First of all, I am not a believer in lifetime fluid.
We have an '08 E60 BMW W/ the ZF 6hp19(or 24?). The car has about 70k on it, I asked our dealer about a ATF change, they said it would be $1,000 and would void our warranty, but that they would do it if we really wanted to.
He explained that the fluid is a lifetime fluid, etc. I said that I did not believe in lifetime fluids and could not see any reason not to change it. He said that the fluid properties change as it ages and that the TCM compensates for these changes. He said that if you replace the fluid you have to do one of two things. One is tell the TCM to forget all learned value, the other is not do anything relative to the TCM.
He said that there are three very common failure modes for these transmissions, which is why Audi extended the warranty coverage on their vehicles with this ZF tranny.
The first is the mechatronic sleeve leaking, causing a low fluid condition and mass destruction (easy fix if caught early). The second is the mechatronic assembly (valvebody) solenoid failure, causing mass destruction in an instant with no prior signs, the third is replacing fluid and having the parameters be out of line enough that mass destruction ensues within a few thousand miles - in some cases after deleting learned values the transmission will slip and cook itself post haste.
he said the only solution is to change the fluid very regularly, or never at all.
Does anyone think there is any validity to this crazy claim of the tranny adjusting to the degrading fluid and being destroyed if new fluid is put in place? kind of a different take on the old don't ever change a high mileage ATF (which in my mind 70k is not high miles).
My inclination is to do it myself given the price, but these are kind of a pain to do. I just wanted to see if there is any validity to their claims. The tech I talked to seemed to be pretty on top of things.
'06 Infiniti G35 Sedan 6MT - 145k