Strange noise when hit gas

Transmission fluid level OK?

I had a 99 blazer that started making a whine after about 45000 and I drove it to about 62000 and the noise kept getting worse, transmission shop said transmission needed rebuilt at a cost of about $2000, another shop said they thought maybe it was just the pump and may last forever. I traded it in before it failed completely.

Thanks rayt333 for responding to my question. Yes the fluid level is fine. If it was the transmission, would it make the noise while idling in park? Or while I hit the gas in park or neutral? Or does that matter? I was assuming it was coming from the engine because in park, the transmission, fly wheel, and drive shaft aren't being used when accelerating. Right.I'm not sure because I know nothing about cars:[ When I had the transmission flushed about 2 weeks ago, the mechanic said that he put it on a machine and flushed it, it seemed fine and there were no clogs so the filter screen did not need replacing. Just the fluid.

I never did figure mine out, I traded it off first. But it didn't make the noise when it was idling in park or in gear, it only made noise when the engine RPM's went up, (it would make noise even when stopped when engine was revved up) but it was coming from the transmission area.