I'm getting a strange noise when accelerating slowly with the transmission in 3rd gear around the 2200 rpm mark. It shifts and drives fine, no slipping or lurching or any of that jazz. I've read up on the "ZF squawk" but that seems to refer to harder acceleration and downshifting particularly from 6th to 4th gear; although the sound could best be described as a squawk type noise and it definitely sounds like it is coming from the transmission (almost sounds like a New Year's Eve party horn or kazoo). It doesn't do it in any other gear, and is a little inconsistent, but a lot more often when the transmission is cold. I changed the fluid about 10k miles ago, but with all the hard driving I do I am probably going to change it again anyways but thought I'd see if anyone had any input or a similar experience first.

 

Is the noise more of a buzz and does it turn on as turn off at random?

 

Does it go away when the transmission warms up?

On my 2005 STR the transmission was totally quiet until I had the fluid changed. As you know Jaguar released a special additive to quiet this noise. Then the additive was discontinued and supposedly was in the regular Lifeguard fluid. So I could not find the additive and just had the change done with Lifeguard fluid.

Now I have read there is another magic additive you can get. I may have fallen in the middle and used Lifeguard fluid that was made before the additive was included. So I am considering getting the fluid changed again with the hope I can get lifeguard fluid with the noise additive in it.
.
.
.

 

It could be described as a buzz, and it is intermittent but typically at the specific RPM and gear I described.

It didn't go away until the transmission got up to or close to full temp (I'm guessing as I don't have a transmission temperature gauge). I had been driving for at least 20 minutes before it seemed to go away.

My first plan of action was going to be to change the fluid and filter again because as pricey as it is, its still the least expensive option.

 

Sounds like a variation of the infamous "ZF squawk" to me....

My 2005 S-Type 3.0 (currently just under 82,000 miles with the factory fill of Lifeguard 6) occasionally squawks on upshifts, but only during the hot summer months. Haven't heard a squawk for at least six months now. Back in December I had the two infamous weeping transmission oil cooler lines replaced. After the new lines were in and torqued down properly, right at 1.5 litres of fresh Lifeguard 6 were required to bring the ATF fluid level back up to full. So it will be interesting to see (and hear) if that small amount of fresh ATF will silence the squawk come summertime....

My wife's 2006 XK8 also began squawking occasionally early last summer (also on upshifts) at about 64,000 miles with its factory fill of Lifeguard 6, but the sound was remarkably different compared to my S-Type's squawk. The XK8 squawk sounded like a muffled squeak from opening a screen door with rusty hinges. The S-Type squawk sounded like a single yap from a small lapdog. Same ZF 6HP26 transmissions, same ATF, but very different sounds. Rick and I did a ZF drain-and-fill in mid-July on the XK8 including a new pan, a new sleeve, and right at 6 litres of fresh Lifeguard 6. According to my wife, her XK8 hasn't squawked since (she crossed 77,000 miles this morning)....

The moral of the story is that perhaps no two ZF squawks sound alike. What ATF did you use during your drain-and-fill 10,000 miles ago?

 

It had to have been LG6. I changed the filter and electrical sleeve at the same time. I think I will have to do it again with the additive tbird6 mentioned. I may have a transmission cooler line starting to leak a little, but its pretty minor (more seepage than a leak) and wouldn't be enough to cause a low fluid level. All this started happening a couple days ago.

 

You would be surprised at how much ATF can weep out of those rubber hose-to-metal tube joints in the transmission oil cooler lines. I didn't believe I had lost much ATF, either. Turns out I was down 1.5 liters. Discovered the weeping lines in late September. The new lines were installed in mid-December....

Keep a close eye on your potentially-weeping lines. These leaks get larger as time passes. I'm told that the ZF 6HP26 box can degrade rather quickly once it loses more than 2 litres of ATF (capacity is 10 litres). The less ATF in the pan, the quicker the heat cooks and degrades the ATF that remains....

 

Hmmm...maybe I will replace the lines at the same time then. I will do a fluid check before I touch anything else and see if I am indeed quite a bit low on fluid. I would think that I would be getting a more consistent symptom, but maybe this is more of a warning symptom as a sign of things to come if I don't act.

 

I think that's a good plan. Keep us posted on what you discover....

 

Poked around a bit, found the rubber flywheel inspection cover rubbing the flywheel, but that didn't cure the noise and the fluid level was good. It seems the car is making the noise in 1st and 2nd gear as well, but most (and very) noticeable in 3rd. If I put it in 4th the noise ceases. I ordered more fluid to drain and fill it again, and if that doesn't work then I will try the $150/quart miracle additive.

 

If a drain-and-fill of fresh ATF does not cure your issue, I don't believe the miracle additive will, either. The additive is for those folks who want to try to cure their issue without doing a complete drain-and-fill....

 

Finally got some time to change the fluid and filter today (only had 3 days off work total the last 4 weeks). It was definitely burnt/smelled and there were a lot of air bubbles under the filter. The track has not been so kind to my transmission fluid. However, both magnets in the pan were clean and I didn't see metal shavings of any sort when draining it. I didn't hear the noise afterwards, but since it was inconsistent before, I will have to drive it a few more times without hearing it before I consider it cured.

 

Hope it cures your issues. What ATF did you choose?

 

Lifeguard 6. Wasn't aware of any other real options. Drove it a couple more times today, not a peep so I am very optimistic that it was just aerated fluid.

 

Well, I got it resolved. It turned out it wasn't the transmission at all. I thought I started hearing the noise again, but not as loud. I found a metal bracket that runs across the exhaust right behind the transmission, and it turns out the exhaust was hitting the bracket and causing the exhaust to make an odd buzzing noise (strangely, almost exclusively in 3rd gear) further up towards my x-pipe and echoing up the transmission bell housing (the noise sounded like it was coming directly out of the J-gate). I removed the bracket, and now the noise is completely gone as well as some other annoying (mostly intermittent) buzzes and rattles. I will be putting the bracket back on with a couple of washers so it sits a few mm lower and won't touch the exhaust. Keep in mind my exhaust has been hacked up a few times, so I wouldn't expect this problem on a stock STR.