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Robbie wrote:

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1. As with all my guides this is my attempt to simplify and encourage what should be a routine maintenance task that is well within the gift of the average DIY-capable D4 owner. There may be better techniques out there so please feel free to add your own top-tips to the guide. Warning: Do not use the same oil change techniques as used on the ZF6 - the ZF8 is different.

2. Despite the extra gears available the ZF8 gearbox has far fewer components than the original ZF6 gearbox that was fitted to the D3 and early D4s. Like the ZF6 the 8-speed has proven to be an incredibly strong and reliable unit in a whole host of different premium vehicles. Unfortunately JLR has seen fit to follow the mistakes of the ZF6 by recommending that it does not need servicing before 150,000 miles or 10 years. In all regards the advice from JLR is wrong and should you follow this advice and your gearbox dies early then JLR will not lift a finger to help you. Automatic gearbox repair work is expensive and poorly gearboxes make for a miserable and uneconomic driving experience. As such it is unwise to ignore the advice from ZF and blindly follow the JLR service schedule. The fluid in an auto is used for lubrication, warming, cooling, hydraulic actuation, turbine flow, as well as a bath for the friction material and the electronics. The fluid has a hard life but with regular servicing this gearbox is capable of stella miles.

3. This guide uses my own MY13 D4 that has covered over 36,000 miles in the 3 years of my ownership. I don't tow that often and I only go off-road when I have to and not for fun. As such the gearbox and the transmission fluid have had a relatively easy life. My own intended schedule is to complete a single oil change at 36k and further changes every year after that. As the torque converter and other components retain around half the installed oil I will effectively half the age of the oil now and achieve a slow-time double flush by 50k with the minimum of expense or wasted fluid. Enough waffle - to the tools!

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4. For this job you need a set of axle stands or another method to give you a safety space, safety specs, an oil catch-pan, 10mm socket, 8mm hex, 10mm hex, ratchet, extension bar, ZF8 Lifeguard ATF (5L), plenty of shop towels and a torque wrench for the low torque values required. As ever, an impact wrench and additional lighting makes things easier. As temperature measurement is key you will also need either a suitable diagnostic tool, IR thermometer or similar. It is a good habit to measure what is removed so if you intend to do this by weight then remember to weigh your container beforehand.

5. The gearbox should be warmed-up before servicing. The vehicle must be parked in a safe location, on level ground, at off-road height or higher, safety stands positioned under the chassis rails, with the EPB applied and the gearbox in park.

6. First remove the rearmost undershield. This is secured by 5 flanged bolts with 10mm hex heads. These rust very quickly and thread into those flimsy clips, so penetrating fluid and an impact can be helpful. It does not weigh much but be careful of the hot exhaust pipes behind. With the shield removed you will see the black plastic sump of the gearbox:

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7. Towards the rear corner of the sump you will see the black plastic drain port with a 10mm socket hex fitting. Above and to the rear of it is the metal 8mm socket hex fill port plug, partly hidden by the exhaust cross-over pipe:

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8. The workshop manual calls for a special tool to remove this plug due to the lack of access. I have no idea as to why as there is loads of room around the port on mine. With the engine off and the catch-pan & rags to the ready, use a 8mm hex key on your ratchet to slowly remove the top fill port first:

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9. As the gearbox oil pump is unpowerd and the oil warm the oil level will be considerably higher than the fill port, so use the plug to regulate the flow to avoid it splashing straight off the exhaust and going everywhere. Once the flow stops use the 10mm hex key and ratchet to remove the lower drain plug. As this port is close to the exhaust you may need an extension/wobble bar or a longer hex key to avoid straining the plastic fitting. Again, use the plug to regulate the flow into your catchpan:

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10. Once the oil flow has stopped, inspect, clean and replace the drain plug. The threads on this plug will strip in a heartbeat so use a torque wrench with a low range to achieve between 8 to 10 Nm; the workshop manual recommends new plugs, but I reused the existing ones. You are now free to fill the gearbox with replacement ZF8 ATF utilising whatever kit you have to hand (bespoke oil pump, funnel and pipe, oil syringe etc).

11. First fill the gearbox until fluid starts to drip from the fill port before retuning to the driver's seat. The ZF8 needs to draw fluid to all the key components for the oil level check to be valid. Failure to follow the correct steps may damage your gearbox. The gears, clutches, torque converter and oil cooler system must all be allowed to fill:

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12. The ZF8 gearbox uses a small chain-driven vane cell pump, mounted to the rear of the TC to circulate the oil. It is a very efficient unit and places very little load on the gearbox; it too must be allowed sufficient opportunity to prime correctly:

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- Start the engine (to draw oil from the sump and pump it around the gearbox).

- With the engine still running slowly add more oil through the fill port until it starts to drip again.

Return to the driver's seat and with a firm foot on the brake and checking the EPB is still applied:

- Select Reverse for 5 seconds.

- Select Drive for 5 seconds.

- With the flappy paddle select 2nd Gear for 5 seconds.

- Select Neutral.

To fully fill the torque converter the vane cell pump must run at a higher rpm:

- Throttle to 2,000 rpm for at least 30 seconds.

- Select Park.

- Allow engine to idle normally

13. All the components of the gearbox will now be fully primed with transmission fluid, with the exception of the oil heat-exchanger system. This system is thermostatically controlled. For the oil to prime and circulate correctly the thermostat must be fully open. Using either a thermometer on the sump or a suitable diagnostic tool, monitor the gearbox oil temp until it exceeds 69 deg C. This can take a while, so you can get a brew. Temp shown on IID, bottom right value indicating 68 deg C:

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14. Having hit the magic temp I consider it good practice to repeat the gearbox selections above, but it is not called for in the workshop manual.

- Replace the fill port finger tight for now.

- Turn off engine.

15. Having primed all parts of the system correctly the final level check requires the gearbox to cool-down to below 30 deg C. Even on a cold afternoon I managed to eat my evening meal, do some other jobs and drink my first beer before it was cool enough for the level check. Having achieved below 30 deg C:

- Start engine again.

- Remove fill port plug.

- Slowly fill with ATF until a fine thread of fluid leaks from the port.

- Replace plug and torque to 35 Nm.

- Wipe area clean and inspect for leaks.

- Double check that the temperature has not exceeded 50 deg C during the filling (if it has then allow to cool and repeat the fill check).

- Turn off engine.

- Replace undershield and 5 x 10mm bolts.

- Remove catchpan, tools and the safety stands.

- Clean any spills.

- Measure or weigh the amount removed and compare with what you put in:

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16. The above gave me a fluid weight of 3.4kg which equates to around 3.9 litres. I used about 4.2 litres, albeit a small amount of this would have leaked out during the level checks. The fluid drained from my box was still green coloured and smelt normal. You do not want your oil to go anything near black as that means damage is being done. If you do have a diagnostic tool now is a good time to reset the gearbox adaptations.

17. Job done with over 4.5 litres ready for next year. I used Lifeguard 8 ATF which cost me about £50 total from the bay last year. It is a shocking price if bought direct from Land Rover.

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18. Hope this helps and remember for a healthy gearbox, change early, change often.



[With thanks to DG & geoff.]

merci
I now have the d4 SDV6 with 135k km
I do not have records, bought it at 125k changed eng lube oil n filter then and not at 135
abt to do the Auto trans oil, but using penrite at 52 Au dollars , most people use this oil as the other stuff is 300
irigged a 5l can soldered a 1/4 bsp nipple in, and fitted a 1/4 bsp valve n 10mm clear hose
I have a 2mpost hoist, but lost the use of my lefy hand so things are not easy
BTW is you do this, punch a hole in the can or you'll never get swarf out if you drill it
I used to work for CUMMINS ENG.Co as a field service and eng rebuild fitter, alas I will have to get the cam belt done by a workshop
I intend to drive to Perth next month

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, over 4000km
I worry about this car, even though it is the bestest car I have ever driven even better than my merc 500 se