So goin down the road in i believe 3rd gear. Under load, if i roll on before it catches up and up shifts, or downshifts under the load there is an odd noise from the drive train. the only way i can describe it is a grumble either in the transmission or the transfer case, not a grind or anything like that just a weird audible difference. Also at the same time the tach tends to bounce a little and you can hear the rpm fluctuate in the motor. But, floor it and it doesnt skip a beat. Is this a normal occurance for a 2000 tahoe lt with 110k?