D17 series IV diesel rear main leak

Mattr2589

New User
After cutting a field for 2 hours or so I pulled back in the shop and noticed a steady drip every half second or so. I split the tractor and ordered a new rear main. Mine has a one piece that presses in the rear motor plate. It then has a no-ring that goes around the backside of the rear main to seal the block and oil pan. Anyway, put it back together and pulled it out. Within 5 mins it was leaking the same as before. It's dripping out of the inspection hole in the bottom of the bellhousing. It's not the transmission leaking because I can see it. I split the tractor again and pulled the flywheel. Seal looks fine and it's definitely leaking. Has anyone gotten a bad seal or have any advice. I installed the new wear sleeve so I know it's the right size. Thanks in advanced.
 
Your main bearings are shot. The crank will drop in
relation to the seal as they wear. After a while the
gap gets big enough to let oil out.
 
Well, I'm not thinking main bearings just yet. You say you replaced the rear main seal. Did you remove the old steel wear sleeve off of the flywheel nose and install a new steel wear sleeve??? It has to be there and it will surely leak if it isn't.
 
i did replace the wear sleeve. I am going to pull the rear cover back off and check the play in the crank. That was the only other thing I could think of. I figured if the mains were wore out bad enough for it to leak then surely it would be knocking. Anyway, I will check it later and let y'all know. Thanks.
 
Your main bearings are shot. The crank will drop in
relation to the seal as they wear. After a while the
gap gets big enough to let oil out.
 
So, I pulled the rear plate off to check for play in the crankshaft. When I did it dumped a quart or two of oil on the ground. The first time I removed the rear plate I didn't lose any oil. The oil is very thin and runny. Seems like it has a bunch of diesel fuel mixed with it. I just had the head repaired for cracks between the valve seats. If the oil is over filled and too thin, I guess this could cause it to leak. Any known concerns for diesel in the oil?
 
(quoted from post at 09:42:46 07/19/15) So, I pulled the rear plate off to check for play in the crankshaft. When I did it dumped a quart or two of oil on the ground. The first time I removed the rear plate I didn't lose any oil. The oil is very thin and runny. Seems like it has a bunch of diesel fuel mixed with it. I just had the head repaired for cracks between the valve seats. If the oil is over filled and too thin, I guess this could cause it to leak. Any known concerns for diesel in the oil?
Umbrella seals on the injection pump driveshaft.
 
(quoted from post at 10:55:28 07/19/15)
(quoted from post at 09:42:46 07/19/15) So, I pulled the rear plate off to check for play in the crankshaft. When I did it dumped a quart or two of oil on the ground. The first time I removed the rear plate I didn't lose any oil. The oil is very thin and runny. Seems like it has a bunch of diesel fuel mixed with it. I just had the head repaired for cracks between the valve seats. If the oil is over filled and too thin, I guess this could cause it to leak. Any known concerns for diesel in the oil?
Umbrella seals on the injection pump driveshaft.


Could this be why it's leaking oil?
 
If the umbrella seals are leaking on the injection pump drive shaft AND overfilling the crankcase with diesel fuel, it sure could contribute to a leaking rear main oil seal. Regardless, if it is overfull of diesel fuel in the engine oil, you must correct that problem, rear seal leaking or not.
 
(quoted from post at 14:26:16 07/19/15) If the umbrella seals are leaking on the injection pump drive shaft AND overfilling the crankcase with diesel fuel, it sure could contribute to a leaking rear main oil seal. Regardless, if it is overfull of diesel fuel in the engine oil, you must correct that problem, rear seal leaking or not.
Is this something I can do or do I need to send the pump off? I am a mechanic.
 
Sorry I didn't mean to post twice.main bearings wont cause a knock until they spin and cut off oil to the rod and cause it to spin. That said I agree that if it is over full I'd address that first and the umbrella seal is the most likely culprit if they use a pump like a 190. Not sure on that one.
 

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