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Thread: Rear differential leak and pinion seal replacement

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    Van Fan YOTAMOG's Avatar
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    Rear differential leak and pinion seal replacement

    Any tricks/tips on replacing the pinion seal?

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    Administrator timsrv's Avatar
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    Re: Rear differential leak and pinion seal replacement

    The big thing here is putting the nut back on to the exact position. The pinion nut is what determines the pre-load on the differential so marking & re-positioning to the same spot is critical. There are several videos on youtube to help prepare you for the job. There's a few specific to Toyota I would watch simply to familiarize yourself with the components. I would not however put a lot of faith in the techniques used by the "mechanics" (at least not some of the ones I watched). I liked one video of a guy doing the job on a GMC........particularly the way he marked & re-positioned things. I would recommend using his technique to re-align & tighten the nut after replacing the seal.

    http://www.youtube.com/watch?v=15zHpz6Zx8c

    In the factory service manual starting on page RA-8 is the Toyota procedure. I would recommend checking that out too. But the problem with the manual is reliance on special Toyota tools. I like checking out the youtube videos as they show other ways to get the job done. I would recommend watching several but don't put too much faith in some of the wannabe mechanics there . The bad ones are usually pretty easy to spot. Tim

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    Re: Rear differential leak and pinion seal replacement

    Hey thanks Tim. Worked on it at the lake before the wind came up and blew too much sand around. Didn't mark it all out like the guy in the video, hope I won't have any major issues later. Found the nut was just barely more than finger tight upon taking it apart and put it back together just barely tighter, assuming some wear in the 380K miles on it.

    I would recommend putting the rig up on jack stands instead of ramps so the pinion nut can be turned by the wheels to allow better access to the detent. The fuel tank is right next to the driveline there so it's kinda tight if the nut isn't lined up (like mine was). Probably remove the entire driveline too, instead of wiring it up and out of the way. Other than that a pretty simple task.

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    Re: Rear differential leak and pinion seal replacement

    I'm totally lost on this "simple task" Please help! I don't understand what I'm looking here, where is this supposed to separate from the differential? Is this part of the companion flange? How do I get it off? I read the manual after I started this job and now I can see this is way more complicated than I'd ever imagined. I don't even understand what I'm checking the torque against when I use this torque gauge that I don't even own. And can I change just the seal or do I have to change the bearing and spacer too in order for this leak to stop. I'm so frustrated right now. It looked so easy in this thread! http://www.toyotavantech.com/forum/e...Rear-diff-seal but now I see that that is for a Previa!


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    Red face Re: Rear differential leak and pinion seal replacement

    You got that far to expose the seal, the hard part is over! Get the old seal out with a seal puller tool -or- just use a big screwdriver and pry it out against the diff housing. Just be careful not to damage the surface the seal touches around the perimeter. You can totally ruin the old one, even punch the screwdriver into and through it and "fold" the seal to shorten the diameter using a hammer to beat on the screwdriver and it will come out. If you don't have a socket the same size as the seal I actually used a quart jar! I don't recommend that technique as the glass could shatter in your hand. Bad. It's all I had though and it worked to get the seal started. You can also try using a small hammer and tapping lightly around the seal a teeny bit at a time, working around and around until it seats flush in the diff. Lightly coat the rubber with oil (on shaft too). I didn't have a torque wrench either as I was on a road trip when mine started leaking. I gave mine about 1/8 of a turn past snug and it's still holding Then put 'er back together and top off with your favorite flavor of 80/90 gear oil.

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    Re: Rear differential leak and pinion seal replacement

    Ok Thanks! I wasn't sure how to proceed because I was not expecting to see a metal plate behind the flange. I took your advice and beat the crap out of it with a screw driver. The diff is all back together and not leaking anymore! I was worried about getting the retainer nut back it the same spot because when I removed it I didn't count the turns. I did this job with out jacking up the van though so I could be confident that nothing moved and it was obvious where the nut had been staked in so I can be sure it is back in the same spot. Thanks for the help!





    Last edited by saucymonkey; 09-20-2015 at 01:29 PM.

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    Re: Rear differential leak and pinion seal replacement

    Does the original seal have a metal outer part? The new seal you [Saucymonkey] put in doesn't look [metal] like the old one you destroyed with the screwdriver.

    At one point I was on the road and worried because my diff started leaking out the pinion seal. I took it to a dealer and paid way too much to have them replace the pinion seal. After they replaced the seal the leak was even worse than before. I took it back and asked them to retorque the nut. It still leaks. They told me that my shaft is probably worn where it meets the seal (i have 300K mi) and therefore the new seal did not fit snug around it. Can anybody tell me if this is a BS excuse, or if it is a plausible explanation for the continued leak?

    I'm beginning to think I should re-replace my seal by myself.

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    Re: Rear differential leak and pinion seal replacement

    In that video I posted, before the guy removes the drive shaft he grabs it and jerks it up/down, back and forth. He's doing this to check for play in the bearing/shaft of the differential. If there's play here the seal won't hold up (it's why you do it before taking the trouble to replace). If your mechanic knew what he was doing he would have done that (a good mechanic will always try to find a bigger problem before repairing a symptom). The other thing the video guy does (near the end) is put RTV on the outside periphery of the seal before putting it back. This helps the seal slip into place and also helps prevent oil from leaking between the seal and the housing. He also put RTV on the splines before putting the yolk back in. If they skipped either of those steps it could explain the leak. On ours, the drive line parts link up pretty tight, so even if they skipped sealing the splines, it probably wouldn't leak much. Of course there's also the chance he damaged the seal during installation.

    Different brand seals will be different. Even OEM Toyota may or may not have metal anymore. I would consider that a non-issue as this area is pretty well shielded from impacts. Tim

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    Re: Rear differential leak and pinion seal replacement

    Thanks, Tim! Probably a moot point by now, but I'll check for play. My persistent pinion seal leak has worried me and it sent me on a hunt for a new-used rear diff. Remarkably, I found one!! donated to me by, none other than, saucymonkey. Planing to swap out the third member sometime in the next 10K miles.

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    Re: Rear differential leak and pinion seal replacement

    Quote Originally Posted by fuquan View Post
    Thanks, Tim! Probably a moot point by now, but I'll check for play. My persistent pinion seal leak has worried me and it sent me on a hunt for a new-used rear diff. Remarkably, I found one!! donated to me by, none other than, saucymonkey. Planing to swap out the third member sometime in the next 10K miles.
    Hey Dan! I didn't realize that was you. I used a Car-Quest seal that was part #1177 and its probably made by National. It is metal but its completely rubber coated so it should have no problem sealing the outer surface.
    That piece definitely could get a groove worn in it to the point that it won't seal. Mine only has half the mileage of yours and I could feel a slight groove. It looks like new ones are available but I'd check the one I gave you first
    .
    http://www.toyotapartswebstore.com/a...01-651420.html

    Its possible they messed up something else though, I don't have much confidence in dealers. Now that I've done it once I wouldn't hesitate to do it again.

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    Re: Rear differential leak and pinion seal replacement

    So a "simple" job would you say? It seems overwhelming some jobs. But sometimes ya gotta dive in and likely learn a some things when you don't have the right tools or experience. But chock it up to another job well done if it isn't leaking. Experience comes from adversity. Not exactly excited about the queue at my house...

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    Re: Rear differential leak and pinion seal replacement

    Here's a question from a buddy of mine who did a rear end swap and and is now stuck-

    Finally found a used tranny from an 84 in the Spokane area! Just finishing the swap out and decided to replace the rear differential/pinion seal as it was starting to leak. The large pinion nut has to be removed and the small yoke that bolts to the rear u joint is pulled out of the seal to replace it. My question is, what is the proper torque setting for that pinion nut? I looked on the Toyota forum but couldn't find any info. The local Toyota dealer asked one of his techs and they couldn't pull it up on their computer! He mumbled something about a crush sleeve that you had to be careful about? This nut sets the tension on the gears/bearings inside the diff.


    Any help would be greatly appreciated.

    Thank you


    Thanks for your help JDM

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    Re: Rear differential leak and pinion seal replacement

    This site, although written for the 4x4 Toyota trucks, is still true for our vans. Hell, I even think the pinion seal is the same part number. The job is the same regardless. Anyways, per the site, what you're supposed to do is mark EVERYTHING with a sharpie and remove the staked nut. How to do that without messing up your pinion pre-load is to "count the number of turns needed to remove it and reinstall with the same number to retain the pinion bearing pre-load." By mark everything, I believe you're supposed to mark the nut, bolt, and flange and count rotations. I went a step further and marked the side of the socket as well because I obviously couldn't see the mark on the pinion nut with the socket on it.

    On the last page of the site he writes that factory torque settings are 54 ft. lbs, not sure how accurate that is. I did this job a couple of years ago just counting turns on the staked nut and it worked fine for me.

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    Re: Rear differential leak and pinion seal replacement

    Nice man thank you for your quick reply

    JDM

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    Re: Rear differential leak and pinion seal replacement

    Here's my buddy's reply and inquiry-

    Thank you for posting and thank you AD 2101 for a prompt reply! The process of restaking a new pinion nut seems a bit mysterious to me. How precise does this tension need to be? I journeyed over to my local Toyota mechanic and he grumbled a bit and finally pulled the 85 factory manual out of his closet. It turns out to be quite an elaborate procedure to reset that nut to a precise setting. The final tension on the internal gears should be 4 to 5 ft. lbs. as measured by a special factory torque wrench that measures the force needed to start the rotation of all the gears out to the ends of the axels. (I was looking over his shoulder, so this might not be totally accurate) When I unstaked my nut I could remove it with my fingers, so obviously it was too loose! There apparently needs to be a slight but precise preload on the internal gears. Gut feeling tells me to snug that nut finger tight and then give it a slight bump with the ratchet and call it good. ??

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    Re: Rear differential leak and pinion seal replacement

    did this today on my automatic 84LE, took pictures to document:

    first, watched youtube vids (recommended by Tim: https://www.youtube.com/watch?v=15zHpz6Zx8c) then read the manual. jacked it up and got it on jack stands, then checked for play in the Ujoints and the bearings, we were good.



    got the driveshaft off after marking the position with a paint pen. these bolts took a ton of torque to get off. 12mm bolts and nuts. after getting the bottom two loose, we put the van in neutral turned the tire until the top two bolts were on the bottom. put it back in park then loosen the last two.



    had a visit from a tarantula, this was after he crawled in my tool bag



    drained the oil. 24mm bolts, careful not to round the bolt off, using a 6 point ratchet.



    manual said to use a chisel to "loosen the staked part of the nut" we used a small flat head and a big ole galvanized nail. did the trick.



    first we marked the postion of the nut so we could get it back on the same as it was. then, as we didn't have SST 09330-00020 we drilled a couple holes in a spare piece of steel and bolted it onto the companion flange. then we pulled the pinion nut off using a 24mm socket and a breaker bar. it wasn't super tight.



    had this puller laying around and it was perfect to get the flange off.



    once the flange is off we can see the old seal (missing quite a bit of rubber). getting it out was hard without the right tools. managed to get it off (and mangle it) using a flathead and a hammer.



    the old seal is dead.



    here's a look inside at the oil spiller after pulling the old seal.



    put the new seal in, after putting a thin layer of silicon on the outside, by tapping it in slowly with a hammer around the outside of the new seal. also put silicon on the splines on the inside of the companion flange.



    here it is all back together. with the nut pretty dang close to where it was originally. used a hammer and blunt chisel to stake the pinion nut back down. after this, we reattached the 4 12mm driveshaft bolts (430 kg-cm (31ft-lb, 42 N-m)). then refilled the gear oil in the differential. 1.3qt 80W-90 is what we used. really helped to drop the spare tire to refill it. test drove it and so far no leaks.

    hope this helps someone in the future. total cost was about $40 for a new seal, new oil, and some silicon.

    cheers!
    Last edited by shindagger; 10-29-2018 at 03:44 PM.

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    Re: Rear differential leak and pinion seal replacement

    Awesome!!! Thanks for sharing

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    Re: Rear differential leak and pinion seal replacement

    I Have a soon to be running 87 manual 4x4 project and pulled the leaky pinion seal before reading this thread and learning about the required preload/marking the nut before removal. When draining the rear differential oil, noticed quite a bit of metal shavings on the plug and also seems to me a touch of play on the shaft. Recommendations on an appropriate next step? I've cosidered pulling the axle and having it rebuilt by a reputable guy. I've also read the 2wd 85-96 truck axels have same axle(7.5 gears)? Should I hunt one down and swap? (Am I missing something on that idea that needs to be considered? Any guidance greatly appreciated- thanks

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    Re: Rear differential leak and pinion seal replacement

    I just replaced my pinion seal after a leak developed after I had a shop rebuild the rear diff. I brought it back to them and they replaced the seal and said the shaft was badly scored but they couldn't find a repair sleeve for it... go figure since it's the same flange used on pretty much every Toyota truck/van made between 1986 and 2000. This only made the leak worse and my trailer and dirt bike got sprayed with gear oil (grrrr....) Anyway, I easily found the repair sleeve at local auto parts stores. The part needed for this repair is #99147 whether it's an SKF Speedi-Sleeve or the one made by National that I ended up with, for a 1.1496" shaft. It's easy to tap the sleeve onto the shaft with the included tool, providing a smooth surface for the seal to ride on. I then replaced the seal using RTV on the outer seal and splines. The shop had neglected to put sealant around outside of the seal, which was metal so the oil just leaked around it, hence the leak getting worse when they attempted to fix it.
    My manual says to refill with 1.53 quarts for 2wd and 1.96 quarts for 4wd, or just up to within 5 mm of the filler hole. I was only able to get about 1.5 quarts in my 4wd before it started pouring back out the filler hole.
    Last edited by Hammervan; 07-17-2020 at 11:22 AM.

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