Drive Train Help!

Newbie to the Mustang circuit and I will be the first to admit my knowledge of cars is limited -but I am learning!!

Questions I hope one of you fanatics can help me with.

1) Rear end has been redone - 3.73 gears plus new racing clutch (not sure which brand). There is a whining coming from the rear end especially in 4th. I was told this may be a throwout bearing?? Anyone have any idea if this is right? I haven't taken it anywhere yet but like I said I want to learn about this stuff myself and not always take it somewhere.

2) When sitting idle (in 1st gear & clutch in) the car acts like the trans. is still engaged. What I mean is if you give it gas in the above position it inches forward. I am guessing this is a clutch adjustment problem???

Any help is welcome and appreciated.

Is there anything I can do to get rid of the whine?

Any ideas on the clutch problem or just have it adjusted?

I probably will check the fluid come spring when I can get at the car again easily - its away for the winter.

The clutch is definately aftermarket and I think my friend had an issue with it originally and had it replaced again inkind. I have all the paperwork on it so will look to see what brand - no grinding when shifting and clutch seems to engage normally (to me anyway - not low or real high - not sure how to answer that) from all the other standards I have ever driven.

I bought the car this past August kind of a last minute thing with a friend who moved and had to get rid of it. It was garaged for 3 1/2 years so I know there are things that will need replacing.

Thanks for the advice and will definately check into the things you all mentioned.