Greeting folks, Some time ago I was throwing out questions about 642 drive chain size. I was wondering if I needed to replace the chains.....What was happening was then turning the machine, loading out of a stock pile or bank I would hear a hard bang noise which I thought was a drive chain jumping on a sprocket...After opening the machine up I removes the chains and took them to one of our local chain and bearing dealers...I was informed by then that the chains looked nearly new and that it would be a total waste of money to buy new ones...The sprockets look to be in very good condition....I purchases some half links thinking I could tighten the chains up.....I could not shorten them up at all....Soooo , it all went back together still not knowing what was causing the banging noise....Running the machine now with the , what seems like the metal to metal loud bang noise happening more frequently both while truning and digging we see the right front wheel skipping when the bang noise occurs... My question is , are there axle splines that engage with the drive sprockets? If so if this is the source of the banging when turning and digging what is the process for pulling this part of the machine apart? ? ? Also what kind of special " bobcat tools" are needed for the tear down ? Thirdly, does anyone have bearing and seal info and numbers for the 642......Thanks in advance for your help... Have fun, buckshot