Hello;
I have a 2004 xj8 4.2l 120k. I got a metal trany pan and filter because it's starting to slip in 5th gear. I told a friend that I was going to change oil, pan and filter. He told me that every time he had changed oil and filter in a trany it failed shortly after. These were Chevy's not Jags.

Has anyone out there had a Jag trany fail shortly after changing oil and filter??

 

the failures were probably because, as you are, changing the oil to cure a specific problem, rather than changing it at specific intervals as a preventative measure. its not rocket science but an oil change wont cure a broken tranny. An issue in only one gear doesnt sound like something that would be cured by an oil change to me but then again you may be lucky?

 

That's an old myth, been around for decades.

 

Dealer told me the same thing. They can check the level with their computer, for $180. It requires checking level and cold and then warmed up.

 

A lot of owners have changed their own transmission oil, me included. If it were a problem there would have certainly been many posts of warning against it. Have you thought of having your transmission valves adjusted via computer? Mine was hard shifting and generally running very poorly, but was solved by having the transmission "adjusted" electronically by computer at the dealership.

 

If a dealer, or anyone, tells you that the transmission is 'sealed for life' they are wrong !

ZF, the makers of the transmission, recommend that the fluid and filter-pan are changed every 50,000 to 75,000 miles.

 

Hi DariAir,

I have been able to cure certain rough shift problems like yours in ZF 6HP26 transmissions by flushing the fluid, clearing the adaptations, and updating the firmware to the latest available in SDD v.131.03 (SDD is a Jaguar dealer-level diagnostic system). I have posted the firmware file name somewhere in the forums.

Flushing the fluid and changing the filter may improve the gearbox performance, but probably won't completely resolve the issue.

Regarding fluid, use only ZF Lifeguard 6 or Motorcraft Mercon SP. No other fluid is correct despite what the fluid manufacturers may advertise (e.g. Valvoline). Partick the Cat, Box, I and several other members have conducted extensive research on this topic and the only fluid that has been proven to have the same properties as Lifeguard 6 is Motorcraft Mercon SP (use only the Ford Motorcraft brand).

Reflashing the firmware in the transmission control module, or Mechatronic, is a risky business and requires the proper equipment and knowledge to avoid catastrophic consequences. A Jaguar dealership would be your best option, unless you have a good independent Jaguar mechanic in your area who has the necessary equipment and knowledge. To cure certain transmission issues requires a "coded access" reflash, which can only be done by a Jaguar dealer since it requires a code from Jaguar to complete the procedure.

One other thing: when you change the oil pan/filter, you should also replace the plastic electrical connector sleeve, which over time develops leaks and allows transmission fluid to contaminate the connector pins. There are plenty of posts about this on the forum.

Cheers,

Don