Quote:
Originally Posted by X5only
Where does one check/verify the spec from?
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If it is a ZF transmission (4.4/4.6/4.8) then it is either Lifeguard 5 (5 speed) or Lifeguard 6 (6 speed). BMW put their own part number on this fluid, but it is probably one of the most expensive places to purchase it. VW and others did the same, and may have it cheaper than BMW.
ZF doesn't make fluid, they just wrote, and control, the spec. ZF have a list of many oil suppliers who certify their fluid to the various ZF specs. Any one of those is fine. The confusion comes when some oil suppliers make a multipurpose transmission fluid, don't certify it, and claim that it is "suitable for applications calling for xxxx spec". ZF call for four or more different fluid specs, depending on which model transmission it is, in which vehicle, from Dexron III to Lifeguard 5/6/8, and so on. If someone is selling a fluid and saying it is good to go in all BMWs with ZF transmissions, and the GM transmissions as well, then it leads to debate about whether it is the optimum fluid, or if it is simply cheaper for them to stock only one fluid and they are driven by that factor more than the performance spec.
Note that doesn't these suppliers don't typically say they meet the spec, they say use it anyway. And it may be fine. But with all the issues associated with these transmissions, and all the debate about fluid changes, I always figured that adding another variable to the mix (non certified fluid) was just a risk not worth taking. But it is your transmission, so make your decision.