I bought the fluid, the filter, and the gasket and set out to find a shop that would use a pump to do a complete fluid swap. Found two shops that would do it, but didn't have adaptors to fit the XK8. Found one shop that said only a Jag dealer would do it. And found one (reputable) private-owned shop that said never change the fluid in a transmission with over 100,000 miles because the fluid is full of clutch material and the new fluid detergents would cause clutches to slip. I know the worm can is open, but how many of you have changed fluid for the first time? And how many miles have you put on it since then? He services and rebuilds ZF transmissions and says ZF's are usually good for 200,000 miles before showing any problems.

 

With all due respect to a reputable(?) shop there will be many here to beg to differ with him. Just to be polite. I had 81k, though not 100k on mine and it made it even smoother shifting. I say get that crud outta there. TM

 

John,

Welcome to the forum. Lots of knowledgable people here who will chime in with their thoughts.

In my case, I just started noticing gear slippage, so did my ATF oil and filter change DIY. Not too difficult. My old ATF was dark black and smelt burnt so probably OEM so desperately needed a change. Took the opportunity, while I was in there, to install the Transgo PR valve mod. In the gearbox valve body. This fixed my problems.

Not too sure what adaptor they are referring to but maybe they are referring to software and the recommended adaptation drive to reset the software. I didn’t do that. I just followed John Dee’s advice to simply reset my ZF5HP24 transmission and just drove the car which self learnt.

While I would agree generally with your garage’s Recommendation not to mess with old auto gearboxes, what you are doing isn’t a power ATF flush! It’s simply draining the ATF in the pan. BTW you need to do this a couple of times, as the Torque converter holds ATF.

Lots of material/info on the DIY methods, if you decide to go that way. Choose the right ATF fluid. The most difficult part of the job for me was removing the corroded pan bolts. Needed an impact tool!

 

My experiences with two different ZF 6HP26 transmissions is that fresh ATF (I switched to Mercon SP with multiple drain-and-fills in both of them) is always a good decision. Most long-time owners here would probably recommend fresh ATF at least every 50,000 miles or so....

 

Agree with change fluid and filter. Mine had 117K with OEM fluid when purchased. Changed to Mercon SP with new filter, then did drain and re fill after 2-3K miles. Smooth now at 150K. Just be careful if you have the SMALL Torx head bolts rather than the Large bolts. .

 

Normally, with older consumables on a 6HP26 (the later, 4.2L cars), you would do the work from below the transmission. There are multiple steps: drain, pull the pan/filter, unlock the connector sleeve, replace the sleeve, optionally drop the valve body and replace the tube and bridge seals, put the pan back, and then do the temperature-based refill procedure, engine running. Later, you would do a drain/refill to get more of the old fluid out. Finally, you would typically do the re-set of the adaptations through the diagnostics connector. That fluid procedure through the radiator fittings does not really get you where you need to be, in my opinion.

 

My XK8 is a 4.0 with 5 speed. I understand this is a fragile transmission compared to the six speed.

 

My car is a 2000 4 liter that had 112K on it when I did a fluid change. Transmission was good going in and no problems after flud change. In fact seems to shift better. The fluid capacity of the 5 speed is 10 liters and the Jaguar specification for the ATF is LT 71141. Good luck.

 

I did fluid change as I had squawk at 95,000 miles. Changed fluid and filter, and as good as gold, that was 35,000 miles ago and still going strong.