Bought this loader about 14 years ago with no 4th gear. About 10 years ago noticed bell housing bolts were loose and some missing/broken. Fixed them and all was ok . Didn't pay attention to them over the years. Now all but two or three on top are broken. And this time it's separated about 1/4" on the bottom. What would cause this? I'm hoping T.C., Bob Ont, Kshansen and the other Cat experts chime in!! We're going to pull the engine to fix the bolts but whats the cause?? We have 2 more 980B's without this issue.
As I recall the engine, torque converter and transmission are all close coupled. I would suspect the transmission trunnions on the drop box might be loose. The box would try to tilt every time the drive lines wound and unwound. You could lift the front wheels off the ground and then maybe use a big bar to pry against the drop box and frame to see if there was any movement. As I recall those mounts are also shimmed against the frame to get the center line of the drop box in the middle of the machine. Just some thoughts. Good Luck!
I think John C. is thinking right on this. I'd be checking all mounts for looseness. Don't recall ever having a 980 or it's little brother 966 that had a problem with breaking bell housing bolts. What grade bolts did you use to replace the first ones to fail? I'd also be looking at the mating surfaces if this has been run loose for some time. Hate to say it but this maybe an ongoing problem from here on out as once things get worn keeping them from moving may be a problem. Might pay to have it a standard procedure at every oil change to check for loose bolts, at least the ones you can access easy. Good luck
Thanks for the ideas. Not sure if I used grade 8's last time. I also thought about the worn surfaces. I only use it for snow so I'll check it every year.