Rear main seal questions

Just used my tundra to pull 7700 lbs camper 375 miles to Arkansa one way then, drove another 380 miles to Durant Ok and never lost any oil.

If the rear main was bad wouldn't I lose oil while I was putting more load on the engine?

 

I assume that you believe your rear main seal is bad because you had evidence of it leaking previously, i.e an occasional drip on the driveway or an oil film on the chassis. The fact that you can't see any oil loss on the dipstick after the long tow trip does not mean that the leaking seal was healed by the driving.

My opinion is that driving a long distance towing a load doesn't necessarily accelerate a rear main seal leak, or that the oil lost would even be measurable on the dipstick. My thought is that rear main seal leaks are simply the result of wear clearance between crankshaft and the seal's elastomer lip(s). Running the engine, even under load, is unlikely to change the leak rate imo. Pressure inside the crankcase is probably slightly increased during operation, but that is offset by shaft rotation slinging the oil off before it gets to the seal. In other words, the leak is likely time-dependent rather than use-dependent.

Your rear main seal may eventually need replacement, but that repair will be expensive. In your place, I would probably adopt an attitude of "watchful waiting". If the mess it's making on the driveway bothers you enough, it may be worth the money for you to have it repaired. I have never seen a leaking rear main seal be the cause of any catastrophic engine damage, only a source of extreme annoyance.

 

Thank you and annoying it is.