Silvrbrd

In a related problem to what has been discussed is what I am experiencing now. That is I had a Trailblazer torque converter ('04 and above) installed in my '03 GMC. I had Redline ATF put in it at the same time. Since that change I have had a problem with the PWM between 45 @ 55 mph. The torque converter locks up - about a 500 rpm drop - but after about 2-3 seconds it partially unlocks - about a 100 rpm increase. If on flat ground this starts a cycling of what appears to be the PWM causing it to partially lock, then unlock, then lock, etc. This continues as long as I am between the 45 - 55 mph range. Above 55 the cycling stops but I can't tell if it is locked or partially locked.
Another difference in before and after is lockup doesn't occur until I am 3-4 miles down the road when engine is cold. It would lock up immediately after reaching enough speed before change.
I have the Transgo shift kit sitting on my work bench but don't want to install until I have this aggravating "cycling" eliminated.
I'd like to eliminate the varible lockup completely if possible.
Any help is appreciated.
Thanks.