What causes the rear main seal to fail?

[jthelman]

We've been really happy with our '04 Pilot, and it has over 110K on it now.

We have had absolutely no surprise mechanical problems up until the last couple weeks. Since then, we had 2 - the front motor mount, and the rear main seal.

I've put 500k+ miles on Hondas over the last 20+ years, and never saw a rear main seal problem.

What causes the rear main on these Pilots to quit? Bad rubber? The AWD system?

I just had the seal replaced and now worry that I treated a symptom, not the original problem.

[dgipalo]

Originally Posted by jthelman

We've been really happy with our '04 Pilot, and it has over 110K on it now.

We have had absolutely no surprise mechanical problems up until the last couple weeks. Since then, we had 2 - the front motor mount, and the rear main seal.

I've put 500k+ miles on Hondas over the last 20+ years, and never saw a rear main seal problem.

What causes the rear main on these Pilots to quit? Bad rubber? The AWD system?

I just had the seal replaced and now worry that I treated a symptom, not the original problem.

What was the mode of failure? If the seal rubber was hard/cracked, then 'bad rubber' is a diagnosis. If the seal wore a groove in the crank flange, then it's not really a seal failure. Could also be that too much oil is getting on the seal or the crankcase is pressurizing - but in any case, diagnosis is in order.

[jthelman]

Originally Posted by dgipalo

What was the mode of failure? If the seal rubber was hard/cracked, then 'bad rubber' is a diagnosis. If the seal wore a groove in the crank flange, then it's not really a seal failure. Could also be that too much oil is getting on the seal or the crankcase is pressurizing - but in any case, diagnosis is in order.

From what the tech told me, it didn't sound like it cracked. He described a "sludgy" deposit around the seal, causing it to leak.

As a side note, I was going to do the job myself, but just don't have the time for something this big right now. I was astounded that the mechanic had to pull the entire engine just to separate the tranny and get at the seal. Does this sound right?

[krazykarguy]

^ How else would you get to it?

[jthelman]

Originally Posted by krazykarguy

^ How else would you get to it?

Some cars allow you to drop the tranny without removing the whole engine.

[94eg!]

I imagine you need to drop the whole front sub-frame which has the engine & transmission mounted on top of it: