Rear main seal worth replacing?

I have a 2004 Tacoma automatic with the 3.4L. It's got 227K miles and I have a pretty bad rear main seal leak. I first noticed it a few months ago as a few drips on the driveway, but over the months it's now turned into a small puddle under the truck every morning. I have no problem just living with it and throwing oil in it every once in a while, but many people have told me that's it's possible that the seal could break while driving and pour all my oil out onto the road. Has this ever happened to anyone? Also I have been to many different mechanics who have all given me quotes saying it will be anywhere from $600-$900 to replace the seal . However, 2 of them have said that replacing the seal is not even worth it because if there is any play in the crankshaft then the new seal will just begin to leak again and the only way to fix this is an engine replacement or rebuild. I'm just hoping to get some clear answers before I make my decision. Thanks.

 

Not that expensive if you do it yourself however it takes a lot of time and some knowledge to do it right. I mean the seal is less than 20 bucks. Plus oil for your trans and engine. What they are quoting you for mainly is labor.

I doubt there's any play in the crank like that. My taco granted a 2.7 has over 300k and the rear main is still good. The labor required is over 6 hours to do the job for 1 person. I've very rarely heard of a crank having that much play to where it won't seal on these.

I think it's worth doing the seal and do some "while you're in there" checks and work. Those motors run a long time. 200k isn't unheard of. Plus it's piece of mind. You can get another one of those motors for fairly cheap but the labor to install will be much higher. Additionally you don't know what shape that motor will be in.

Get the seal done before it gets worse. Go to a place with good reviews and fair pricing.

My 2 cents

 

Thank you that helps a ton. I would definitely do the job my myself, but the problem is that I don't have enough space in my garage to pull a trans. Also I'm not sure if I trust myself doing it. Also what do mean when you say "while you're in there" checks. What else exactly should be checked when in there?

 

The seal won't suddenly fail! It may gradually get worse. You can also buy "Oil stop leak" I've never used it. It's supposed to swell the seals. But it could swell all the oil seals on the engine.
Check engine compression before you pull the motor. This would give you an idea of engine life.
Your options are;

Do a light rebuild. Rings, rod & main bearings, water pump,timing belt & oil pump.
Leave it alone and just replace the gaskets & seals that are leaking.


If you pull the engine or trans to fix the seal.
"While you're there"

Change the rear pilot bearing in the crankshaft. (manual transmissions)
Rear seal on transmission.
Clean off the firewall while the lump is out of the way.


Check the following;
Check "U" joints on driveshaft.
Check ring gear teeth.
Possibly change A/T fluid & filter.
Check-Speedometer gear seal.
Check for leaking valve cover gaskets.
Replace Spark plugs.
Check Oil pan gasket.

 

Don't do any stop leak, not worth clogging your engine over.

@Timmah! has a video, 3 parts to it, on how to replace a transmission. You'll need it to remove and bolt back on.

 

You'll want to get a transmission jack, either buy one or rent one. Muscle-ing the transmission in and out is a royal PITA.

 

So at 227K you don't think there could be play in the crankshaft causing the rear main seal to leak?

 

If you are need of a new clutch, just get all that done while the shop is in there, that way you aren't spending a ton on labor. Hit two birds with one stone.
(this is if you have a shop do it)

 

Are you sure it's the main seal, and not a valve cover leaking?

My 307k mile Tacoma has never leaked oil, except for the at the valve covers. Usually re-torquing the valve cover bolts stops the leak. Just saying.

 

Some pictures...

 

It's a Toyota, not grand pappy's Chevy which end crankshaft end play at 500 miles.

 

Manual or automatic?

While it may well be the rear main, don't rule out valve cover contributions as others suggest. Think about where the back edge of the cover would leak / drip. Could be both of them leaking (VCs and Rear main)

You can degrease the area and monitor to see how long it takes to get messy again too.

How often are you adding how much oil?

And don't bother returning to the mechanics with the crank play scare stuff. While it's a true statement, they aren't too in-touch with Toyota motors. And going along with that concept, is the front seal badly leaking?

 

I have a 2001 4Runner 3.4 Auto 4X4 and the rear main seal blew on the interstate while my GF was driving. She pulled over immediately after seeing the smoke from the oil hitting the exhaust. Saved the motor...we had it towed to the mechanic and they replaced the rear main and front transmission seal. Truck had 290,000 on it at the time. Now has 306,000 on it with no leaks. Definitely worth replacing.

 

yank your transmission. its honestly not that bad a job. i watched a ton of videos, read all the walkthroughs. my clutch was boned so i replaced it at same time. if automatic its still just as doable. just a few extra steps. a weekend in the driveway with a few floor jacks or a few good strong buddies. much easier to do if 2wd. 4wd (mine) was a pain in the ass due to the transfer case and havinf to disconnect one extra driveshaft and all that. but overall it CAN be done and its not the end of the world

before any of this please do yourself the favor and hose down the rear sections of the valve covers and any other oil surface with brake cleaner. i used like 5 or 6 cans. VENTILATION IS KEY. NO SMOKING lol. clean it all off and drive it for a day. see where its leaking. it may not be the rear main seal at all

 

Don't even attempt to do this job without a transmission jack. It will never line up with the dowel pins if you didn't have the up/down side to side adjustments that the nicer tranny jacks offer.

I replaced my rear main seal on my 2.7l at 92,285 miles when I did my 4WD PreRunner swap. Really not that bad once you have the tranny off, the hard part is putting it back on.

 

Hell to the NO!!

 

i didnt have a tranny jack. myself and my boss wrestled for 3 hours to try and get that fucking transmission and xfer case combo up into place while lying on our backs. shit sucked a barrel of bat dicks. never again. get the tranny jack if you value your sanity. this was on my 96 2.7 4wd manual. i wanna throw something just remembering how bad that sucked.

 

I had a transmission jack fully adjustable and it took me at least two to three hours to get it to line up with the dowel pins properly. It sucks.

 

Good to hear. Then I'll probably throw some degreaser on it then take it to a car wash and get everything off, then watch it for a day or so and make sure it's really the rear main. Then if it is I'll just go ahead and fork over the money just to have the piece of mind. It'll just suck if I replace it then it starts leaking again a few days later...

 

It shouldnt leak again if done by a professional. Its probably the cam plugs leaking off the backside of one of the heads atleast. Good luck new member!