Help!... 04 Tacoma SR5 4x4 tranny problem?

I'm not sure if I am having a tranny problem or what it is really but here's what I have:
2004 Tacoma SR5 4x4 Automatic
180,000 miles

and here's what it is doing to the best of my observation:

in Overdrive, going up a slight grade, usually seems that it does it at low rpms(1500 to 2000) feels like it is trying to jump out of gear for a second then right back in, but if you hold it around the same rpm it will keep doing it. It's almost a jerk feeling. So I did a lil experimenting and it seems that it only does it in OD as I turned the OD off and it didn't do it but I wasn't in that low rpm range then.

 

Have you checked the trans fluid to make sure it's at the right level? If that's fine I would say the only other thing would be if one of the bands in the trans is going. You've got quite a few miles on it.

 

Ya I checked the fluid... I was afraid it could be the tranny but someone suggested to me that it could be missing to replace the plugs and wires.

 

I'm fairly sure it's gonna be something with the tranny but geuss I'll take it to the shop and see what those guys think.