) parts from them tomorrow so I’ll ask them to quote for a 5L40-E direct clutch hub/shaft at the same time. Phil

Well that didn’t take a lot of persuading! Hopefully you will have received the repair manual(s) by now. 100% agree regarding the feeling you’ll have after fixing your own transmission – you’ll never worry about it again. Sonnax produce a large selection of replacement valves for the 5L40-E...

If you message me with your email address I can send you the official repair manual. The cheapest method of dealing with the piston seals is probably to use the Seal-e-Zee cones and freezing spray. https://www.hydratest.co.uk/transmission-tools Phil

If you’re capable of undertaking a manual gearbox conversion then you’re more than capable of re-manufacturing a 5L40-E transmission. Why don’t you rebuild your transmission yourself to ensure that, this time, it’s done properly? If you get the valve body assembly fitted with Sonnax valves this...

The bolt pattern for the E53’s NV125 transfer box is not the same as the NV225 (which was unique to the L322). I think, along with the electrical/electronic/control issues mentioned by holidaychicken, such a conversion would be extremely challenging. Phil

https://www.landyzone.co.uk/land-rover/is-it-the-dreaded-box.222192/page-2#post-2525905 Phil

Have you lost 4th AND 5th gears? It's highly significant if your transmission can't select 5th either (using manual mode). The torque converter lock-up clutch is automatically disengaged if failsafe mode is flagged. Phil

For the ZF 5HP24 transmission, the relevant dimension from the bellhousing face to the four mounting pads is 25mm, when the torque converter is installed correctly. To prevent damage to the input seal, caused by converter movement during shipping, my transmissions are all supplied with the...

Does this happen in Sport mode as well as ‘normal’ mode? Are all the brake lights working? Phil

Not sure if this is of any use : Phil

Possibly a problem with the Manual/Sport switch on the gear selector lever? Phil