4L60 problem

Alright tranny genious's, I am having a problem with the tranny in my 93 4x4 chevy truck. Its a 4l60 tranny. It works fine in 1-2-3-R, my problem is OD. I can drive in OD but if I try to accelerate past someone or go up a hill or something the tranny begins slipping. It gets a little RPM going then engages again and goes until I need to accelerate again.

I did change the filter and found nothing significant in the fluid or filter. The fluid isn't quite the bright red it should be, but not real bad either. Before I changed the filter and after, if I pull the dipstick the fluid looks foamy.

Does this sound like a pump problem or something else? Also is a 4l60 user friendly, meaning is it something a tranny beginner could handle. I have never tore into a tranny before, so if its out of my league I will just send it in, but would prefer to save some money and do it myself.

Any advice?

Thanks, Jeff