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3rz rear main seal

23K views 36 replies 13 participants last post by  ShowStop 
#1 ·
Well guys,

I discovered today that I have a leaking rear main seal on my '97 3rz 4runner. Has any one attempted this fix on their 3rz or can point me in the way of a thread on how to change it? I'm a fairly competent weekend mechanic but this is project that will require me to drop the tranny to fix which I'm a bit nervous about.

The rig is 4wd and has 150k miles on it. If I have to take it somewhere to fix, I'm guessing its not going to be cheap thus I'm kicking around the idea of selling it for a newer, lower mileage 3rd gen.

Any thoughts are welcome. Thanks!!!
 
#3 ·
Well if you aren't confident I wouldn't recommend it. Its basically dropping the transmission, unbolting the flywheel - change seal - then reassemble. It should take a shop maybe 2 hours at the most so that's like $220 + the seal which should be like $20-$25 or close to that. I'm not sure what your exhuast system looks like cause that could slow things down... mine was a single exhuast off to one side so it wasn't an issue.

I wouldn't pay a shop more than $300 to do the work. Shops usually tell people $600-$700 for a new clutch replacement. So with the clutch and flywheel being about $300 and a couple hours work that's where that price comes from. I could do it in under an hour no problem if I used a lift. While it's off I would recommend a new clutch kit if you haven't dont that before. If a new clutch is put in make sure the mechanic replaces the pilot bearing which comes with the kit - and shows you the old one so you can see it. It's too easy to just say that they did it. If they have the right tool it's super easy but most of them don't have a proper bearing puller that isn't broken. I've dropped my trans out a few times so I know exactly what it takes. :D
 
#4 ·
Well it's an automatic tranny...so I'm guessing that makes it a bit more complicated. Sorry I forgot to mention hat important part before.
 
#5 ·
no more complicated at all. you still have to drop the tranny and pull the flywheel to get to the RMS. go to the FSM for all the details...faq/tech section. the procedure is not hard at all as long as you have the skills and a tranny jack.
 
#6 ·
Hey it's just easier to align the tranny when you put it back together. Go for it when you have an afternoon to wrench on it. : ) Just look around in the tech section and borrow a tranny jack when you're ready. Get a friend to help just in case you need some help aligning the driveshafts or moving the transmission up and down.
 
#7 ·
So after removal of the driveshafts...and all the mounting hardware...the transmission should lower right out...in theory. I assume the transfer case will come out too then?

Is the tranny a completed sealed, self contained unit or should I drain the fluid out of the pan and such?
 
#9 ·
Fairly easy even for a novice mechanic, auto trans is actually easier, with a standard trans you have to be careful not to bend the pressure plate when re-installing the trans plus the splines usually have to mesh together. With an auto you just slide the torque converter back in the trans, bolt the trans back up, rotate the moter to line up the torque converter bolts and bolt them back up. A transmission jack is not necessary if you have a buddy help you out. you can use a regular floor jack if you have to just be somewhat careful. I think that seal is a "wet" seal. Which means you will need to coat the inner lip with some grease before reassembly
 
#10 ·
Thanks Knuckle,

Thats the info I was looking for...! I read through the FSM and it doesn't look too bad.

So the torque converter needs to be slide off back into the bell housing? Does anyone have just a pic of the back of the engine with the trans off? That would be helpful.

Keep the thoughts coming!
 
#12 ·
Start by draining about 2 qts of oil from the engine.

The rear main seal is pressed into a rear cover. There are about 8 bolts holding that cover onto the engine block. Once the flywheel or flex plate is removed along with the heat shield, then you can unbolt and remove (pry off) that cover. Tap the seal out and replace. Also scrape off all RTV from both mating surfaces and the oil pan lip. Do not let any pieces of the RTV fall into the oil pan. If you do, drain the remaining oil.

Once the surfaces are clean, use Ultra Gray or Black RTV and apply a medium bead in the channel on the mating surfaces of the cover. Be sure to go around all bolt and alignment pin holes. Do the same to the lip of the oil pan and spread it around in the corners a bit. Just before installing the cover, apply GP grease to the edge of the seal and the outside of the crank. This will keep the seal from burning when you first start the engine. Do not get any grease on the RTV surfaces. Reinstall the cover and torque to spec.
 
#13 ·
Unbolt driveshafts, skidplates, take apart necessary shifter pieces inside truck and then the crossmember. support the trans with a jack, unbolt torque converter to flywheel bolts through acess shield (youll have to rotate the motor to get to each one so remove neg battery terminal to avoid any mishaps) remove starter and bellhousing bolts, unbolt trans fill tube from block, cooler lines from radiator,any electrical harnesses, seperate trans from motor (should come apart fairly easy but I have seen them stick together pretty good) If its stuck chances are you missed a bolt somewhere. Once seperated slowly lower the trans to the floor, remove flywheel, drain the oil,remove the seal housing (I always put a small amount of blue liquid locktite around the outer portion of the new seal, some grease on the inner lip and use a socket the same diameter as the seal to drive it in (slow circular taps to seat it evenly) Install is reverse of removal. Should be abled to do it in 4-5 hours with basic hand tools and a buddy in your driveway. If you have air tools and a general idea of how to remove a transmission 2-3 hours in your driveway. Good luck, it sounds worse than it is
 
#14 ·
I'm still debating on tackling this job myself, and I feel pretty confident that I can complete it myself.

I'm still a bit confused as to what the process is once I literally unbolt the tranny. Since I have an auto, what will I see once I remove it?

What other seals, parts should I order to complete the task? With this apart, would this be a good time to replace anything else? Any other tips and advice?

Thanks guys.
 
#16 ·
tranny jack is damn near a must with this job unless you bench press 300# on a regular basis ;)
a 3' (yes, that's foot) long extension to get to the top two bell-housing bolts...even then they are a pain.

pick up a Haynes manual or download/print out the FSM pgs that correspond to the job. (faq/tech section).
you will need a torque wrench.
 
#22 ·
Here are a few pics for ya. I know yours is auto and T4R. My kids rear main started to leak for no good reason that I could tell. Y2K Taco... but it'll give you an idea.

Based on your questions and experience, I would recommend AT LEAST having someone help you out that has had experience with such a project. It could go easy and straight forward or go to poop in a hurry making you wish you'd never got into it. Just my :2cents: Good luck with it!!

Me on the other hand, have been training my young... :p






 
#23 ·
Those pictures are really helpful. You look like a professional...and I'm debating now on hiring someone! Haha...any more pictures???
 
#25 ·
No where close to a pro, shade tree all the way ;)
That's all the pics we had.... sorry.

Don't get me wrong, I'm not trying to discourage you from doing it. Many good reasons to DIY like knowing your rig better, learning the process... shoot, add it to your resume'.

Keep reading, researching and weighing the costs in $$, time, effort, tooling, vehicle down time, mechanical ability and so on....(obviously your doing this else you wouldn't be askin' :)) ....anyway.... carry on.
 
#26 ·
Well I muse say, Im in the middle of my clutch job and its not THAT hard. It can be overwhelming and scary yes, but keep a kool head and stay confident and youll be fine.

It took me 6 hours (from the time I got on the ground to turn the first bolt till the time I got up and washed my hands) just to get the TRANS DOWN. Record time, Not nearly. But for a kid doing something this big by myself I'd say that's not bad. I have another truck to drive while mine is down so I can take however long as I want.

If you know how to turn a wrench I believe you will be fine. Just have a buddy you can call incase you get in a bind or have a question (thanks again Tyler :) )

FWIW, My past wrenching experience is : Starter, alternater, headers, and Lockright lcoker ( that I had help for) but the rest of everything I just dug in. :)
 
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#35 ·
Not to beat a dead horse, but you're gonna need a tranny jack. While technically the tranny can be dropped and reinstalled w/o a tranny jack, it makes it very difficult and dangerous w/o the jack. Also it's a little tougher to work on the ground; the shop has an advantage b/c they have a lift and they don't have to work on their back, LOL.

You should also consider servicing your tranny while you have it out and easily assessable. Inspect all the seals on the tranny & converter, too.

IMO, this is a weekend project for a novice wrench (that's me) if you should decide to tackle it.
 
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