What are my next steps to do?

 

I think you are getting TCC, but, aren't getting O/D.

 

Ok. What would cause it to work after replacing the t/c and why would the rpm have so much slop if the t/c is locking up?

 

its an automatic trans..... it does weird stuff. (black magic as far as I am concerned.)

Get the PCM scanned, see if there are any pending codes. Also, some trans codes won't necessarily turn on the CEL.

 

ah yes... i had the same thing happen with mine..

What fixed it for me (and from what i am told there is a TSB for it) the orifice filter in the overdrive piston housing worked loose and fell out leaving all the pressure to just bleed out and lead to no overdrive. With doing 2000 RPMs @55 mph you don't have overdrive. You should have about 2k RPMs at 70MPH.