Now that I am finished with the cam chain tensioners, and replaced all of the coolant hoses, I can't stand the fact the transmission has oil in it from 1999. I see the factory does not recommend ever changing the filter or oil. WOW. I cannot find an explaination as to how the oil can last that long. I would love to know what Jaguar did to the transmission fluid so that it could maintain the properties to suspend the fibers, dirt and other items that come with use longer than any previous trans fluid. I see a description as to how to change the fluid in teh manuals. The physical side does not seem too cumbersome. I am interested in how you accomplish the recoding. Does anyone have any suggestions regarding how to accomplish the recoding process?

Thank you in advance,
Steven

Submitted by ddechant@wbhsi.net on Sun, 08/14/2011 - 12:35

Opps.. I had a senior moment. I just reviewed my dealers recommendations and he indicated changing the brake fluid and engine coolant, not the transmission fluid. Sorry for the post, I will review the material better next time.

Doug
2003 XK8 Conv

Submitted by ddechant@wbhsi.net on Sat, 08/13/2011 - 19:42

All:

I recently bought a 2003 XK8 conv. with 11,500 orginal miles. My dealer has indicated that I should change the transmission fluid as this had not been done since the car was new. As the XK8 is 8 years old I could understand that it may be time to change the transmission fluid. The XK8 is an Arizona car which does see very high temps in the summer. Does anyone have an opinion if this service is really necessary?

thanks,

Doug Dechant
2003 XK8 Conv

Submitted by salbrecht.ctc@… on Sun, 04/17/2011 - 21:36

Steve,

Thank you for the great information on the transmission.

I drained the transmission fluid several weeks ago and it came out very dark, nearly black, and smelled burnt (just like the oil of old days). In fact everyone who came over to my garage for the next hour asked what smelled so bad.

I was able to get a copy of the ZF List of Lubricants, number TE-ML 11, and on page 6 they list the 23 providers of 11B qualified fluid. In the ZF document they discuss the original filling of the transmission with the partially synthetic Esso ATF. Surprisingly the list for 11B is substantially smaller than those that meet 11A qualifications. Of course, our favorite Esso ATF LT71141 is on the 11B list. I was able to get some at $17/qt. and filled it up. I also changed the filter. Mobil provides an ATF LT71141 as well which is no surprise as Mobil and Exxon are the same company. I do not know if they are the same fluid chemically.
I
n the TE-ML 11 document ZF now recommends changing the fluid if your driving habits include "very high temperatures" which will result in "accelerated aging" of the fluid. I wonder if they found the stability of the additives within the fluid not able to suspend the particles after reaching certain temps? High temps can break down the ability of the fluid to work as effectively as intended. I have no idea if that is the case, but it could be possible. They did not elaborate.

In any case, they are recommending a change at 80,000 if high temps are a consideration, interesting.

Submitted by stevejag@sbcgl… on Sun, 04/17/2011 - 11:56

Steven,

The reason your trans has no change interval can be explained by understanding the advances in manufacturing, materials and fluid technologies. The trans fluid is a fully synthetic hydraulic oil that, unlike a petroleum based oil, does not break down, does not oxidize and does not varnish. Those 3 points are the reason earlier transmissions require some sort of change interval. The next difference is the friction material in the clutches. Historically they were made from a fibrous material. Instead, these are also made from a synthetic material that does not wear in the same way. In fact, the material that DOES wear off remains suspended in the fluid. As it was explained to me, this suspended material, even though microscopic, keeps coming back to the party and plays a roll in the operation of the clutches. So in essence, when you change the fluid, you REMOVE some of the friction material. So, every time you change the fluid, you upset the apple cart. That whole concept takes a little thought to get your head around.

That concept, too, is the reason that you don't hear of one of these boxes slipping or missing a gear usually. When they fail, it is because of a HARD failure, a part actually breaks, they don't "wear out" the clutches, as we were used to seeing when we were growing up.

Oh, on the filter, there is a non-replaceable filter in the case. I've never seen one, but I know it is there.

The "recoding" as you call it, [I think that is what BMW calls it, we call it reprogramming or reflashing] is only required on the 5HP24 when the TCM is replaced, or the trans is replaced. It requires the Jaguar diagnostic device, or one of a handful of aftermarket programming tools.

Sorry it took me so long to find this post. Hope this helps.

Cheers,