This is personal opinion.. I shouldnt have to say that but I want to make it clear it's from reading about this subject a long time.

A pan drop filter change is not a flush.. and DO NOT have a flush! Unless the trans is used to having a flush.. and if your fluid on dipstick is brown, it isnt.

In fact dont change the filter.
When I did that last, it was because a chunk of concrete gashed the pan.
I was aware of folks having their trans fail shortly after. I looked up into the filter seat passage and saw gunk deposited just above the point of the seal. I found something to block the passage further up and sprayed the gunk out with WD 40.
I wondered if that gunk deposit I saw was the cause of some having problems after filter change.
And the filter wasnt even blocked all that bad despite about two tablespoons of gunk collected in pan.

So when I hear stories of folks doing the pan and filter thing then having their first -or more- problems, I think of that.
I decided that if I were going to do it again, without some other reason to drop pan, I wouldnt.. I'd just disconnect the cooling line, start engine and drain till it stopped flowing - up to two quarts - and put Lucas and fresh normal fluid in there. And six months later do the same... with Lucas in proportion to amount of fluid I was changing.

IOW, after first treatment, divide Lucas bottle by percentage of fluid replaced.

My personal experience .. I bought a 140 Kmile TBird with known hot weather slip problems, and cheap because of that. Put in Lucas and never touched fluid again, except to add a quart, and just a couple IIRC, in 150 Kmiles more.
Did it 'fix the problem? Dunno for sure because I also put a tranny cooler on. Did adding Lucas cause a problem? Obviously not.
Will say this.. no trans leaks.

 

Dont spend money for a "flush". there is a difference in a filter fluid change and flush. flush is where they flush alllllllllllll the fluid out and put in new,which in your case i wouldnt.

I WOULD drop the pan and change the filter and fluid there. I THINK its 5 quarts for yours. DO buy a bottle of lucas trans treatment. Put it in mine and my shifts are much better. Pour the lucas in it 1st,then the fluid,start with 4 quarts and lucas,then run it around the block and add as necessary until full. Dont overfill it.

 

How many miles are on the truck? Everyone I've talked to say that the fluid and filter should be changed around 100K miles. If it hasn't been changed before, I don't think it can hurt at this point.

 

There's miles and there's miles. I have had a LOT of 100K plus cars.. {value for money} and NONE of them had anything but clear fluid on the stick at that point.
The TBird I mentioned isnt clear at all but then it has 290 K on it.

Course that's just me. But if you DO change that filter, do what I did and look up in that filter passage and do what I did.. clean it but make SURE you dont spray force any deposits up into the fluid passage.

 

it has 160,000 miles

 

so don't flush it just put lucas trans fix in it

 

If the tranny fluid was brown and burnt and you didnt have alot of money try that lucas tranny fluid its an additive that mixes with your tranny fluid but that stuff has worked wonders. Unless that other guys right then you may have some serious problems. Also most of the time poeple dont either put the new rubber in or visvera and the filter just sits on the bottem of the pan anyway make sure you take your time with that tranny filter and clean the magnet off on the pan you'll see it when you get it off there. the Pan gasket is never enuff for me so I allways use a little "little" silicone the grey stuff, if I remember correctly just remember you dont want it in your tranny, you just want it to help seal up that gasket, but maybe thats just me.

 

With 160K miles on the truck, and the fluid being brown and burnt, I still stand by the fluid and filter change. And then add the Lucas stuff. Like someone said farther up, it is about 5 quarts for the fluid change ($20 approximately) and then the filter and the gasket is like $35-$40. I'm not sure how much Lucas stuff is though. Also Pettyfrog brings up a good point, make sure the fluid passage is clear so that the fluid can flow alright.

Now granted by only doing the fluid and filter change you wont get all the fluid out, only about half, but half is better than leaving that nasty brown and burnt stuff in there.

 

i am still having a hard time seeing that this is causing my problem with the high rpms

 

Because your trans isnt acting quite right and there's evidence of why. Get it acting right THEN address the TC lockup.

And my point on that passage is DO NOT dislodge any deposits in there into the fluid passage.
If you see gunk in there and dont get it out, the new filter seal may break it loose and it will get sucked and pushed into the valve body.