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Replacing Rear Main Seal


pathybuilder
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I'm kind of stuck at a crossroads. After a full summer of house renos, I'm finally starting to work on my truck again. It sitting at a place right now where the torsion bars and transfercase / driveshafts are already out.

 

My 5 speed transmission was re-built less than 10,000km ago, flywheel resurfaced, and clutch replaced.

 

I'm debating whether to pull the transmission again to replace the rear main seal. I'm going into just about everything else on the truck and I would hate to have it start leaking in the next 10,000 - 20,000km. Removing the tranny would be easy enough at this point, but I would have to cut my y-pipe out as it's welded in place.

 

Has anybody had issues with this seal leaking, and how many miles/time were on your pathfinder before issues showed up.

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I haven't had to deal with a situation like your but, I'd do it if you are already that far into the project. I just went into my wife's Prelude for the third time this afternoon to replace a head bolt that was (hopefully) causing a minor oil leak. I kept thinking to my self how a job that originally cost me several months took just two hours!

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I always try to replace the rear main seal when I'm in there. Once they are replaced, usually it's no longer a problem(save for if you should happen to damage the seal during installation). I usually run a bead of silicone along the oil pan gasket while I'm there also.

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I have only done one once on an automatic transmission 4WD 1995 Pathfinder. I was 14 years old at that point and had a little over 200,000 miles when I did it.

It was not 'fun' spending all that time to replace one small $30 seal but it was leaking everwhere and loosing half a quart of oil a week, so I had no choice.

All the suspension and drivetrain stuff that has to be removed is intimitading to think about. Being 4WD doubles the amount of time to do the job, even with a lift.

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How many km's are on your engine now? My old 95 had over 400k on it and it never leaked. The new to me 94 I just bought, the PO had changed it when he replaced the transmission, though the seal was not leaking at the time. 30k later and it started to leak (it was an aftermarket seal, but I think it was installation error). I just had it replaced by a friend of a member here, we didn't have to fully remove the tranny, they just pulled it back enough to get the flywheel off.

 

Personally I say if its not leaking leave it. But if you do decide to change it, I would use a nissan part and follow the instructions in the FSM to the letter.

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I have only done one once on an automatic transmission 4WD 1995 Pathfinder. I was 14 years old at that point and had a little over 200,000 miles when I did it.

It was not 'fun' spending all that time to replace one small $30 seal but it was leaking everwhere and loosing half a quart of oil a week, so I had no choice.

All the suspension and drivetrain stuff that has to be removed is intimitading to think about. Being 4WD doubles the amount of time to do the job, even with a lift.

How many km's are on your engine now? My old 95 had over 400k on it and it never leaked. The new to me 94 I just bought, the PO had changed it when he replaced the transmission, though the seal was not leaking at the time. 30k later and it started to leak (it was an aftermarket seal, but I think it was installation error). I just had it replaced by a friend of a member here, we didn't have to fully remove the tranny, they just pulled it back enough to get the flywheel off.

 

Personally I say if its not leaking leave it. But if you do decide to change it, I would use a nissan part and follow the instructions in the FSM to the letter.

 

Yeah,

 

I like Adamzan's answer as I really didn't want to pull the transmission, but with all the suspension out now I think I might do it anyway. The truck does only have 225000 Km, so not nearly the 400 posted above. If I put everything back together and it starts leaking, It'll take me 4 times longer than if I just did it in the first place. Exhaust can always be welded again. I'll make sure to purchase a quality seal.

 

I don't suppose there is anyway to change this seal from the inside? I'm going to do the oil pan gasket as well because It's leaking a little, and the front diff is already out. I imagine once I drop the pan, I'll be able to see the crank shaft, but there will be no way to change the RMS as it's one piece and has to come out towards the tranny?

 

Thanks a ton for the suggestions guys.

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I used my floor jack, a slab of wood for support and a strap to hold it all together. Not too bad if you remove the T-bars and one crossmember. Personally, I just park in the street and let it drip from time to time.

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Yes, I rented a tranny jack (swore I'd buy one next time I do it and recommend the same). It was large and heavy, but I was by myself. The height I had to jack the truck to to get it to clear was a little alarming though (no lift). I was just wondering how Tungsten dealt with his tranny removal that 'it's really not that bad' for him. :shrug:

 

B

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  • 5 weeks later...

Well, I'm glad I pulled my headers off and tranny out. Having issues with photobucket right now uploading pics. The RMS was starting to seep, If I hadn't got to it I'm sure that within 20000km, I would've started to see oil on the ground. I wrapped a ratchet strap through the shifter hole then ran it into the cab where my fiance could slowly lower the tranny to the ground while I steadied and lowered it on a floor jack. It went much better than the last time I had it out, with two guys under the truck trying to balance it while lowering and moving it back. Anyhow, now I just have to get it back in.

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  • 1 month later...

With a MT a jack or 2 and or a cherry picker will do it...the at was much heavier so i bought a jack at hF for $200 and was well worth it

 

2012-12-27_18-34-07_347.jpg

 

Ive done the same with helping a guy in a parking lot in college with a strap thru the floor and a guy on each side pulling...it was interesting

 

But this is by far the way to go...wish i woulda spent this $ years ago

 

2012-12-28_23-05-48_327.jpg

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Where are those pics? I need to replace my RMS and would like to see what I have to deal with and how to do it on these engines. Thank you.

 

Once you get the tranny out as unccpathfinder showed above, remove the clutch and the flywheel. The pressure plate of the clutch has a loosening/tightening sequence to keep from distorting it. Mark the flywheel to crankshaft before you remove it.

 

 

IMGP0010-1.jpg

 

Mine wasn't leaving a big mess on the ground yet, but you can see from the seepage that it needed to be replaced.

 

IMGP0020-2.jpg

 

You can use a screwdriver to pry the seal out, just be very careful not to scratch the sealing surface of the crank shaft. Once I got mine started with the screwdriver, it pulled out very easily with a set of needle nose pliers.

 

IMGP0022-2.jpg

 

Use some Moly Grease to lube up the new seal. Set it in place and tap around the outside edges with a brass punch to push it into place.

 

Bolt the flywheel back up, torque to the specs in the FSM, Mount the clutch. An alignment tool would be handy. I found an 11mm 1/4" drive socket fits perfectly into the pilot bushing, used a 1/4" extension with a 5/8" 1/2" drive socket over top to centre the hub of the friction plate. This seemed to centre everything fine, but an alignment tool is likely the better way.

 

IMGP0015-2.jpg

 

IMGP0016-2.jpg

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