Man oh man,

After reading about the chocolate "sealed for life" gearbox on the RRS and the contrary saying that the oil should/must be changed every 80'000 miles!

So, I did some google search to find out which is the best way - flush vs drain with filter change.

Some articles - from gearbox specialists say that flushing an automatic is quite risky so not a good idea. In fact, it is said that sometimes after a gearbox flush some gearboxes have failed. Apparently, this is due to deposits being forced (under pressure from the flush) into areas of the gearbox mechanism resulting in failure.

I have read that just draining the oil out from the gearbox only removes around 20%/25% of the old oil, so draining, then replacing the oil isn't that beneficial, other than changing the filter and removing tiny metal parts from the magnets in the bottom of the pan.

I also read that the latter would need to be carried out several times (over a period of a certain amount of miles) in order to benefit from having new oil.

Those who have had their gearbox oil changed - which route did you take? Or, those who haven't, what are your thoughts? RRS Supercharged Genuine HST

I've taken mine to ZF, who usually run specials on the transmission fluid change.

They have special equipment that pumps most of the oil out: the workshop guy told me about 90-95% of the old fluid comes out.

The fluid change procedure is also not straightforward: the fluid has to be heated to a specific temperature before being drained/pumped out, and the new fluid must also be put in at a specific temperature.

Not doing so will likely result in under/over-filling and will likely damage your gearbox.

take it to an expert and let them do it  --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport Supercharged V8 HSE Dynamic



Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ

from the WSM:


CAUTION: The transmission fluid level must only be checked when the temperature of the fluid is between 30 degrees and 50 degrees (ideally 40°). The fluid level obtained will be incorrect if the reading is outside this temperature range.


Adjustment

1. NOTE: Use transmission fluid meeting Land Rover specification.
Refer to: Specifications (307-01A Automatic Transmission/Transaxle - Vehicles With: 8HP70 8-Speed Automatic Transmission AWD, Specifications).

Start the engine and idle between 600 rpm and 750 rpm.
Remove the oil fill plug.
If the transmission fluid does not come out of the transmission fluid fill plug hole the transmission fluid level is insufficient. If this is the case add the transmission fluid in 0.5 liter units into the transmission fluid fill plug hole until fluid comes out.
Refit the plug.
Confirm that the transmission oil temperature is still below 30 deg C. This will ensure that the transmission is overfilled, which is necessary to prevent air suction.

Apply and hold the footbrake.
Engage Pos. R and wait 5 seconds.
Engage Pos. D and wait 5 seconds.
Tip Up to second gear and wait 5 seconds.
Engage Pos. N.

Step 1. Multiply 35 Nm by the effective length of the torque wrench (1).
Step 2. Add the effective length of the special tool (2) to the effective length of the torque wrench (1).
Step 3. Divide the total of step 1 by the total of step 2.
Step 4. Set the torque wrench to the figure arrived at in step 3.
Tighten the transmission fluid fill plug to the torque given by the calculation.

naks wrote:

I've taken mine to ZF, who usually run specials on the transmission fluid change.

They have special equipment that pumps most of the oil out: the workshop guy told me about 90-95% of the old fluid comes out.

The fluid change procedure is also not straightforward: the fluid has to be heated to a specific temperature before being drained/pumped out, and the new fluid must also be put in at a specific temperature.

Not doing so will likely result in under/over-filling and will likely damage your gearbox.

take it to an expert and let them do it

May I enquire which ZF agent you used?

ZF Cape Town, but they might be a bit far for you  --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport Supercharged V8 HSE Dynamic



Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ

I went the flush route earlier this year. This was organised by DrRob on here. I had the lowest mileage car but the oldest by age, my oil was the dirtiest. I’m glad I did a flush as whilst I had no issues it made what I thought was a smoother change even better. Anyway my train of thought that the next time it will be an oil dump and filter change and alternate it. Either way no regrets just preventative maintenance.

Steve. 2006 2.7 TDV6 HSE in Cairns Blue.

I agree with Steve  * Current: 2024 D350 Defender 90 on coils!
* Current: 1974 Lightweight 2.25L petrol. Old skool
* GONE: 2012 RR Sport HSE SDV6 Orkney Grey. Now being piloted by RRSTDV8
* GONE: 2011 4.4 TDV8 Full Fat. Amazing piece of kit.
* 1949 80" in family since 1975
I use www.glenrands.co.uk Great independent specialist!

Go for a flush and get as much of the old stuff out as you can, I also had some Dr tranny added and a reset. I wasn't having any issues but I still noticed the difference after the flush. 2010 RRS, TDV8
bali Blue / colour coded
side steps / flappy paddles
black perforated leather
22" overfinch
heated everything, TV,fridge ...... now with gold calipers and mud flaps !( black mud flaps that is) !!
Many years ago,,,,, 1955 series 1 landie , sometimes wish I had kept it

Most people on here with the zf go for a flush.

You can diy this.

Simply remove the sump plug and drain the oil
Then run the engine for about 20 seconds.
This will push the remainder out the system.

Refil with the same amount removed. So measure it
You will need to run the engine half way thru filling to get all the oil back in the level plug.
Refit level plug and switch engine off.

Filters don’t really get clogged on these and not worth the hassle of removing the sump to do it. Not straight forward

DON'T run the engine with the gearbox dry, especially the 8 speed boxes

They have a very specific TC refill procedure after dropping the oil, and running it dry will only cause more harm...

Great to know - thanks. RRS Supercharged Genuine HST

Andy K wrote:

Most people on here with the zf go for a flush.

You can diy this.

Simply remove the sump plug and drain the oil
Then run the engine for about 20 seconds.
This will push the remainder out the system.

Refil with the same amount removed. So measure it
You will need to run the engine half way thru filling to get all the oil back in the level plug.
Refit level plug and switch engine off.

Filters don’t really get clogged on these and not worth the hassle of removing the sump to do it. Not straight forward

gogsy1956 wrote:

Go for a flush and get as much of the old stuff out as you can, I also had some Dr tranny added and a reset. I wasn't having any issues but I still noticed the difference after the flush.

I have read the stories you have seen and it may well apply to some gearboxes.

To be fair 80% of ppl flushing gearboxes already have a problem.
But I’ve never heard of things getting worse. (Except when grossly over or under filled with oil).

These gearboxes don’t last so you need to do something.

Also note these gearboxes don’t use red oil.

You need oil for zf6hp

6-7 litres