Engine Hiccups

I have a 2001 FTL Columbia with a 60 series Detroit with a Eaton Fuller 10 autoshift. The instrument cluster was changed due to gauges sticking. Went to Freightliner ordered by vin old cluster had a trans. temp gauge. It wasn't hooked up to Transmission. New cluster does not have that gauge,when due cluster was hooked up got a constant check engine light because of the gauge not being there it had a open circuit. Shop I use could not close circuit had to have Detroit Reflash ECM without that circuit. Before reflash printed everything from ECM so after Reflash we could check and make sure everything was right. Now The problem since then is on hills or inclines in 10th gear with cruise on or off I have a sudden loss of power or torque that last anywhere from1/2 to 1 second this can happen once or many times depending on hill.. Shop has checked battery box cleaned all corrosion, pulled 5 pin ECU harness found nothing wrong reinstalled. Had service techs ride with me recording and taking snapshots of it when it happens and sent to Detroit for their help. Also there is no codes at all. Could really use a helping hand here.Thanks, goloski2