Aloha,
While replacing the rear main seal on the 4.0L I discovered galling on the Main Bearings. As well as evidence of wear on the thrust bearing and crank face at the Thrust Bearing mating surface. Its clear the crank has had excessive forward pressure applied to it during some period of operation.
Over the past few years I have replaced the serpentine belt, idler pulley, Alternator and water pump due to a "chirp" originating from the belt rotation when first starting. It has happened only a handful of times during the first start of the day.
After replacement of the main bearings the crank fore and aft movement is now .0010. slightly out of factory limits, not the .0127 present at inspection of rear seal replacement.
I have heard that the transmission can over pressurize and cause excessive pressure onto the rear of the crank?
Trans oil level has never been over serviced. No cooler lines are pinched.
2004, 170,000 miles. owned since new, driven by an old guy! not trashed!
I have ordered a new radiator, thinking maybe some possible restriction? will also install additional trans oil cooler.
Can any of you Jeep Guru's shed some light on this for me?
The over pressurization makes perfect sense, the belt chirping caused by pulley misalignment when the crank was being pushed forward. The wear on the rear portion of the thrust bearing of the Crank.
Mahalo, Andrew
While replacing the rear main seal on the 4.0L I discovered galling on the Main Bearings. As well as evidence of wear on the thrust bearing and crank face at the Thrust Bearing mating surface. Its clear the crank has had excessive forward pressure applied to it during some period of operation.
Over the past few years I have replaced the serpentine belt, idler pulley, Alternator and water pump due to a "chirp" originating from the belt rotation when first starting. It has happened only a handful of times during the first start of the day.
After replacement of the main bearings the crank fore and aft movement is now .0010. slightly out of factory limits, not the .0127 present at inspection of rear seal replacement.
I have heard that the transmission can over pressurize and cause excessive pressure onto the rear of the crank?
Trans oil level has never been over serviced. No cooler lines are pinched.
2004, 170,000 miles. owned since new, driven by an old guy! not trashed!
I have ordered a new radiator, thinking maybe some possible restriction? will also install additional trans oil cooler.
Can any of you Jeep Guru's shed some light on this for me?
The over pressurization makes perfect sense, the belt chirping caused by pulley misalignment when the crank was being pushed forward. The wear on the rear portion of the thrust bearing of the Crank.
Mahalo, Andrew