I went through a filter pan and fluid change yesterday on my 2003 XK8 which went smoothly however on refill the transmission only took a little over 5 litres. The oil that came out was still a clear honey color and smelled as it should. During the refill we followed the procedure of shifting through the gears and watching the temperature as we did it. The car seemed to perform well for about the first 5 miles on a check out drive but it became reluctant to move into 6th gear unless I move it manually from D to 5 and back to D. There are no warning messages on the dash and the car is otherwise running silky smooth. I suspect that on really running the car the oil was drawn up into the torque converter and we are now low.
Does anyone have a similar experience and solution?

 

When you drained the oil none was removed from the torque converter, and the amount you put in sounds reasonable. Check the level again, making sure the transmission temp is between 30-50 deg C. I check the fluid running out the fill port with a infrared thermometer and star putting the plug back as soon as it reaches 30 C.

 

With a simple drain-and-fill, getting 5 litres of fresh ATF pumped into the system is typical. After a pan drop, getting 6.5 to 7 litres of fresh ATF pumped into the system is typical....

 

Those are symptoms of a brake switch coming out of alignment. i.e. when the trigger ratchet adjustment collapses and barely makes contact with the brake pedal stem. When that happens, the car "thinks" you have your foot on the brake and refuses to upshift. The workaround is to do that D-to-5 and then 5-to-D maneuver. Of course the brake lights should be on as well when that happens, but it is kind of hard to tell from the driver seat (my car has a small bleed of red light around the third brake light when it is on, obviously most visible at night).

The fix is to pull that ratchet back out again to make sure the switches engages when the brake pedal is at rest, no need to replace the switch.

 

I would do a hard reset with the battery and see how it goes. It needs to re adapt.
If it is the switch, then remove it from below, and change the micro switches. Radio spares do them for a few pounds.

 

Thanks for your suggestion. It's a new switch that was installed within the last 250 miles so I'm hoping it is good.

 

When you speak here or a ratchet are you talking about the cam arrangement in the brake pedal switch that operates the cruise and brake light switches?

 

I followed your advice and did a hard reset by disconnecting the battery for about 15 minutes, then took it for a 30 minute drive; the problem has gone, runs at 70 at about 1900 rpm as usual. Good advice, thanks for your input.
This forum works well.

 

I've heard many times (from owners dealers and indies) that changing ATF will cause problems. It's not a "lifetime" fluid. Changes every 50k makes sense.
If anyone has past experience with the 5 speed, I'd appreciate feedback. I've heard about "TransGo", an aftermarket pressure regulator that is supposed to lower pressure and possibly increase trans life. Any value?

 

When they told you not to change the fluid, they were probably referring to a high milage vehicle. If a vehicle has a lot of miles, and hasn't had the transmission serviced regularly, don't. This often ends with the transmission failing shortly after. Om a low mileage or a vehicle that has regularly been serviced, changing the fluid is good.

 

This is a rather old thread but I would disagree with anyone who suggests that once the fluid is beyond a certain age then it is better not to change it. There are certain methods of fluid change that I might avoid but I would certainly recommend the usual filter and fluid change through the fill/level port and, if the fluid was really old, I would change it again after a few weeks of use.

Richard

 

The 'old-fashioned' reasoning I heard for leaving REALLY OLD FLUID in the gearbox was that 'all the parts of the trans (friction material?) are 'floating around' in the fluid and draining them out will cause a failure'.
Just what I was told 50 years ago.

 

I never heard that one, Bob. I thought the filter would take them out. I can understand the reasoning behind not doing a pressure flush, but just changing the filter and fluid seems better than doing nothing.

 

I'm thinking most of these assumptions are based on the 'very' old stories of changing the engine oil with the new detergent oils. I was around then and it was true, change the old straight non detergent 30w with the new fangaled detergent type and things leaked. rattled and blew up. Oil filters got clogged and the oil passages also got clogged with chunks of thicken oil.
wj

 

GiandanielXK8 defined 'Lifetime' rather accurately as 'The day after the warranty expires'. I agree that ~50K, or even earlier, is more realistic. The reluctance of owners to do this I'm sure is in some part due to the imaginative pricing of the OEM transmission fluid.

The main pressure valve issues are pretty well documented by now. There is anecdotal evidence that they are the cause of both the 'A' drum failure and also the cracked upper valve block.
ZF recognised the problem and introduced a modified valve and 'A' drum. This (lengthy) thread in the other place is worth a read:
https://www.jaguarforum.com/threads/56718/

I did a filter/fluid change and fitted the Transgo valve at around 33K for preventative maintenance, followed later by another drain/fill to further dilute what gets left in the torque convertor. No prior issues - I just want to give the 5HP the best survival chances.

I would avoid a flush as RichardS & RJ allude, but I can see no harm in a normal drain fill.

 

It's nothing to do with the age of the fluid. It's about the lack of maintenance. Apparently you didn't read the part about if not regularly serviced. I'm a master certified automotive technician. Been working on these things for 40 years. I've done more trans services than I'd care to try to count. And seen others do more than that. I can't give an exact reason. My guess is something about the grit in the dirty fluid helping clutches get traction. If you change it out with clean fluid, the clutches start slipping. In a very short time your clutches are shot. Your transmission no go. Just like newer Ford transmissions do if you use fluid without friction enhancers Disagree all you want Do what you want I know what I've seen. Facts are what they are. Personally I'll just make sure not to get stuck with a transmission that has high miles and not serviced.

 

There is no problem with changing your fluid. It's a good thing to do about every 30k. But if you have a transmission with like 100k that's never been serviced, and you change the fluid, be prepared to need a transmission.
And wouldn't recommend a flush either. We had one of those fancy new flush machines. Sent it back after a few months. Had too many people wanting to sue us for damaging their transmission.

As for the torque converter, drain it. My 2000 XKR has a drain plug. Turn the engine and you will see it in the hole in the bottom of the bell housing. Not sure what size hex it is. I used a t30 torx. I got about 9qts out total

 

I’m with you.

My take :

the benefits of removing old and usually burnt ATF fluid are obvious. Even if you are just doing it incrementally by only draining the pan (like I’m doing) and repeating that pan drain a few times.

the drawbacks of draining the old fluid sound suspiciously like the oft repeated synthetic oil conspiracy theories. Basically, “…oh no, the sky is falling…” hysteria.

Z

 

Your XKR has a Mercedes-Benz 722.6 / W5A580 5-speed transmission, which does have a torque converter drain plug. The ZF 5HP24 5-speed in the normally-aspirated 4.0L cars and the ZF 6HP26 6-speed in the 4.2L supercharged and normally-aspirated cars do not have torque converter drain plugs.

For the 5HP transmissions the method I use for changing most of the fluid is to do two drains-and-fills, running the engine for about 15 minutes after each fill to intermix the new and old fluid, then drop the pan, replace the filter, reinstall the pan with a new gasket, and refill with new fluid and set the level per the manual. I do not like to disturb the cooler lines on the 5HP cars for fear of encouraging leaks.

For the 6HP transmissions, the same method works, but an even more thorough method is to change the fluid via the fluid cooler line ports on the side of the transmission. The line fittings are sealed with O-rings that are easily replaced, so there's little risk of creating a leak as there is with threaded compression fittings. I devised a simple apparatus using vinyl hose to connect to the cooler lines. See the How To Quick Links in the X350 forum for details.

For 6HP transmissions built prior to mid-2005, there is a firmware update available that resolves some of the harsh shift issues some of the earlier transmissions exhibited. Updating the firmware requires a high-current constant-voltage power supply and a version of SDD with the appropriate update files. I think the versions I use for this are v130.3 and v134. First the Mechatronic adaptations are cleared, then the firmware update is performed, then an adaptation drive cycle is performed.

I've heard all the horror stories about changing transmission fluid, but over 45 years of repairing all manner of vehicles, I've never experienced any of the problems others have reported. I suspect that many of the bad outcomes may have been the result of the use of incorrect fluid or incorrect fluid level.

Cheers,

Don

 

Your post said "When they told you not to change the fluid, they were probably referring to a high milage vehicle. If a vehicle has a lot of miles, and hasn't had the transmission serviced regularly, don't. This often ends with the transmission failing shortly after. Om a low mileage or a vehicle that has regularly been serviced, changing the fluid is good."

That post is all about the age of the fluid.

Whatever you've seen, you have misunderstood.

Richard