Loud Screeching Noise
 

I have a 98' Blazer and just had the transmission replaced recently. Not really sure if that has anything to do with it but the other day I went to take the truck for a drive when it started screeching loudly while I was driving down the road. All the electrical started dimming and it seemed like it was starting to stall. I was able to get it back home and figure out when it would start screeching. It seems to do it when I pull the shifter down between D and 3. I barely pull it out of D and down into 3 and it squeels like crazy. I've had conflicting ideas of what it could be.

Any ideas?

When the squeeling started and your electrical dimmed, this seems to point to your alternator. Remove the serpentine belt and try to reproduce the same results when your shifting.

Ok, took the serpentine belt off today and it's still producing the loud screeching noise when I pull the shifter through the gears.

Another interesting note is that I took the truck for a drive and held the shifter upwards and it did not make any noise at all. Could it be something in the steering column or could it be the transmission causing the problem?

It is leaking some kind of fluid from directly underneath the engine and it's also leaking fluid from the pumpkin ball in the rear. Might this also have something to do with it?

Any ideas?

Thought some pictures could be of assitance.

http://img22.imageshack.us/img22/5966/blazer01.jpg
http://img40.imageshack.us/img40/5755/blazer02.jpg
http://img268.imageshack.us/img268/6900/blazer03h.jpg
http://img103.imageshack.us/img103/3783/blazer04.jpg

So just lifting up on the shifter on the column makes the sound go away? I would check into the shift linkage.

I checked again just to be certain and it only does it when putting it in to or taking it out of drive. It does nothing in park, reverse, neutral, 3, 2, or 1.

Also I noticed the check engine light was on so I ran the codes and it came back with a bad O2 sensor. I also think the catalytic converter is either going bad or is bad already.

Could the cat be the cause of the loud noise?

Your leak at the rear is from the differential cover and the front appears to be from either the left valve cover, the top of the oil pan, or the oil pressure sending unit.
I've never heard of a catalytic converter making noise like you describe.

Just wanted to update my situation incase somebody else has a similar problem.

The screeching ended up coming from the alternator being triggered by a faulty neutral/safety switch. The switch had a lead wire that was broken and was shorting out.

The differential cover was replaced.

The leak from the motor was from the hoses going from the engine to radiator that cools the motor oil. Also the head gasket was bad and leaking.
After all was fixed there is no more leaking and screeching.