Hey there, I'm working on a case 621 (straight 621, 1990 model with a Clark Trans) wheel loader that had a leaking torque converter. I'd spoken with a guy that had worked on them back in the day and he was pretty familiar with the issue and the procedure and said it was a pretty straight forward deal to correct, however now that I'm in the middle of it he's MIA and the procedure isn't in the manual. The machine is ex municipal and the torque converter and housing look to have been updated at some point, (I'll attach the information about what its currently got in it at the moment at the end of this) and the manual I have does not reflect this unit or how to service it, I was able to order new seals through case, but the dealer service department couldn't tell me anything about it besides a few torque values. At this point the only thing I can do is use common sense and put it back together the way it came apart with those torque values, but it would be reassuring to find some information on it somewhere period prior to reassembly so I'm not doing it twice. Any input is help full, Thanks in advance. This is what's in it: https://avspare.com/catalog/case/54670/38611/1042437/ Machine S/N is JAK0020547
When you take the thing apart pay particular attention to the sealing areas of the individual components. I don't know what kind of seals are in this particular unit, but most units I've put hands on had metal hook ring seals on the rotating elements. The rings sit in a groove on one element and ride against an internal circle of the other element. I've seen the hooks broken on the rings and the grooves worn that the rings ride in. The second item is the clearance between the impeller, stator and turbine. It's unfortunate that you don't have a book with the procedure because there is usually a specified method for measuring that. Some use a couple of ball bearings and a dial indicator. The other issue is what kind of stator, fabricated metal or cast aluminum. The steel ones have the vanes pressed between two rings and the press fits can get loose. All the impellers and turbines I've seen were cast aluminum. Look for wear marks on the three components where they fit together. There isn't much to a torque converter except all those little details that you pick up through experience.
We got it back together and (knock on wood) I'm feeling confident. The guy I had helping me was pretty knowledgeable and we basically just inspected everything, the parts all looked good, put new seals in, and reassembled it. Now that its back together I understand it a little more, its just a pain that the shop manuals I've located for it don't cover it at all. Hoping to have a day to finish it up later in the week and see if the problem is solved.