Recently I started hearing a strange noise coming from my trans. It happens at the high end of every gear, just before shifting and also in reverse. It's kind of like a grainy whine sound. I just had the trans flushed not even 3000 miles ago. One friend said the torque converter, another said the valve body. I'm a mechanic but have no experiance when it comes to auto transmissions. Any help is greatly appriciated.

 

Not a big fan of flushes - heard of many horror stories about the crap that gets loosened up and not entirely washed out - and the resulting havoc it wreaks.

But, what's done is done - for better or worse. Not much experience with autos myself, but suggest to first verify that the fluid is at the appropriate level and that it's clean and clear.

 

you sure its not just ground loop?

 

No idea of what a ground loop is.. And I also agree on the flush... not unless it's slipping and lucas doesn't work. But they place I bought the truck from flushed it before selling it to me. I'm more drawn towards the torque convertor as it will also make the noise when in park. Fluid is good level and clear.

 

I second this. If some old debris came loose from the flush but didn't leave the system, it may have gotten stuck somewhere and causing havoc on the front pump of the transmission, and limit the operation of the pump to properly keep line pressure up. Thus resulting in the pump whining due to low line pressure, which will cause damage and transmission failure.

 

was just out at the truck.. the whine starts at 2000 rpm and is quite noticable, as the RPMs go up it gets really loud. Once it has shifted to a higher gear and I'm running below 2000 rpm i hear nothing.

 

http://en.wikipedia.org/wiki/Ground_loop_(electricity)

 

That makes sense. Less line pressure at lower RPMs and more line pressure at higher RPMs,and if fluid is being obstructed, then there is not proper flow as the RPMs increase, resulting in a starving pump, which is the whining noise.

 

trans filter getting plugged?? Causing pump to starve??