engine rattling noise

[msherman01]

I have changed the accessory belt, the belt tensioner hydrolic shock absorber, and I have this noise that sounds like a sloppy loose belt sound, but only when I'm in 2nd gear or higher, and at a low rpm. This all started out when I changed the accessory belt myself. I then started hearing this noise and asked a toyota tech about. He said it could be the belt tensioner. So now I've changed that. Is there a way I might have put the belt on wrong, causing a little extra slack? When I put it on, believe me, there didn't seem to be any extra slack. Does any one have a picture of the proper belt placement? The engine purrs nicely when at idle, and when the clutch is not enguaged, and even in first gear. This is a 2002 corola sport with a manual transmission.
Today I have confirmed that the belt is on correctly.
I purchased this car last september from a car wholesaler. Today I found out that the transmission is the problem. The bearings are the noise I'm hearing. The reason for the bearings going out so quickly is that this transmission has the wrong transmission oil inside. Some idiot has changed the transmission fluid, and used the red Dextron automatic transmission oil instead of the correct gear oil, which is much thicker. Can anyone think of why someone would intentially do this. My power and drivetrain warranty would normally have gone until 70,000 miles. This voids the warranty on the transmission. However, Toyota has said that they will still cover all parts and labor minus a $500 deductable. I guess I'm lucky to only have to pay $500, but remember that this car is new to me last september. Anyone have any idias of how to get out of paying this deductable, or how to bargain with Toyata further?