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...

A common problem with the 5HP24 transmission, particularly in the L322, results in an issue with the A clutch. As the A clutch is used in gears 1, 2, 3 & 4 the transmission consequently fails safe into 5th. However, as your transmission fails safe into 4th (A & B clutches applied) – which is the...

How certain are you that your transmission is failing safe to 4th gear rather than to 5th? This is very significant. Phil

Yes, the majority of the flow from the pump goes through the torque converter, which flushes the debris out into the fluid. Once the friction material has completely worn off the LUC friction plate, the steel backing plate then begins to wear, depositing metallic debris into the fluid...

Typical conditions for shuddering (due to wear of the torque converter lock-up clutch friction plate) are at light throttle openings on a slight incline. This is because the LUC is operating in its ‘continuous slip’ mode, to minimise the transmission of torsional vibration through the driveline...

As Saint.V8 has already stated, the ZF transmissions are very straightforward to strip & rebuild. The hard bit is getting the damn thing out of the vehicle & back in again afterwards. Worth having a glance through the Repair Manual to see what you think ...

From '07-'12MY the front driveshafts are the same i.e. RH = IED500110, LH = IED500120. Similarly, the rear driveshafts are the same i.e. RH = TOB500310, LH = TOB500320. Phil

Just to highlight the OP has a 2006 model with the ZF 6HP26X transmission. The design of the front propshaft had been changed by that stage to include the front joint, so the Q041 Service Action isn’t applicable to this vehicle. If you hear the park pawl ratcheting on the park lock wheel when...

It could just be a solenoid or valve body issue. I would certainly want to rule this out before moving onto more involved running gear issues e.g. reverse clutch or low & reverse clutch faults. Dexron III (now VI) is the correct fluid for the GM 5L40-E transmission. For the TD6 : “When the...