The same old 950G 5MW series we just got the hydraulics working properly on, also has a drive line noise. The machine drives well, no excessive noise while driving at speed, diff oil is clean, but when you change direction, forward to backward and vice versa, even at crawl speed, (or stationary with brakes on moving F-R lever) a quite loud deep thump emanates from the drive line. We first thought it was a uni joint or looseness along the drive shafts some where, but now we reckon we have tracked it down to excessive backlash in the rear diff. Took off the back shaft/ uni's and found there is a fairly large amount of rotation in the input shaft before you cant turn it. We believe this is where the noise is coming from when loader changes direction and this slackness in the diff gets taken up. Also some up and down movement in this input shaft (goes into the housing which sits just in front of the rear diff). Will this require a rebuild to rectify or is it possible to take this slack out without doing a major?
The only way to get the crown wheel & pinion backlash correct is to pull the diff and start from the beginning. First pinion bearing preload, then crown wheel bearing adjustment, and lastly tooth contact. It may sound trite but if there is excessive play in there how do you know you don't have the start of a bearing failure on your hands that might end up costing you a crown wheel and pinion plus a load of other bits..? Fix it now for relatively little cost or fix it later for big bucks. Also what's the S/N..? It might be a good idea to look up if it has a standard, limited slip, or NOspin rear differential in it.
Unless you can jam the crownwheel through an oil plug most of backlash is probably in the final drives . A rock in the pinion shaft should not be ignored either though .
Nige is correct. Repair it now. Later can only cost more, maybe a lot more. If the pinion shaft has *any* radial movement, you have a pinion shaft bearing preload problem, or a bearing failure.
950G rear differential slack Looks like it might be a worn yoke on rear diff. According to the plant mechanic, the backlash on both diffs is in spec, so we will check this out next week and hope to have a solution.
What I have experienced on the noise you are speaking of is excessive movement in the mounting trunnions for the rear bolster. When you get the machine back together shift the transmission from forward to reverse while watching the rear axle from the entry platform next to the cab. If it moves at all you have a big problem.