Thread: Disco 3/4 Automatic Transmission FAQ - 6 Speed

TYK500050 TRANSMISSION FLUID 1LTR | Range Rover Sport 2005>: Transmission | shop | www.lrseries.com | L. R. Series

I bought 15 L from LR Series in the UK to do my own megaflush style gearbox service. It's cheap @ 14 pounds/L. That and a new oil pump was $500 delivered.

I will be doing (at the same time)
-megaflush
-ATF cooler (bypass radiator cooler so eliminate the glycol ingress possibility)
-Steel pan + filter

Hi all,

I hope you can welcome a Norwegian guy that needs some assistance
None on the Norwegian forum have experience with the steel sump, so hopefully someone here can assist.

I just bought the steel pan conversion kit (BMW X5 type) for the zf6hp26 and have a question related to something i found on a forum somewhere about reduced fluid capacity with the steel pan:

"Keep in mind that you are losing app. 1 liter on your transmission fluid capacity. (More frequent fluid changes required) The fluid level has to be checked with the overflow plug in the pan, not the trans housing anymore. If the filler plug in the housing is used to adjust fluid level, the trans is overfilled by app. 1 liter and will overheat-fail".

Where is the logic? It says I'll loose 1 liter but will overfill with 1 liter if I adjust fluid level with the filler plug in the housing?

Is this correct for the steel sump pan? What is the correct filler hole and fluid level check procedure?
Don't want to put this on without knowing for sure what is the correct procedure...

There is a white plastic thing attached to the top of the oil drain plug - I assume this should be there?

Thanks in advance for any help!

Even if it is true that you are adding an extra litre of sump capacity to the trans, you're hardly going to overheat it with that extra fluid. If anything it'd be the opposite. As long as you keep the fluid level to where it should be by using the fill plug and following the ZF procedure (which has been documented many times) there should be no problems.

Your information about ATF capacity seems to be incorrect. AFAIK the capacity is the same. The only difference the filtre which can be changed without undoing engone and transmission bolts or undoing the valve block. No one has had any isues with this modification that I know of. I thought the level was checked at the filler plug but not certain of that.

Yep, level checked at the filler plug with the engine on, air con on and fluid temp up to 35-40deg C.

Originally Posted by Rich84

Yep, level checked at the filler plug with the engine on, air con on and fluid temp up to 35-40deg C.

The fluid temperature is what determines the correct quantity. Cold oil at a given level could be too much oil, too hot hot at the same level, too little.

As to how you measure fluid temperature, some use those infrared thermometers aimed at the bottom of the metal pan but I think the guys with experience just go by experience - they know what is correct, and that is the tough part - getting the experience - that takes years.

As to oil quantity, I have heard of it but do not know. What I do know is the metal pan takes 21 shorter Torx screws than the plastic pan so make certain the kit has the shorter screws.

Below is a link to a number of files related to the tranny and the pan change options. A picture in one of the files shows that white plastic "wing' you refer to - and yes it should be there. If I recall correctly, it has something to do with ZF's recommended fill procedure. You use some kind of pump to get the fluid uphill and into the tranny pan thru the "drain" hole. (I think I got that right.) I also think one of the files shows that procedure.

DISCO3.CO.UK Photo Gallery - ZF 6HP26 Automatic Transmission in LR3

Originally Posted by Rich84

Yep, level checked at the filler plug with the engine on, air con on and fluid temp up to 35-40deg C.

The fluid temperature is what determines the correct quantity. Cold oil could be too much oil, too hot hot, too little.

As to how you measure fluid temperature, some use those infrared thermometers but I think the guys with experience just go by experience - they know what is correct, and that is the tough part - getting the experience - that takes years.

As to oil quantity, I have heard of it but do not know. What I do know is the metal pan takes 21 shorter Torx screws than the plastic pan so make certain the kit has the shorter screws.

Below is a link to a number of files related to the tranny and the pan change options. A picture in one of the files shows that white plastic "wing' you refer to - and yes it should be there. If I recall correctly, it has something to do with ZF's recommended fill procedure. You use some kind of pump to get the fluid uphill and into the tranny pan thru the "drain" hole. (I think I got that right.) I also think one of the files shows that procedure.

DISCO3.CO.UK Photo Gallery - ZF 6HP26 Automatic Transmission in LR3

Thanks everyone :-)

Then I will:

*Check the level by using the filler hole (temperature from my HawkEye)
*Leave the white plastic thing as it is
*Not worry about changed fluid level :-)