ZF Transmission fluid changes. May 2, 2019 14:28:57 GMT
Post by etypephil on May 2, 2019 14:28:57 GMT
There are two common schools of thought about this:
1) The transmission is sealed for life and the fluid does not require changing.
2) The transmission fluid has a finite life, and should be changed every 60,000 miles.
The first was confirmed to me by a chance encounter and conversation with a ZF engineer a couple of years ago, and qualified by a local transmission specialist who said that if it is working properly, it's best left alone as the fluid thickens with age / use, partly compensating for wear in the mechanism, and that changing the fluid has been known to impair operation, because the new fluid would be less viscous, and there was a risk of contamination when removing the sump, except in clinically clean conditions not usually found in workshops. However, if problems did manifest themselves, it was worth trying, as the cost is about 10% of a gearbox overhaul.
The second I can also understand, as my previous XJ transmission (never having had the fluid or filter changed as far as I know) started to misbehave, and smell of burning at around 130,000 miles. A change of fluid and sump / filter using a Bristol Transmissions kit solved the problem entirely.
More recently, there has been a spread of services such as:
offering a full transmission flush, and fluid change via the oil cooler, which does not involve removal of the sump risking contamination, has the added advantage of a 100% fluid change, which a drain and refill does not, because much fluid remains in the torque converter.
Despite what the ZF man, the transmission specialist, and Jaguar themselves have to say, the engineer in me doesn't like the idea of not renewing the fluid, ever; it seems wrong.
Does anyone have any thoughts on, or experience of the matter, particularly the idea of a non invasive flush?