I didn’t like the idea of the auto box being ‘sealed for life’ as JLR seem to state or at the very least only change the oil at a very high mileage/number of years. The official advice from ZF is that an oil and filter change should be performed at 60,000 miles or at 30,000 in arduous use. So as my L405 has just reached 60,000 I thought I had better get there and do the oil change.

Now, the first issue is that unlike the engine, when you drain the auto box oil from the sump you only are able to drain just under half the total oil. Officially this replacement of half the oil and the filter is sufficient and does count as a service, however I was keen to do more than that. I took the approach of carrying out four oil drains and refills, driving it in between each to let the oil circulate and mix. Auto transmission oil is high in detergent so the new oil does a good cleaning job.

On the fourth drain I also replaced the filter. The oil from the first and second drain was really dark, but the third and fourth looked far more close in colour to the fresh green oil. The filter pan had the usual grey paste/sludge around the magnets and in the filter.

The gear change prior to the service was fine and I had no reason to think a service was required due to the performance of the auto box, however since doing this service it is buttery smooth and changes are imperceptible. I feel it was time and money well spent as proper preventative maintenance.

I would encourage anyone else to think about having the auto box serviced and not treat it as ‘sealed for life’.

Last edited by Alex1976 on 23rd Jun 2024 8:24am. Edited 1 time in total

For anyone else thinking of doing this themselves you will need:

1. ZF 8 oil. No need to buy the genuine branded item. I bought 20l from Smith & Allan for £100.
2. Oil sump/filter. I bought a genuine ZF item for £110
3. GAP IID tool or similar as you need to be able to monitor the auto box oil temp.
4. Ramps or axle stands for safe working under the vehicle.
5. 10mm and 15mm sockets to remove the under tray to access the auto box.
6. 8mm Allen socket for the fill plug
7. 10mm Allen socket for the drain plug.
8. T40 Torx bit for the sump securing bolts.
9. A torque wrench with a low range - 2Nm to 20Nm
10. Oil pump to feed the new oil into the auto box. I used a small hand pump from Amazon.
11. A container to catch the drained oil. I used a 5 litre measuring jug as it was useful to monitor the volume and colour of the drained oil.

Or pay someone to do a megaflush! FFRR SDV8 Autobiography

Basic instructions/steps you need to carry out:

1. Put the vehicle on ramps/axle stands to provide sufficient room to work under it.
2. Remove the under tray by removing the 15mm and 10mm bolts.
3. Loosen the fill plug on the auto box using an 8mm Allen.
4. Remove the drain plug using a 10mm Allen and catch the oil in a measuring jug (it will be around 3.5 litres)
4a. If not replacing the sump, replace the drain plug and tighten to 8Nm.
5. Once the oil has drained, remove the bolts securing the sump using a T40 Torx.
6. Remove sump and use drip tray to catch last of the oil from the exposed auto box.
7. Inspect the used sump for evidence of metal and debris. Some grey sludge on the magnets is normal wear and not a sign of a problem.
8. Install the new sump using the new bolts supplied. Tighten each bolt until it contacts then tighten with a torque wrench to 10Nm using a cross bolting sequence so it evenly seats.
9. Fill the auto box with fresh oil until oil starts to dribble out of the fill port. It will take about 2 litres.
10. Start the engine and allow it to idle. Ensure the handbrake is engaged and wheel chocks etc are secure!
11. Continue to fill the auto box until oil starts to dribble out again. This will take approx a further litre.
12. Close the filler plug finger tight.
13. Get back in the vehicle and with the brakes firmly applied move the gear shifter through each of the gears, holding each for 10 seconds. Once you reach ‘D’ use the paddles to select ‘2’ and hold for 10 seconds.
14. Select ‘N’ and then increase the revs to 2,000 and hold for 30 seconds. This fills the torque converter with oil.
15. Select ‘P’ and leave to idle again.
16. Using the diagnostic tool monitor the auto box oil temp.
17. With the oil temp reading between 30*C and 50*C you can check the level of the oil again.
18. Undo the fill plug. If oil dribbles out then allow it to do so until it just drips. If no oil comes out, then fill until it does so.
19. Install new fill plug supplied the sump kit and tighten to 35Nm.
20. I like to take it for a test drive at this stage and get it up to temp (auto box oil above 70*C so it opens the oil cooler thermostat). I then recheck the level once it has cooled to between 30*C and 50*C as a final check. Or drain the oil if doing multiple flushes and return to Step 5 above.
21. Replace under tray and tighten the 15mm bolts to 60Nm and the 10mm bolts to 10Nm.
22. Remove vehicle from ramps/stands.

James W wrote:

Or pay someone to do a megaflush!

You can download the ZF service manual and procedure from their website. It has a helpful flowchart and tightening sequence, so you can't go wrong:

https://aftermarket.zf.com/app/controller/...90da53.pdf

Regarding the service kits themselves, if you plan to keep the vehicle long term, go for genuine ZF (the service is a fairly big, mucky job). If you plan to keep the vehicle only a few years, go for aftermarket fluid to save a little money. My personal view is that there's many ZF boxes done 150,000 miles on the original fluid without problem! Unlike a lot of engine oils, I do think it is worth forking out the extra for something that gets changed less frequently.

I got a genuine ZF kit with genuine sump and filter and fluid from a company in Holland for £180 delivered. 2015 Range Rover Autobiography 4.4 SDV8

Thanks for that Alex. It's next on my list of jobs. I did my X350 Jag with the 6 speed gearbox last year but it's still useful to read of someone else's thoughts and experiences.
Cheers
Pete

Quote:

ZF 8 oil. No need to buy the genuine branded item. I bought 20l from Smith & Allan for £100.

Hi all,
I have the service sheet schedule for the SDV8 L405, and the Transfer box fluid is changed every 80K Mile (or 5 years which ever comes first) and the gearbox service is at 160K miles (or 10 years which ever comes first).

Last edited by goldeneye32 on 25th Jun 2024 8:14am. Edited 1 time in total

Hi all,
I have the service sheet schedule for the SDV8 L405, and the Transfer box fluid is changed every 80K Mile (or 5 years which ever comes first) and the gearbox service is at 160K miles (or 10 years which ever comes first).
Mine is now due the 10th anniversary, although I am only at 110K miles.