Thread: Noisy Auto

Just took the Disco for a drive and it makes the noise when warm and still makes it when stopped in neutral when you give it a rev and hold the revs. No noise at idle in neutral.

Thanx
Dave

Be careful when revving in neutral (see below)
Maybe you have a blocked filter as this can cause a high pitched whining but usually causes intermittent drive as well.


ZF Preventive Maintenance:

[Fitz Fitzgerald] There are many people putting a lot of miles on ZF transmissions, but the transmissions are more prone to failure than the AW trannys. A few words of advice for preventive maintenance on ZFs:

Do not rev the engine in Park or Neutral: this will tear one of the forward clutch packs to pieces.
Change the fluid at the specified intervals and be sure to remove and clean the pan before the first fluid change. Performing a fluid flush without first removing the pan can break up some sediment in the bottom which will be sucked up into the takeup and act like sand in the bearings and valve bodies. Feel free to toss in a larger magnet before putting the pan back on.
Run synthetic trans fluid if you can afford it. Mobil 1 full-synthetic is worth the improved longevity.


Transmission. Automatic AW70 and ZF

Thanx Mark, thats some interesting reading. I was under the impression that the ZF trans was very well built but after reading the attached documentation im not so sure.
I might drop the pan and change the filter and see if thats any better.

Dave

Hi Dave,


I think heat is the biggest killer of the ZF boxes and I cooked mine at 140k whilst towing in 40c up a big hill (fitted a P38 cooler now)


I found this interesting and must say I also noticed a drop in temp when switching to synthetic fluid.


"I have the same transmission on my Peugeot and found out that if you leave the car for a few days on with the front end on jack stands, the fluid in the converter will slowly drip out. This way you can get an almost complete drain before refilling. [Tip] HEAT is the biggest enemy of every tranny (especially in automatics). I've got a ZF on my 740 and synthetic ATF dropped the tranny temperature from 92C to 60C (driving in a summer for about 40min. in a city). I've measured the temp. on the tranny metal line, the temp. of the fluid itself is most likely higher"


Also the fluid change interval going from 30k to 120k when switching to full synthetic.

Cheers
Mark

Some more good info Mark, thanx.
Not sure if i will put synthetic fluid in it or not as I might be wasting it if it dosnt quieten down with a service.

Ive fitted one of these Aeroflow 19 ROW Engine OR Trans OIL Cooler 330mm L X 146mm H X 51mm D AF72 4019 | eBay, not sure what the temp was before I fitted it but the shift lever used to get very hot at the bottom when towing, now it is a lot cooler. Ive checked the trans cooler temp with a point n shoot type thermometer after towing and it was 62c.

Thanx
Dave

was it much effort trying to mount the new oil cooler?

Had to make a bracket and remove the bonnet safety lock. Still to refit it.

Came about because of leaking oil lines that needed replacing.

Dave