1999 Ranger 3.0 XLT 4x4 automatic flex fuel. Don't know if transmission is slipping, or if there is another issue underneath, but here is the scoop. Drove it last week, made a hollow moaning sound when accelerating. I recorded it so you can all hear. Let it sit a few days, drove it around and was fine. Yesterday, made the sound again, and seems to be having trouble shifting from 1st to 2nd. Almost seems to miss 2nd completely and ease its way into 3rd. No codes, no O/D light flashing. O/D can be enabled and disabled. I normally park on the down slope of a hill. When i put it into drive yesterday, there was about a 10 second delay for the transmission to engage. It is at the transmission shop now for diagnosis, I fear the worst, but at only 79,500 miles, I can't see how the transmission can be out. I inherited it from my dad when he passed away. It sat for a while with a neighbor only driving it a couple times a month to keep it running. I've had to replace the radiator, head gasket, and front ball joints/control arms. I hope to not have to sink another chunk of cash into it.

Anyone else have an issue like this? Video is attached so you can hear the sound it is making. Thanks for the responses!

 

Sounds like the flexplate is rubbing, so flexing more than it should