ZF8 HP** Oil Service

[Procion]

This one frequently pops up elsewhere but I'm going to ask anyway as I'm non the wiser after reading so much conflicting opinion.

BMW say filled for life and there's a big green sealed for life sticker on the oil pan.
This presumably is a life of 100K miles or the factory warranty period plus perhaps, the duration of any AUC warranty thereafter.

Why do BMW say this and what do other car makers who use the ZF8 say?

ZF themselves advise a change at 40K miles if the car is used aggressively, for towing, or under heavy loads in hot climates. For "normal" use they recommend 60K.
The total capacity of the box and cooler is I believe somewhere in the region of 7 - 10 lts, model dependant if the entire system is totally drained.
It seems people report collecting around 5lt from a pan / filter change with the balance presumably remaining in the system.

If one were to change the pan & filter at 60K (Using all OEM stuff) and something goes wrong say 15,000 miles later, where would one stand warranty wise?
With only a partial fluid replacement via the pan and filter method does it make sense to subsequently change on going at 30k intervals?
Finally, if anyone reading this has had the fluid changed, what was your experience? 

Answers and thoughts on a postcard please......

 

[4aceman]

2 hours ago, Procion said:

This one frequently pops up elsewhere but I'm going to ask anyway as I'm non the wiser after reading so much conflicting opinion.

BMW say filled for life and there's a big green sealed for life sticker on the oil pan.
This presumably is a life of 100K miles or the factory warranty period plus perhaps, the duration of any AUC warranty thereafter.

Why do BMW say this and what do other car makers who use the ZF8 say?

ZF themselves advise a change at 40K miles if the car is used aggressively, for towing, or under heavy loads in hot climates. For "normal" use they recommend 60K.
The total capacity of the box and cooler is I believe somewhere in the region of 7 - 10 lts, model dependant if the entire system is totally drained.
It seems people report collecting around 5lt from a pan / filter change with the balance presumably remaining in the system.

If one were to change the pan & filter at 60K (Using all OEM stuff) and something goes wrong say 15,000 miles later, where would one stand warranty wise?
With only a partial fluid replacement via the pan and filter method does it make sense to subsequently change on going at 30k intervals?
Finally, if anyone reading this has had the fluid changed, what was your experience? 

Answers and thoughts on a postcard please......

 

I think you're overthinking this. Just change the fluid at 60k. The ZF 8s are very stout boxes but it's good to do anyway for longevity.

 

Can't speak for the 8HPs as I prefer old sh*tboxes myself, but every service I've done on a 5HP has had very good results. Shift quality improves, and there is a lot of grit in old fluid from the clutches wearing, which causes faster wear of not only the clutches, but the valves in the valve body. They fail to seal properly, and cause pressure spikes and drops throughout the gearbox.

 

How would BMW know if you've changed the fluid? And is there warranty past 60k miles?

[Liam2594]

All the time its under a BMW warranty I'd leave well alone. Likewise if you planned on extending the BMW warranty with the full cover, leave it. If you're planning on keeping the car though and its outside of warranty, I'd say it's worth replacing.