Gearbox Servicing

The trend in the automotive industry (and this is not just Jaguar,
but every manufacturer) has been to increase service intervals to
reduce the cost of ownership. The issue with this is those intervals
have been proven to be detrimental to the long-term reliability
and service life of the vehicles in question. This is the case with
Jaguar's 6HP and 8HP automatic transmissions.

If you weren't aware, Jaguar does not manufacture their transmissions.
Instead, ZF are the major suppliers for automatic transmissions for Jaguar/Land Rover vehicles.
As a transmission manufacturer ZF have their own specific service instructions on how their transmissions should be maintained, and we should, and do, trust the information supplied by the companies who've engineered and developed these transmissions over the vehicle manufacturer.

ZF 6HP & 8HP Automatic Transmissions

Here at E and E Services, we have worked on ZF gearboxes for many years, who are the supplier of 6HP and 8HP transmissions to Jaguar/Land Rover. JLR rates these transmissions for a "lifetime fill," however, when speaking with the engineers at ZF who manufacture these transmissions, we've learned that the transmissions are tested to 100,000 miles with an "acceptable rate of failure" on the original fill.

Is 100,000 miles what JLR’s definition of what a "lifetime fill" is?

Or is it that most vehicles are passed the extended warranty and "good-will" repair limit meaning a failure, after that is no longer JLR's responsibility? Who knows.