So I've read many different threads about whether or not to change the ATF in the "sealed" transmission. I'm looking for help with my particular situation.

I purchased my 04 Vanden Plas a year ago with 144,000 miles on it. I do not know whether the transmission has been serviced in any way during its history. It now has 165,000+ on it, and I'm concerned about the trans. The car runs beautifully, and I expect has many more miles and years left.

I cannot detect any problems with how the trans is working. One voice is that it's better not to open up the trans because it has such high mileage. Another voice is that the fluid must surely need to be replaced. If there's no sign of wear/malfunction at this point--why not change the ATF? or why not just leave it?

Advice? Previous experience?

Thanks,
Kenton

 

I have a 05 Vanden Plas (built Nov of 2004) with 130k on it - so essentially the same car as yours. When I bought it from the PO, I noticed the transmission was kicking a bit from when starting from a stop. At speed shifts were fine, just the 1st to 2nd gears were an issue. Also, a small leak from the trans pan seal was visible on the floor if car sat for 3 or more days in the same spot.
One garage said "the transmission fluid is good for life - ignore it" but I don't like leaks on my garage floor and the lurch on start up was a pain in the neck - literally. They flashed the TCM, and this was a slight improvement, but it still lurched.
So I took it to another place and requested the leak be fixed. They removed the pan, flushed the fluid, added new fluid, and put a new pan bottom and seal on. Car is MUCH smoother now when it comes to shifting - a big improvement. So I am happy I changed the trans fluid.

In your case, if there is no leak at all and you aren't getting rough shifts, I don't know if you should change it or wait until the pan develops a leak. In my case I'm glad I did, but I had symptoms to deal with.

Where I am in a similar boat to your issue is with the rear differential. It too is supposed to be filled with final drive lubricant 'for life' but with 130k on the car I was thinking of having the fluid in it changed as one service place recommends changing it at 120k. Then again I'm thinking 'if it isn't malfunctioning, why bother?' A debate.

 

Thanks for sharing your experience, Brent. It sounds as if getting into the transmission wasn't a problem in your case and fixed the issues you had. Sometimes I have a little lurch when stopped in 1st and stepping on the gas, but it doesn't seem too out of the ordinary. I had read that this wasn't an unusual problem with the model.

I wasn't aware of the rear differential. Something else to consider. So I'm thinking of waiting to see if any problems develop before doing anything. The local Jag dealer here said they don't do anything unless a leak develops because it's a sealed system. Right.

 

Watch this DIY YouTube video of a guy changing his ZF transmission fluid on a 03 XK8.


Three of my screws also broke and required to be drilled out.

 

I actually watched this earlier today when I was researching my issue. I think if I decide to change the fluid I'll try it myself. My local dealer wants about $800 for the job. What alternate fluid to choose if one doesn't want to go for the expensive OEM brand is another hotly debated topic.

What did your transmission service cost you, Brent? And how much of the original ATF did they actually flush? Thanks.

 

If I may add another question relating to the rear diff fluid: is there also a recommendation to change it when older than e.g. 8 years (whichever mileage) as for the ZF transmission fluid?

 

The CTSC - ZF Parts
They have a kit for oil changes.
You would expect to change around 5.5+ litres of oil.
Filling process is a little messy but easy enough.

 

Really helpful instructions and good price on the kit, especially for including the Lifeguard6 ATF. I'll probably do the flush next spring when the weather warms up unless my transmission starts acting up before then.