2011 Avalanche, 5.3, 6L80, ALL stock, stock tune, 180k miles. After going WOT and letting off the gas the trans will slam hard into 4th, then 5th, then 6th (depending on speed, shifts are about 1-2 seconds apart from each other). Is there something I can adjust in the tune file? It downshifts into the correct gear going WOT without any issues, just slams into gear during the upshift after WOT only.