700R4 making noises

[1979 GMC Sierra]

Hey guys, i have a 700R4 in my 79 GMC Sierra. Ever since i had it installed, it makes a humming/howling sound...especially when i accelerate or when it goes into overdrive. And if it's really windy or i'm climbing a hill, the humming/howling gets really loud. I've dealt with this for awhile now.

But now, another noise has appeared...a knocking/rattling sound when i accelerate fast or when it goes into overdrive. When i let off the gas, or once i'm cruising in overdrive, the knocking/rattling goes away...but comes back as soon as i give it gas. Also, if it's really windy or i'm climbing a hill, the knocking/rattling stays there and is kinda loud along with the humming.

I should also point out that the other day i found tranny fluid all over the top of the air cleaner lid. It hasn't happened since though, and i've driven it a lot.

I know i gotta get the guy who installed the 700R4 to look at it, but i'd like to see if anyone here has come across this kind of problem and knows what it is and what can be done. Any help or info would be greatly appreciated. Thanks.