The company 980A developed a crack in the filter housing. Someone with good intentions MIG welded the housing but it cracked again about 1" from the weld. I can hear you laughing. I'm told our "experts" believe the transmission is making excessive pressure. I didn't get to look at the filter housing before it was welded. I asked what was in the screen and was told there was a piece of metal, possibly a piece of gear tooth 1/2" long. I have no idea what was in the filter or what became of it. I ordered a service and parts manual and a new filter housing. I intend to disassemble and inspect any valve that could create an over pressurization before running as well as inspect the pump. I'll have a pressure gauge hooked up on initial startup. I've never heard of or seen a filter housing crack from over pressurization and am not convinced the pump can make that kind of pressure. Does anyone have any thoughts or remember a 980A with this problem. My assumption is that the crack resulted from vibration or some external force but I have nothing to support this theory. Ultimately I may find out the transmission is coming apart inside. Hours are unknown but machine should be way past expected catastrophic failure. If you have any ideas, I'm all ears. Thanks.
Need to know first where the crack was in relation to the mounting bolts and/or hose flange fixings on the housing. That could have some bearing on the problem. It's not unknown for filter housings to crack, either after a fair number of hours or after some ham-fisted mechanic has heaved on some hardware, or even stepped on it "just right". (Note to self - Do not use filter housings as a step when you're climbing down inside a machine.........) I share your suspcion about "excessive" pressure not having caused this, although if debris is flying around the system there is of course a chance that a relief valve poppet may be jammed somewhere.
I'll post a picture of the crack. It's going to take a few days. Thanks for the info.
Would have been nice to have saved the part found in the filter!:Banghead Just had a thought on the possible source of tooth. As I recall this transmission is a direct mount on the rear of engine, oil from converter is in the flywheel housing so tooth could be from a starter or flywheel ring gear problem. Any history of that kind of thing? Seems like if there was enough over pressure to crack the housing it would be causing other problems. Be very interested to see the pictures of the crack.
We have a 777F that has cracked the hydraulic filter base twice in the last 18 months or so. Machine runs fine otherwise with no alarms. We still have not got to the bottom of why it did it and have no idea whether whatever we did fixed the problem. We're treating the problem the same way as you do a Polaroid photograph - sit back and let it develop.
I'll ask about previous repairs. If I remember correctly, the finish on the starter doesn't match the block. I like that Polaroid diagnostic tool.