I have just replaced the transaxle (5 speed) transmission on my jd jx75 as well as a new crive belt. The xmsn pulley turns and the wheels move when the rear of the deck is lifted. But when all 4 wheels are on the ground the drive belt/pulleys turn but the mower does not self propell. Has anyone else had this problem? If so what was the remedy to the problem? Any suggetsions are greatly appreciated.