Raidin

Yesterday, after I changed my transmission fluid, I was told that I have my first real issue. A rear main seal leak. It's not bad, but were I to repair it, it would cost $2,000 at the dealer, and maybe a little less at my mechanic's. The dealer told me this is a 12-hour job.

My mechanic also told me this could have been caused by debris in the oil that made it past the filter. Since I run long OCIs (Oil Change Intervals, currently 26,000 miles), that may have allowed something to make it past the filter. He suggested I look into bypass filtration again. Long story short, I once looked into that to increase my OCIs but the cost difference wasn't worth the trouble. Since the filter on the bypass system is finer than the standard oil filter, it may be worthwhile just to avoid problems like this down the road.

I don't plan on fixing the leak right away, only when it's necessary. Just in case I run into another issue down the road where the transmission has to come out anyway.

nacke

Have you thought about doing used oil analysis with such a long OCI? Results would be interesting to see!

codenko

iTrader: (8)

Would def be interesting in seeing a Blackstone Labs report on the oil.

Raidin

Actually, I have. I would never go this far without making sure I can safely do it. I posted all my reports at this other forum where I discussed bypass filtration with the members. You can see my post with the 5 reports I have done so far at the following link. I posted all 5 even though each report shows all subsequent results because of the comments each report has.

https://bobistheoilguy.com/forums/ub...on#Post4222116

gshadow325

Here's another thought on the RMS.

Ever consider it is just worn out? Not because of the oci?
Ever consider a clogged pcv system? Pcv does stand for positive crank case ventilation system.
How about even changing to a thicker oil?

I ask these questions because this similar problem happened to my 4 runner with the transfer case for the all wheel drive system. I got the truck at 163000, ten years old. Did a full stage zero. Consisting of getting the car up to date on maintaince, fluids that have been neglected, hoses that look suspect and belts that are cracked.

So I changed fluids to all synthetics, immediately within 200 miles my transmission leaked and transfer case leaked.

Why? The seals held in the thick old fluid but the new thinner stuff went past it.

I drained all the fresh fluids, and changed all the seals to New ones and that was 50,000 miles ago.

On my Volvo, it's notorious for having a clogged pcv just because where the oil trap is located. That trap gone neglected loves to blow out all the seals. Ever see a oil dipstick blow out it's pretty cool.

Raidin

I didn't assume that this is due to my extended OCI. I was careful to always say that "it may be due to" or something similar. It could be just as you said, but there's no reason to ignore the fact that a bypass system can reduce the chances of something going wrong, so that reasons for problems like this are reduced.

I doubt the seal has worn out, as they tend to wear out over time, not due to miles. I can't imagine any seals are wearing out on a 2014 model. I'm going to talk to my mechanic about thicker oil, but I have to make sure it's safe on a car like the CT. I'd rather not lose the efficiency, but it may be worthwhile in the long run.

gshadow325

Well the seal should be rubber and rubber will wear out like tires. That's why I feel it might be worn out due to mileage not age. It probably very minutely worn out. Just enough for this thin oil to pass thru. Like in my case on my 4 runner. I put synthetic redline gear oil in vs the conventional Dino oil.

hypervish

Unlikely for a rear main seal. They typically leak due to age, which is not really a concern here.

Raidin

I can't imagine a seal like that wearing out like a tire would. We'd all be changing our seals every 3 or 4 years. If there's any wear, it would be from some piece of debris that made it there and rubbed against it long enough. If I ever replace it, I'll make sure to post about it. I'm curious as to what's going on, but for now, it's not bad at all so I will continue as-is.

gshadow325

Not everyone drives 300000 miles in 3 years like you. Lol. So most would be changing this out over time not over miles.

None the less, a $20 part that cost $$$$ to change out blah. I have swapped out clutches in previous cars and have always changed out the RMS. With only 100000.

nacke

Oil seems to be doing quite well despite of 2zr-fxe low oil capacity, nice.

The lip of the oil seal really wears down with miles, I think you'll notice that when you compare old one to new. I wouldn't bother to try by-pass filters, just new seals to both ends of the engine.