Hi

very suddenly the transmission went from appearing completely fine to slipping out of gear overnight. Car was still drivable the one day I drove it in that condition, would just rev up when changing gear and would periodically roll back on my slopped driveway when in Drive, but only a second or so before the transmission would appear to reengage, and then car would come to a halt.

Knowing that low or dirty fluid could be the cause of this (feel free to correct me if I am off the mark here) I decided to start by topping up the transmission fluid, and for the first time on a Jaguar. Reading that you could check the level by opening the filling plug, I jacked up the jack on to four axel stands. Whilst the car was tilted slightly forward when off the ground it was level side to side. An opposite to a small trickle of transmission oil from the side fill plug, and which seems to by the normal from literature on the subject when the transmission is filled to the correct level, a good litre came out.

This now poses a few questions:

1) Would having the car tilted a little forward, and given the fill plug is at the back of the transmission affected the level
2) Was the transmission some how overfilled with transmission fluid or is the literature wrong when stating just a trickle should come out the fill plug
3) When changing the fluid and refilling via the fill plug, do you need tilt the car to one side so the finished level is above the fill plug.

As always, thank full for any insight or pointers provided.

XKR 2007 190k.

 

Oh No!!!!!! You didn't say you did the top off while the engine was running! That's an absolute requirement! The fluid also needs to be at 'operating' temperature during service!
What happened is that the torque converter wasn't full of fluid and the transmission case wasn't pressurized, so all the loose fluid drained out the fill hole!

You are now VERY low of fluid!

Why did I use so many exclamation points?!!!!

 

As CeeJay implies, do not use the car until the box has been filled again as it will now be very low on fluid. There are so many threads on here about how to do with properly with the car level, the engine running and the fluid between 30 and 50 degrees C.

Richard

 

At 190k, I’m hopeful you have had a transmission fluid and filter change at least once. Twice would have been better.

As my colleagues point out, the process is specific. ZF offers these instructions as well.

 

Thank you all for your advice, and even if it not quite what I wanted to here.

Given that I have already now drained a lot of fluid out I decided to the drain the rest using the drain plug. Had a total of 4 litres come out and have today purchased 5 litres of the specified transmission fluid. Despite having reread some of the literature on refilling I just wanted to check a few things.

Firstly, and because I did not drain it correctly, is there any deviations to the normal fill process and before the torque convertor is also drain of fluid.

Once filled (and without yet running the engine) should I immediately start continue to top up the oil level once the engine is running, or something else.

Finally, given its going to take a little time to get a new tray shipped to New Zealand, and because this has not been a full flush, should I look to repeating the exercise (correctly) in a month or two and with a fresh back of transmission.

As aside and those novices like myself reading this, there does appear to be any need to lower the transmission like others have advised to access the fill cap. I simply used an allen key with a bar as opposed to a hexagon bit on a racket and extension.

Many thanks.

 

Colt,

I am attaching one of the ZF documents that gives the procedure for setting the final fluid level.

If you want to change most of the old fluid, the easiest method is to do three drain-and-fill procedures. You're already done one. After refilling with new fluid, replace the fill plug and allow the engine to continue to run for 15 minutes, periodically moving the gearshift lever to each position, Park, Reverse, Neutral, Drive, etc., holding each position at least 3 to 5 seconds.

After your third refill, you can allow the fluid temperature to rise to 30°C and remove the fill plug and allow the excess fluid to drain out. When the fluid is just a trickle and the temperature is 40°C, replace the fill plug. Do not allow the fluid temperature to exceed 50°C or you'll have to let it cool back down and start over.

If you are using an infrared thermometer to measure the fluid temperature, aim the beam at the fluid dripping from the fill hole, not at the fluid pan. The plastic pan is a poor conductor of heat so its temperature is often several degrees different than that of the fluid.

The fluids known to be correct are ZF Lifeguard 6 and Ford Motorcraft Mercon SP. The Ravenol ATF 6HP should be suitable. Don't believe the claims of Valvoline, Castrol or other third-party fluidmakers that their multi-vehicle transmission fluids "meet the correct specification for the ZF 6HP." I can easily prove to you that they do not.

Cheers,

Don

 

I would add a couple of points to Don B's comments.

Firstly, I believe that the plastic fill plug in the plastic ZF sump if not designed to be re-used. I would have sucked the old fluid out using a pump if I did not intend to replace the sump, however, we've gone beyond that now and you will have to re-use the plug. Just be careful to keep a close eye on it for a few weeks after you've done the refill to assure yourself that it is sealing properly and not working loose.

Secondly, 5 litres would not be enough to refill the box if you had removed the sump and replaced it with a new sump and integrated filter. It might be sufficient if you are re-using the sump because of the fluid trapped in the bottom of the sump and held in the filter but I think it will be marginal.

Richard

 

Just a quick note to say thank you Don and Richard for your further advice, clearly pointers and attached documentation.

Cheers.

 

ZF lifeguard is not cheap in NZ but worth sourcing some. How was the fluid in terms of smell and clarity? If it smells burnt and very black it may be a sign that your transmission has had a hard life and not enough changes in the past. Hopefully following the top-up shown above you will resolve the slipping, otherwise you may be looking at getting a replacement transmission (they are a pretty common 6hp ZF box so not too bad). There's a few rebuild shops in Auckland which might be more cost effective (haven't needed to use them though).