3.4L Tacoma Auto Transmission

I have a 2001 Tacoma Double Cab V6 4WD truck with 297,000 miles on it. When I accelerate hard (stomp the gas), the truck shudders like it would if I was bouncing off the rev limiter except I'm not at max rpms. Also sometimes during normal driving the truck sounds like it stays in the same gear too long before upshifting. It does this with the ECT button on and off. I checked my transmission fluid and it looks suspect so I'm curious if there is anything I can do to salvage my transmission or is it toast?

I took a pic of the fluid left on a paper towel when I checked the fluid level. It's not totally burnt looking but definitely looks brown to me. I don't want to grenade my transmission by trying to fix something that can't be fixed. It is usable right now and that's fine until I can afford to buy another BUT if there is a way to salvage it I would prefer that.

 

When was it serviced last? Was it low?

 

I bought the truck used as a work/hunting truck with about 250,000 miles on it. Supposedly it was fully serviced then. I haven't messed with the transmission fluid at all since I've had it. When I checked it today the oil level was at the first notch below the hot so I'm assuming it's low now.