Discovery 4 zf 6hp26! auto gearbox leaking

[Vouge SE]

Hi All,

I'm hoping you can help me out with my current scenario and share your wisdom

I've just completed a 4500km round trip from Brisbane to Adelaide and back... The disco did the trip effortlessly and in total comfort... unlike my old TDI defender

Then next day moving the car after getting home I noticed a fair amount of oil (gearbox ATF) on the shed floor, it was relatively leak free before this trip!
It has 235000 km on it, 2010 Tdv6 with the 6 speed auto

I have pulled the little cover off into the bellhousing and it does not appear to be leaking from inside there but rather on the sides where the gearbox and motor meet. Possibly even higher up
Pictures are attached.

I have also just dropped the ATF fluid and done a change to fresh oil. (last change was about 20,000km ago) too see if that helps
Interestingly 5.5L came out but only 4L would go back in. I did follow the regular procedure for filling the auto box once at temp



Thanks!
Tony

[discorevy]

Are you sure it's ATF?, as that can be where engine oil spills over, either if someone undoes the oil filter housing too quickly, too many times and it eventually spills over or you have an engine oil leak in that area

Try having a look in the "V" to see if there is oil there.

Unusual regarding the oil quantity

Is the user name meant to be Vogue SE?

[DiscoJeffster]

Great point. Oil leak in the V from oil cooler is not uncommon and runs down the back of v the engine to the bell housing. Taste the oil. It’ll give it away. (I know my oil tastes but I can understand why you might not [emoji1787])

[Vouge SE]

Yeah its definitely ATF, I use Penrite BMV which is light brown when fresh and darkens over use.
I have had the oil over the back from an incorrectly seated oil filter before though!
It still seems to be seeping oil even when its stationary as well after i've cleaned it up with a rag

[DiscoJeffster]

Yeah its definitely ATF, I use Penrite BMV which is light brown when fresh and darkens over use.
I have had the oil over the back from an incorrectly seated oil filter before though!
It still seems to be seeping oil even when its stationary as well after i've cleaned it up with a rag

Well the mechatronic seals are known to spring a leak? [emoji2373]

[101RRS]

Well the mechatronic seals are known to spring a leak? [emoji2373]

Yes very true - I have that at the moment but that is at the rear of the gearbox - the OP indicated the oil is at the front so not so sure.

[DiscoJeffster]

Yes very true - I have that at the moment but that is at the rear of the gearbox - the OP indicated the oil is at the front so not so sure.

Great point. I can’t remember. So long ago. Thanks

[Eric SDV6SE]

Hmm, I'm with DJ on the engine oil leak, I ran BMV in the D4 for 80,000km and it never darkened, has kinda a greenish/reddish tinge.

Its hard to orient on the photos, but I reckon it may well be from the turbo oil drain pipe - known to leak due to the extreme temperatures there.

If it is the transmission, check all the pan bolts and for weeping around the gasket. Mechatronic seals do leak but the opening is at the back as said, and the seal/fixing of the seal is a tortured path, mine never leaked there, even after 220,000km.

[Vouge SE]

If it was the turbo drain pipe can that be replaced with the body still on?
I did drop the atf oil though and it looked very close if not the same, my engine oil is jet black

It also seems to keep leaking overnight after the engine is off
it pools both under the starter motor and the exhaust side of the bellhousing underneath. But does not seem to be coming from within the bellhousing with the cover off

It could be coming down from higher up possibly but im stuggling to think where from

I did just drive 4500km last week

[loanrangie]

Bmv is honey coloured so easily mistaken for engine oil and vice versa, no way for ATF to come from above so had to be engine oil.

[Vouge SE]

Possibly the oil cooler is shot, seems to be a common fault.

I’ve got my hands on an inspection camera so I’m going to have a better look this afternoon

None of this explains why I drained 5.5L of atf and could only refill 4L

[101RRS]

None of this explains why I drained 5.5L of atf and could only refill 4L

It is always good to recheck after some use and when in the required temp range - engine running, in gear etc. I bet you will have to add more.

I will pose this question just as a double check - the leak is not water from the A/C system is it?

Garry

[DiscoJeffster]

Possibly the oil cooler is shot, seems to be a common fault.

I’ve got my hands on an inspection camera so I’m going to have a better look this afternoon

None of this explains why I drained 5.5L of atf and could only refill 4L

Other than it was overfilled previously, which though it difficult. Are you sure you’ve filled it enough? Ran it through the gears etc and filled it with the engine running?

[Vouge SE]

Definitely not AC water & yep followed the refill procedure, up to temp and cycled through the gears multiple times.

I’m still of the opinion it’s atf fluid not engine oil.
I got an inspection camera in there and it is somewhat wet around the bell housing flywheel side on the inside. Not sure if it could deep in from above in there as well if it’s not the rear main seal. It is wet all over the top of the bellhousing outside but I have also had the oil filter not fitted properly in the past which spilled a large leak over the back before fixing it

[loanrangie]

Only other possibility i can think of is a blocked breather on the trans and pressure has built up and pushed fluid out the top ?

[Vouge SE]

I did have a look at the breather pipe end and it’s bone dry.

Just found a video on the 6hp26 transmission test down and it mentioned that the unit did not take any more oil after the initial fill as the transmission pump was broken.

Makes sense why I dropped 5.5L and could only refill 4L

Transmission pump must be on its last legs and leaking

[Eric SDV6SE]

Possibly the oil cooler is shot, seems to be a common fault.

I’ve got my hands on an inspection camera so I’m going to have a better look this afternoon

None of this explains why I drained 5.5L of atf and could only refill 4L

As you drain ATF, the torque converter empties as well, when you refill, you need to have the engine running so that the intergral pump inside the transmission fills the TC again. If done 'cold', thr TC does not fill up. These transmissions need to be filled at the correct level whilst the engine is running as otherwise it will be underfilled and the sump will be empty, causing air entrapment in the valve body and very poor shifting. I hope you refilled 'hot' and monitored temperature to get right fill. From memory 35deg C and atf coming out the rh fill hole.

[loanrangie]

Only half the TC is drained unless you run the engine and pump it out.

[Eric SDV6SE]

Only half the TC is drained unless you run the engine and pump it out.

True, so still you drain more than what you put back in if not running the engine.