Hi All.
Apologies for yet another transmission issue but I have a slight whine/growl type of noise when accelerating and wonder if anyone has a theory as to the cause. It's the zf6hp gearbox with the AJV6 engine and the whine is there in all gears up to about 50mph when the engine is pulling. Ease off the gas and the noise goes away. I've changed the oil twice, renewed the filter and added some Dr Tranny but it made no difference. Gear changes are fine but I wonder if this is a prelude to something nasty happening in the future. The car has only done 47,000 miles but unfortunately most of them were in London and probably in stop start traffic.
It seems to be pointing to Torque Converter but any theories and ideas are most welcome.
Many thanks and now back to the election reports.

Pete

Is the gearbox fluid level correct?

Has the differential fluid level been checked?

Yup, Both fine. It's not a loud noise but I'm aware of it and my last xj didn't make it. I could live with it if I thought it wasn't the early stages of something nasty.

Is your air con running? Mine makes a whine that I thought was power steering related until I noticed it stopped when the ac was off. I've not figured out what it is yet because when you go and listen at the pump you cannot hear it.

It's a similar sort of whine Joe but it only comes on when the engine is pulling. I did think at first that it might be AC but sadly not.

On my old XJ, a bad transmission mount allowed the transmission to shift out of place too much during acceleration, which produced a loud whining noise.

That's exactly what it sounds like, if I just barely press the pedal it makes the noise. I'll give it a good looking at tomorrow and report back.
Thanks

It can be difficult to tell its condition just by looking at it, so try to use a prybar or something to see if you can spot movement. It was only when I removed the mount that I could see that it was totally wrecked.

Did you use OEM XF trans pan or aftermarket? If the latter you might want to swap that out. I've heard of the aftermarket pans internal filter clogging causing oil starvation.

Checked the transmission mount today and gave everything a good levering with a pry bar but all seems ok. I also looked at the engine mounts and they were fine as well.
The filter was an OEM Abonano and Lifeguard 6 fluid.
It looks like I might have to just live with it and see if it develops, although I might take it to a transmission specialist and see what they think. The noise is engine speed related and seems to disappear around 50MPH which is about the speed that the TC locks up.
Does anyone know if all X350 TCs are the same or even are all ZF6HPs the same?

Cheers

Pete

The TC's are different between the NA and SC 4.2 V8 engines. Same with the 6HP26 trans - while visually similar and will bolt up the NA and SC have a few internal differences...

Possible cause;


See also Hendrix's post on this page

The quest to find the growl continues.

Today I started the engine and as usual I could hear the Secondary Air injection compressor start up and stop after a couple of minutes, I checked the power supply to verify this . The problem is that I can still hear it grumbling away long after if was supposed to have stopped. It's a similar noise to the growl/whine that I hear when accelerating. I wonder if whatever shuts off the air flow to the exhaust manifolds is passing and allowing gasses to come back and drive the compressor like a turbine.
I wonder if I can isolate it somehow or even take the stupid thing off all together because my last car was a year older and didn't have it on at all.
Any theories or ideas most welcome.
Cheers

Pete

AHA Gotcha! ( maybe)

I took the wheel arch liner out today and listened to the secondary air injection pump start up, run for 90 seconds then stop. Only it seemed to be still making a noise but with no power going to it. I disconnected the hose leading to the shut off valve and the noise was clearly coming from there. It sounds like the growling noise that I thought was coming from the transmission. The valve is a bit of a pain to get off and entails draining the cooling system and removing a couple of hoses to gain access to the valve. The valve consists of a non return valve and a vacuum operated valve which was stuck half way. Surprisingly everything was clean with no signs of exhaust deposits on the air side. The non return seems to be working fine and my theory is that it is chattering with pulses in exhaust pressure and transmitting the noise to the pump.
I managed to free off the valve with lots of release oil and gentle taps so weather and wife permitting hope to have it back together tomorrow.
I'll report back either flushed with success or totally despondent.