This evening my wife brought the truck by work, because in her words it didn't feel right under acceleration. I looked up the codes and only found running lean Bank 2. It was both until I replaced the fuel pump. All that aside, when she went to leave she put it in drive and there was a whistling/whining noise. I immediatly thought it was a shield on the exhaust, but they were solid. She put it back in park and it went away. Tried reverse it came back. I checked the Transmission fluid and it was full as far as smelling burnt I'm lost in that department. I plan on changing out the filter and fluid in the A.M. to see if that changes anything. I'm hoping its not a Torque Converter or pump. Any ideas? Thank you in advance!

 

Before you tear into the tranny you should investigate a vacuum leak, because it sounds like one from your description. Start with the elbow at the rear of the intake that supplies the PCV system.