Hello everyone,
Recently I had a customer crack the rear transmission case badly on their Cat GP30N, I stripped the transmission and replaced the rear casing, casing gasket, Orings, converter seal and drive shaft seal. Not long after going back into service the oil temp was getting hot and found that there was a cooling system leak on the engine casing overheating.
It has been in service for about a month and reported oil leaks from transmission and slow to engage drive after inspection found the converter seal leaking and drive would take 2 to 3 seconds to engage.
I removed the transmission and stripped it again and found that the drive shaft and converter seal where rock hard from being over heated (both converter and drive flange had speedy sleeves fitted on original work done). There was metal on the filter magnets and separating the pump I found considerable wear to the gear and surface faces, the friction plates and steels look fine.
I am ordering all new seals, Orings, quad rings and piston rings along with a new pump assembly and re assemble.
Can anyone think of something I may have done to cause the transmission to overheat or does anyone know if the rear casing where the filter and oil pickup passage is has any nonreturn valve.
The reason I ask that last is because the new rear casing came with a welch plug which I fitted but didn't check the old housing if there was anything in that section, I have parts exploded views that only show the welch plug.
The only other possible cause could be oil grade, if anyone has the best recommendation for these transmissions.
Thank you for any information,
Michael.