My wife and I went for a drive today and towards the end of the drive I started noticing a noise when the transmission shifted gears. It only happened a few times, and I've heard it before, but it's been infrequent. This time it happened several times in a row. At first I thought it was only happening in one gear, but it happened from 2nd to 3rd and then from 3rd to 4th.

It sounds like a whoop or a squeal, almost like a belt slipping, but slightly different. It only lasts about half a second. The pitch starts low and goes high. I park in the garage and there are no spots on the garage floor. Any advice?

It sounds like this is the infamous "bark" and, if so, it is generally noticeable on hard acceleration.

TSB S307-15 This Technical Bulletin has been issued to address customer concerns of a squeal or squeak noise heard during gearshifts under acceleration.

A 2003 XKR that I test drove once had this and my understanding it is easily fixed by a flush and refill with fluid that has some additive to address this. At least this is what I was told by a fairly knowledgeable service manager at a local dealer.

Doug

Here is the TSB. It is written for the S-type but I believe the 2003 S-type used the same ZF6HP26 trans as the XK8/XKR.

Thanks Douglas! I read the TSB, now I have a couple of questions. First, I read in another post that the transmission fluid is $100 per liter! Do I really need to use molten platinum for my transmission fluid? I mean, this is a Ford transmission, right? Second, what happens if I do nothing? I've only heard the sound infrequently, and it won't bother me as long as I know it's normal and not doing damage to the transmission. On the other hand, if the squeak is the sound of gears being ground smooth, I want to get it fixed tomorrow.

It's a ZF transmission, not a Ford. There are many discussions about alternative fluid that is identical, except the outlandish price.

I had the infamous whooping noise intermittently and the dealer injected the magic ZF additive without changing the fluid. Problem solved. I did ask if the noise indicated damage to the transmission and was assured that was not the case. The noise was more of a annoyance.

Yeah, I've been doing some searching of the forum and I came across the transmission fluid debate. What is the magic additive called? I suppose I have to buy it directly from the Jag dealership.

My '04 XK8 had the whooping sound. Fixed under warranty at 35,000 miles.

The receipt lists TSB JTB00030 and the additive PN C2C37157.
Now have about 60,000 miles and no recurrence of the problem.

Same for me on my 04 XJ8.

My transmission was also serviced under warranty with the additive. That was at 40K I know have 92K on it and I think I am starting to hear it again. Not too concerned it is due for a flush and filter change to the tune of $480.00. It is interesting to note the new fluid has either been reformulated or has the additive already in it. Hence the change of the TSB.

I went to the dealer today to get some of those little stud thingys that hold the door panel on. While I was there I asked the parts guy about the transmission fluid additive. He had to ask one of the techs, but he came back with a bottle of "ZF transmission fluid additive". Is that what I need? It was about $47 for the one liter bottle. I didn't buy it right then because I wasn't sure I wanted to do it myself. I guess I can just stick a tube of some kind into the filler hole, suck out 1 liter of fluid, and them put the one liter of the additive in, right? Any ideas on what to use to suck out the existing fluid?

I suppose you could siphon (or 'pump') using something similar to this while the tranny is cold, so nothing comes out. Then replace the exact same amount of additive.

I dunno, man! That's four dollars! Don't you know of anything cheaper? I'm not made of money. LOL!

There's a Harbor Freight just up the road in Raleigh. I think I'll go pick one up today and try this.

Make sure the amount of additive is correct (should be) but just because it comes in 1 liter bottles doesn't always mean use the entire bottle.

Well, since I recently bought the car and started to discover it day by day with reading posts here in the forum, I am hearing that bark noise in my transmissions. Actually before buying the car, I had it checked out at the private service, and they issued me a document clearly incited transmission filter needed to change due to an oil leak and the bushes at the back suspensions.

So, talking about the transmission oil filter and the fluid itself - I think to replace the filter and to change the fluid will fix the issue right ? Because I have been really annoyed by that whooping noise

Based on my personal experience, changing the fluid and filter/pan may not correct the whoop noise, it didn't for me and mine needed the additive to correct it. But others on the forum have said a fluid change did eliminate the noise for them. Jaguar discontinued the additive, but there is a new, more expensive additive to correct this now. See https://www.jaguarforums.com/forum/x...k-whoop-87351/

Yeah, I actually read all the related replies - changing the fluid seems to solve the problem. I got a quotation from the Jag service today, they charge approx. 70$ for a liter of ATF.

Thats why I think I'm going to go for the ones working fine for Jag, they mentioned about Mobil, Shell and Mercon SP.

So guys, which one do you think is a better option ?

Better option is to go to a good independent trans. shop and service it with the proper ZF fluid. The dealer will hose you if possible. I'm sure you can find the fluid and filter online for not much, and have a competent (ASA certified) mechanic do the change. Lots of cars out there have ZF trannys and they don't require liquid Jaguar gold. I did that for my 5HP24 and it went well. Changing to a different oil may not be the best way.

I have the WHOOP. The fluid additive was super expensive so I'm doing a flush and refill at 50k. The additive at the dealership was @ 150 for a small bottle!

Buy the 6 speed fluid change kit from thectsc.com. Its about $260 and has the pan/filter and 6 quarts of the correct ZF lifeguard6 fluid. Get an indie to install it. They will charge about $250-$300 to do it. Money well spent, the whooop will be greatly reduced. Changing the pan and fluid is a job for a guy with a good lift and some skills. you should also change the electronics sealing sleeve which leaks at about 60K miles and can only be changed when the pan is off. I have done this on my XKR and XJ8, both shifted and ran like new afterwards and this was 20K ago. I'm pretty sure that regular
50K changes will greatly extend the life of the tranny.