WHen i slow down and almost come to a complete stop i feel what feels like the tranny shifting into first and its almost like a thump! What does this mean? anyone have a similar issue?

 

That's the lock-up torque converter - they all do that.

 

So roger that thump is normal? ive had lower class vehicles than a jaguar and they never did that, im surprised to see that being normal for a jaguar. i appreciate the help!

 

The lockup torque converter in the ZF engages and disengages at about 55MPH, and as you come to a stop - kinda feels like a half shift or a "clunk" or "thunk". How long have you owned the car, how many miles, how often do you have your trans serviced? That ZF trans may not be the smootest auto trans but I've gotten good trouble free service out of mine (82K, 120K). They are both serviced every 30K miles.

 

i have 96000 miles and im not sure if the transmission has ever been serviced. it shifts perfectly otherwise except for that small clunk. where would be the best place to get it serviced or tuned up?

 

Your local independent shop should be able to do it for $100.00 or so. Not at all difficult AND the trans pan has a drain plug which really cuts down on the mess.

 

ok cool, i appreciate the help roger!

 

Roger is correct.

I spoke at great length with ZF down here, and they are now encouraging people with this older style 4HP24 trans to use Synthetic fluid, and introduce it one fluid change at a time. This due to the convertor "clunking" complaints that is beginning to annoy as age creeps into all the internals of the trans. It will take approx 6 drop and refills to reach a clean fluid concentration of about 90%, according to their chart, whatever. I just did it ever 3 months or so. The first was pan off and a new filter, the rest were drop and fill via the drain plug, and it is now going to get one more, then a pan off and filter swap, just to finish the task.

My 3.2ltr has 185000kms now, and I have done 5? I think drop and refills on the trans over 2 years, and the convertor is SMOOTH, and the gear change is barely detectable. It was a real "clunker" when I first got the car, really terrrible. The "old" TH400 in the V12 is also on Synthetic and way nicer than is ever was on mineral fluid.

 

Isn't cheaper do do flush-replace all at once?

 

Mmmmm, your car your choice.

I DO NOT prefer that method, and here is not the place to expand on that too much, in my opinion, other than to say that sometimes introducing a "whack" of fresh fluid reeks havoc with the transmission, either mineral or synthetic.

A couple of trans guys I associate with here are not real willing to flush a trans that is at 100k kms or more that has an unknown fluid change record, and that covers most, and only offer the introduction process I mentioned.

I have done it my way for many years, and so far I have NO failures. Some of these transmissions, mainly BW65/66 have had very SAD fluid in them, and one of my S2's had more than 500k on the same trans after I refreshed the fluid at 240k, and then anually after that, before it went to another home.

Maybe its just dumb Aussie luck, dunno, dont care, it just works and makes perfect sense to me, and time is not precious in the big scheme of Jaguar ownership.

 

Regarding the use of synthetic ATF Grant, i made the switch to synthetic ATF with my last service and noticed a positive difference in the performance of my trans right away.

 

i will definitely make the change. I have some experience with transmissions in the past with other cars and i have to side with grant on this one, a rapid change from mineral to synthetic can be devistating for a tranny. so i will make a gradual change! Thank you all!