Strange Fiesta MK6 problems

[NathP]

I have a 2007 Fiesta MK6 and over the past couple of weeks I have been experiencing a couple of strange problems.

When I'm driving in fifth gear I can hear a load high pitched whine noise and the faster I go it gets even more higher pitched but quieter. If I take my foot off the accelerator the noise stops completely.

When I'm driving at high speed and then slow right down for example on a slip road I can hear a loud metal rattling noise coming from under the car. This rattling noise seems to disappear once I've been driving at a constant speed for a minute or so and it only seems to happen when theres a big downward change in speed.

I'm thinking it might be a bad exhaust or bearings. Thanks for any help

 

[NathP]

Thanks for all your suggestions! The engine is a Zetec 1.4 i think

 

[NathP]

oh yeah, as for the whine on and off throttle, typically thall be gearbox or diff related.

does it make the same noise if youre foots on the clutch?

Yeah it doesn't make the whine noise when I put my foot on the clutch.

I checked my engine oil yesterday and I noticed the level was at the minimum marker so I'm gonna top it up with some Semi Synthetic 5w/30 today.

 

[NathP]

Took the car to a transmission garage today and they comfirmed that the problems are from the gearbox. They told me the gearbox oil leaked out which then caused all the damage to the gearbox, so I will need a replacement

They quoted me £700 for a replacement gearbox, oil, labour and 12 months warranty is that reasonable?