I have read and read, but failed to find anything that matches my exact question.

As you know I bought a 2004 4.4V8 petrol FF, and I seem to have fallen in love with it a bit-and now my Disco 4 is being repaired by the warranty co, I am in a mess deciding which to keep (or shall I keep both ).

Gearbox is smooth-really bloody smooth in every way.

But the car has an almost imperceptible vibration at pull off. That is, 1st gear at about 100-1500 rpm and the same in second. Nothing after that in any gear, No cattle grid effect at 50-60, no fluctuation in the revs when TC is locked. Its a joy to drive. Better and smoother than my Disco 4 6 speed box, that has been mega flushed and that had no issues before the flush, purely preventative maintenance. No one else can feel this!

I must point out that the cam covers are leaking and the PCV hoses are like putty and collapsed. These are being done next Wednesday, along with the oil seperater and PCV valve, so all 4 pipes and the 2 parts. I have had an engine light on for misfire on cylinder 2, which was oil in the spark plug well, which I cleaned up and reset the code with the IID. There are no codes at present and all the values for torque converter and solenoids etc look good, as are all the pressures.

Could it be the TC with those symptoms or could even the collapsed PCV hoses do it? Could it be that the spark plugs are not 100% at those revs (they are being changed next week too)? Anything else come to mind?

I will be dropping the gearbox fluid and replacing the filter at the weekend anyway, again as its good practice and knowing its done keeps me happy!

Cheers all.

Oh, and while I think about it, I was changing the oils last weekend, and there seems to be a rubber mount of some sort that the rear diff is attached to (in front of it) and that looks well worn. Could that do it?

And if anyone knows what that parts is called let me know, because that could do with being replaced anyway.

Looks like that is called a rear cross member insulator

Maybe ask Tim at Alltrack in Malvern to take a look ?? Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
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I have actually moved from Worcestershire, I will update my profile!

Anyone of you gurus any suggestions on the vibration issue?

If its a knocking noise on roll off, could be the rear transfer box. Needs examination for poss propshaft alignment fault and prob an oil change.

Thanks. No knocking at all! I have changed both diff oils and transfer case.

transfer Bearing? or the flanges deteriorating? Dunno otherwise. Sorry.

https://www.fullfatrr.com/forum/topic48232...t=transfer

You mention plugs and PCV hoses not being in the best condition.... get these replaced before delving too deep elsewhere as you could be running lean and have misfires which might manifest at that rpm range.

Deal with what you know.