Good day everyone
I have just joined and please need some help.
I have a Discovery 4 3,0TDV6

A week back i went through a mud pit and all went well, i had to help my friend with a Land Cruiser D/C V8 as he got stuck in the middle. I used a snath rope and got him out with the engine working hard.

After this episode the Battery icon came up on my instruments and on my way home which is very close about 5km restricted preformance came on.

I had it checked out and was told i need to replace my alternator, i bought one from british 4x4 and did the replacement, started the Disco and the battery light was gone. It went well for a day or two battery light still stays off, but as soon as i drive a few km’s restricted preformance comes back on and while driving when i take my foot off the gas pedal it makes this whistling noise but only when it is in restricted preformance before it goes into restricted preformance there is no sound. If I switch of the ignition and restart it is gone but comes on again after a minute or 2.

Any HELP PLEASE???