Strange heavy humming noise and fluctuating revs and speed.

[Stevec4012]

Hello All,

I have an S type 04 2.7d Auto with 130,000 'on the clock.

Since I have owned it (a year), I have had an issue with fluctuating revs and speed when accelerating in gear 3 and above. I had originally took it back to the dealer to fix and they couldn't (or wouldn't) find anything so they topped the transmission Oil up. This didn't rectify the problem and made my gear changes around 2½" rpm. 

Let me try and explain the noise. So say I am driving around 30mph then I accelerate to say around 50-60mph it will make a fairly noticeable vuurrm (quiet for ½" second) vuurm (quiet for ½" second) vuurm (quiet for ½" second) noise. When I take my foot off the accelerator the revs drop and rise about 500rpm. It is due into Westover Jaguar in the next couple of weeks but kind of wanted a heads up before I go in.

Also occasionally when slowing down to stop it jolts into 1st.

Any help would be greatly appreciated.

Kind regards

Steve