So the fault code says either your A-clutch or D-brake is slipping in 1st gear, yet the other gears which use the same clutch & brake are working fine. Certainly a tricky one to diagnose. The 6HP26 has around half-a-dozen common faults, but this isn’t one of them. I think I’d probably remove the...

The code is telling us that a clutch is slipping in 1st gear. The A-clutch and the D-brake are the friction elements used for 1st gear. The A-clutch is also used in 2nd, 3rd & 4th gears. The D-brake is also used in Reverse. Do you have an issue with Reverse, at all? So, unless you actually come...

If your front propshaft rotates in Drive and Reverse with the vehicle stationary (wheels not rotating) then your issue has nothing to do with your transfer box. As I said before, it’s either your front propshaft spline (which now seems unlikely, as you have the latest design) or one of your...

This is the visible difference between a vehicle that’s had the Q041 Service Action (which added a flexible joint at the final drive end to prevent spline misalignment) and the original design without the flexible joint Phil

If the front propshaft is rotating with the vehicle stationary then either the final drive/propshaft spline has failed (although the vehicle should have had the Q041 Service Action to prevent this) or one of the driveshafts has popped out Phil

Arto has a 2008 model, so he’s lucky enough to have the ZF 6HP26X transmission :) Phil

ZF Lifeguard Fluid 6 isn’t cheap stuff, but using it is the only way to guarantee you have the correct friction modifier pack for the optimum control of the clutches. On eBay you can buy it for around £15/litre. There are a lot of cheap(er) pattern sump pans/filters about, but the genuine OEM...

Have they sold you a drain plug rather than a filler plug? Do you mean the steel pan conversion? This is really for RRS/LR3/LR4 owners whose vehicles have a cross-member passing under the transmission sump which prevents it being removed without having to unbolt an engine mount and jacking up...

Some of your symptoms align with a worn rear stator bush e.g. only gears 1-3 available, worse when hot: https://www.landyzone.co.uk/land-rover/help-please-gearbox-issue.330768/#post-4269229 However, this issue usually manifests itself during acceleration, where the transmission refuses to...

I agree with Datatek’s suggestion. How confident are you, when you installed the torque converter, that you correctly engaged the impeller hub onto the drive tangs on the oil pump? If the slots aren’t aligned with the tangs correctly, the drive tangs will shear off when you tighten the...

I would remove the Mechatronic unit and check the E-clutch feed port with air pressure to determine if the rear stator bush is worn & leaking. It’s also an opportunity to check the bridge seal & the 4 rubber jump tubes...

I’d be surprised if you could find a new one for sale, and if you did it would be phenomenally expensive. Ideally you would have to replace the two annulus gears as well, because they bed-in to the micro-geometry of the meshing gears over tens of thousands of miles (noise issue). Epicyclic...

Presumably they’re referring to the planetary assembly, which is a ‘sealed unit’ in as much as the planet pins are pressed into the carrier and it therefore can’t be disassembled. Phil

If you stare hard at the rev counter needle while the rumble/vibration is happening, do the engine revs fluctuate slightly (i.e. only by a couple of hundred rpm) in sync with the noise? Does the noise disappear if you select Manual mode? Phil

I’m guessing you have a 3.0 TD6 and not a 4.4 V8? If so, it could be the direct clutch hub that has sheared its drive shaft. Direct clutch is applied in 4th & 5th gears on the 5L40-E. Phil

When Land Rover went to the expense of carrying out the Q041 Service Action on all the 2002-2005 L322s (2002-2006 for the diesels) they chose not to risk upsetting the pinion bearing preload and consequently each final drive was rebuilt with a new collapsible spacer and tail bearing (process...

It's usually the internal spline in the drive tube which wears, together with the corresponding external spline on the end of the propshaft Phil

The 3.0 litre diesels were fitted with the infamous GM transmission. This changed to the ZF 6HP26X unit when the engine was replaced with the 3.6 TDV8 for 2007MY. All 5-speed transmission cars had the NV225 transfer box. This was replaced with the Magna Steyr DD295 unit when the 6-speed...

I don't know if there's anything in this video that might help : By the way, you have a GM 5L40-E transmission and a New Venture Gear NV225 transfer case. Phil

Totally agree. If it turned out to be an issue with, say, your inhibitor switch (= fault code P0705) the replacement transmission probably wouldn’t have a switch on it anyway and you’d be expected to use your old one. If you’re thinking you’ll be keeping the vehicle for a while it might be...