Had new clutches and pump installed about 2 years ago. It worked good for about 30 hours and then it started backing out the 2 top transmission bolts about every 10 hours. I can retighten and put red thread lock on them but still backs them out can't find any cracks on the frame rails anywhere. The other problem when shifting from forward to reverse either way the dozer will start to move slowly I can snatch/pop the steering handles and it will start working fine but when I shift to revers or forward the same thing. The machine will run all day just a lot of work on the snatching/popping of the steering handles. I have changed the transmission oil at least 3 times and cleaned the oil strainer which has not been stopped up. The dozer has about 80 hours on it since the new clutches and transmission pump was installed. Any information would be greatly appreciated. Dick1961
I sold my JD 450C along with the service book so I may not be of a lot of help. As for the bolts coming loose I would re torque all of them. Especially the 2 large ones on each side that bolt the frame to the rear of the engine. Which clutches were replaced? The steering clutches or the HLR transmission clutches? First I would start from scratch and check pressures in the port on top of the transmission. Then adjust linkage per the book at the transmission clutch. Then adjust the hand steering levers according to the book. Adjust the steering brakes per the book. If all that does not solve the problem then it could the clutch control rod is worn and has too much slop in it. Good luck. Sometimes it is a PITA adjusting all this because you may have to go back and forth repeating some of it to finally get it right.
Put new bolts in the transmission housing. Your threads are probably flattened and ruined. This is a known weakness of the 450C for these bolts to loosen and ruin the transmission housing.
Thanks Don k will give it a try and see if that will fix it