Read End Pinion Seal

[kool-aide]

I have a 99 z28 and I have had it for right about 2.5 years w/ 110k on the odometer.

Ever since I can remember I have noticed oil goo slung all over the underside of the car around the third member area.

I do not have drip leaks that are hitting the ground, never have. The only rear end leak I have had is a bad rear diff gasket, and bad install, :).

I was reading some of the sticky and it mentions to not change the rear pinion if you have seepage. I'm not sure what we consider seepage.

I'd like a few opinions on what every one things is a normal waste of rear oil vs. a real problem. The sticky also said don't change the pinion seal unless you know what you are doing. Well I have messed up a lot of things, so that puts me in the don't do it category.

My local estimate is 90 bucks for the diff service and 135 bucks for the pinion. Of course i was informed if the bearing is bad take that number and x4, ouch.

I would say I changed my rear diff fluid maybe like 6 months ago. in the 2.5 years i have had a 3 changes and 2 where like 1 week apart, the last one. Bad gasket install, oops.

So...

How do you know if I should change the pinion seal?
How would I know the bearing is bad? Is it all visual, or are there noises?
Since there is an additive to fluid ratio. If you have normal seepage, then how much fluid to additive to you add for small level fills? Or do you just do routine rear diff fluid changes to keep a good level and ratio? If i add a little rear diff fluid to keep up with seepage. Over time i will dilute the additive, so....seems like routine changes are something you should do more often.

thanks

kool-aide

[Firebirdjones]

Alot of questions in there but the one sentence that jumped out at me is someone telling you a pinion seal seeping is normal. :thinkin:

That's the craziest thing I've heard in a while. It shouldn't be leaking anything at all,,,,period!!!

If it is leaking there could be a number of things going on. First you need to look closely to see where it's coming from. If it's sneaking out behind the dust cover,,,,then it's the seal leaking. But,,,if it's coming out through the nut/pinion threads just behind the washer,,,then someone didn't apply sealant on the pinion splines when the yoke was installed.

It's the same procedure to fix either leak. Before I loosened anything, I would grab the yoke by hand and try your best to move it up and down, side to side, in and out. That will give you an idea if the nut is loose, backed off, or the pinion bearing is simply worn .
Best to hope it's tight, because the repairs get more involved.

For a simple seal change, scribe the nut and yoke for later, then remove. May need to tap pinion to slide it off. Remove and replace seal. Clean splines and apply a good sealant before sliding yoke back on. Check yoke seal surface for grooves, anything excessive may need replaced.
Install washer and nut,,,slowly tighten while at the same time feeling for play,,,once all play is removed you should be close to your scribe mark of the original position of the nut.
Once that is reached go past the scribe another 1/8 inch or so to keep preload on the pinion bearings.
Pinion nuts are pinched locking nuts,,,and once removed they usually don't hold as well the second time,,,,usually a new nut is the fix,,,but you can get away with reusing you original in this manner.
After finished tightening take a punch and hammer and peen the nut to the pinion in a couple places to keep it from loosening back up....just a precautionary measure I like to take with a used nut.

[kool-aide]

1st couple of sentences in this sticky

http://www.ls1.com/forums/showthread.php?t=7748

#2 item in second bold section

http://www.ls1.com/forums/showthread.php?t=17424


I myself would agree. Nothing should leak, not a faucet, radiator, or rear end mine or the car, :).

But if someone is going to tell me the pinion flings a little oil around is normal and can occur even after a fresh repair. Then I don't feel like throwing a couple of hundred bucks at something that may still fling oil.

I know people say they are poor all the time, well taking a 20% kick to the paycheck nuts can make a man poor. I am willing to fix my car, but i don't have free cash just because some guy at a local service shop said its broke. I take their advice and then evaluate the risk. Now if Obama has a stimulus package for FBodies, then I spend his money all day long, :).

I don't hear any noises other than what I have been used to for 2.4 years. AS a matter of fact there is a low odd groaning noise that has gone away. It was low speeds like in and out of drive way or pulling away from a stop sign. I have not noticed it at all. Maybe it was low rear fluid, who knows.

Like I said, I don't have a single drip drop of fluid on the ground. My drive way is absolutely clean. My car spends 3 days out of the week sitting perfect still in the drive way. For you math folks out there 20% = 4 day work week, yes, I'm still angry corporate greed thinks its OK to shaft the lil guy.

I would classify the rear end as leak free. But obviously a lil oil and goo is coming from some where, and back there it should be the rear end.

[Firebirdjones]

I read your link,,,I don't know who Keliente is,,,,and I do like this website, it has alot of good information with good people that mean well,,,but I have to say that is the worst advice I have ever read. It will not leak again after a fresh repair unless the repair was done poorly. PERIOD!!!

If your seal is seeping,,,just fix it as I described. The seal will only cost $3-$4.00,,,,it's not a bank breaker. And it's only 30 minutes of your time.

Now you can listen to the people that tell you it's still going to leak,,,or you can listen to yourself deep down knowing it's not supposed to leak and just fix it properly and enjoy a nice leak free dry car underneath. It's your car, up to you. I'm not the type of person to steer you wrong, I can't make a living at this stuff sending cars outta here with leaks,,,Know what I mean ;)

[cammed goat]

I bought my car with a leaky pinion seal. Didn't leak that much in the past 1-1/2 years I owned the car, but I got tired of my car smelling like it had a skunk living underneath it(exhaust runs under rear diff). Took it in for a warranty repair and all is good. No more leak.

[Cutlass]

....For a simple seal change, scribe the nut and yoke for later, then remove. May need to tap pinion to slide it off....

Just wanted to add, scribe the pinion also. That way when your done, all three lines should line up.

Also agree the rear should leak a drop of oil...but seepage seems to be the norm on our diffs. I classify seepage as a small leak that doesn't form a drip and/or doesn't drip on the road. Sounds like you have seepage.
I tried fixing mine with a GM seal and it started leaking a week later. And the pinion yoke looked good. If you're gonna fix it, I would recommend a new yoke and seal to hopefully get it fixed the first time (unlike me :( )

[kool-aide]

Firebirdjones, I'm not sure I follow the last thing you mentioned about punch, hammer, and nut?

you said, After finished tightening take a punch and hammer and peen the nut to the pinion in a couple places to keep it from loosening back up....just a precautionary measure I like to take with a used nut.

I haven't sat under the car staring at it, so i really have no visual to your statement.

It also seems your idea of a repair is way to easy to believe, :). I have found all my repairs to be a PITA.

Let's assume the only thing i will replace is the pinion seal. What parts should i replace? You mentioned nuts, the seal, etc.? Are these parts I should be able to find at like a Napa or Auto Zone? I don't have O' Reillies or any of the others. I would say Napa is like the best in my neighborhood.


Cutlass, how much would the Avg yoke cost? That sounds exp to me.

I'm not trying to be cheap. I'm trying to figure out what I can do without rendering my car dead and what I should have a shop do. To give you an idea I can change brakes, rotors, trans mount, plugs & wires, shocks, upper lower control arms, water pump, alternator, A/C line, etc. I even changed one motor mount before declaring defeat and taking it to a shop, :). I could have done both but I threw in the towel out of aggravation.

So, I'm not a compete noob on car repairs, but I certainly have my share of screw ups that cost more than they should.

Shouldn't you use a torque wrench instead of scribe and 1/8 turns? I like torque specs because i end up breaking things other wise. I would rather spend a 100 bucks to get a torque wrench than 100+ bucks cuz i busted a bolt or something.

I do agree the car should never leak. But i don't want to start a fix and end up with a leak.

[kool-aide]

I bought my car with a leaky pinion seal. Didn't leak that much in the past 1-1/2 years I owned the car, but I got tired of my car smelling like it had a skunk living underneath it(exhaust runs under rear diff). Took it in for a warranty repair and all is good. No more leak.

lucky you. A 99 w/ 110k is not exactly under warranty, :(.

[kool-aide]

here is what the good ole Haynes says. Sorry, but i seem to always quote the book even though i don't always agree, lol.... But i must say it does help me, sometimes.

1 Disconnect drive shaft
2 use inch lbs torque wrench to find the torque it takes to rotate the pinion
3 scribe marks on the pinion shaft, nut and flange
4 count the visible threads on the end of the nut and pinion shaft?
5 How do you keep the companion flange from moving? book says special tool or pliers, shrugs?
6 remove pinion nut, oh boy now we're talking
7 pull off companion flange, may need 2 or 3 jaw puller, ain't got that, but never pry behind the flange or hammer the end of the end of the pinion shaft.
8 pry out old seal
9 lube new seal with all purpose grease, tap in evenly w/ install tool or large socket, i got lots of big sockets, make sure it goes in square and full depth
10 align mating marks and put the flange back in. don't hammer flange in, if needed use pinion nut to draw into place
11 apply non-hardening sealant, uh oh whats this? to the visible spline ends in the center of the flange so oil will be sealed in. OK this part seems really important to a good seal.
12 install washer and pinion nut. tighten carefully until original threads are exposed, from step 4.
13 OK this says record torque to rotate pinion. then apply small increments til you hit the original number. then go an additional 10-15 inch lbs past the orig number. this must be your 1/8 past orig comment. don't over tighten and don't back off the nut after it has been tightened.
14 connect drive shaft, :).

I am paraphrasing of course and no pictures, lol... So your install help sounds exactly like Haynes, only fewer words, :).

[kool-aide]

I have a really dumb question. It doesn't sound like any oil will leak out during this. So I am guessing I shouldn't rush out and buy oil and additive for this change. After I am done I will check the level by opening the fill hole and sticking my finger in it.

[Firebirdjones]

I'll try to cover this.

As far as peening the nut,,,the very outside end of the nut needs to be smashed against the threads of the pinion, in order to keep the pinion nut from backing off later down the road. I use a punch and hammer, a small chisel will work too.

As far as leaking oil during the change,,,yes some oil will run out when you remove the old seal. You may need to add a small amount, but not much. Depends on how fast you are at installing the new seal :D

As far as pinion nut torque,,,,there isn't one,,,but I need to explain. When setting up the rearend initially,,,you tighten the pinion nut to crush the pinion sleeve against the pinion bearings,,for preload on the bearings. There is no set torque rating for the nut itself,,,,you simply use an inch pound wrench to rotate the pinion and check the drag on the bearings. New bearings require about 30 inch lbs. of drag while rotating.
Now the catch is you have to check this inch pound rating while the PINION ALONE is in the housing,,,no axles,,,no ring gear,,,no carrier etc....
So the book you are reading for a pinion seal change means well,,,but it's assentially wrong. There is no way you can check for proper inch pound rotational drag on the pinion with the rearend assembled,,,you will be turning the carrier and it's bearings, as well as axles and their bearings,,,along with rear brakes dragging etc.....Don't do it that way,,,it's just not accurate.

Simply mark the nut as described and return to that position,,,then simply go another 1/8 inch past for a small amount of preload,,,that's it.

As far as new parts,,,,I'll touch on the seals that cutlass mentioned. I have had bad luck with pinion seals from GM,,,,don't ask me why,,,I have no idea,,,so I use a good seal from any parts supplier,,,I prefer National,,,and never had a problem.

The yoke?? It really depends on how worn it is. If it's not bad the surface can be cleaned up with a mild emery cloth. I also like to apply grease to the seal surface to give the seal a fighting chance.

The nut??? Just depends on what you want. They can be had most anywhere. Anytime you setup a ring and pinion and by an install kit with shims,,,they come with a new nut. For a simple pinion seal change I usually don't bother with a new nut,,,and just peen it as I mentioned. These are smash lock nuts,,,meaning they aren't perfectly round, more egg shaped,,,that's how they hold their position. After being installed and removed again, they tend to not hold as well,,so I peen them.
Anything else just ask, we can get it straightened out no problem.

[Cutlass]

5 How do you keep the companion flange from moving? book says special tool or pliers, shrugs?


If you have a 1/2" drive impact wrench, you can hold with your hand the flange while loosening and tightening the nut. I usually wear a mechanics glove or hold a shop rag to protect/cushion my hand from the flange rattling against it.

Don't worry about additive, a small top off of gear lube will finish the job off just fine.

[kool-aide]

oh sure Cutlass if i only had an impact wrench. Nope, haven't bought the good tools yet. tx, one day i will have an air compressor and air tools, one day....


Tx for all your help Firebirdjones,
peen, lol...i guess the first time i get under there and take it apart it may start to make sense. sitting at my desk with no visual clues at all just sounds Greek to me, :). It does sound easy, until the peen, hah. If you see a blue z28 off the side of the road that would be me and my bad peen, lol...

[Cutlass]

I do then all day, every day without peening so have no fear. Peening is a good idea though.
Doing it without a 1/2" impact though would be a pain. I've never done it anyother way, and not sure I would try it.

[Firebirdjones]

I do then all day, every day without peening so have no fear. Peening is a good idea though.
Doing it without a 1/2" impact though would be a pain. I've never done it anyother way, and not sure I would try it.

I agree I prefer the impact method. Although I did make a tool that bolts to the yoke, with a hole drilled in the middle for the socket to fit through,,so I can hold that yoke still while turning that nut. It's rather tough to do though without the impact.

[kool-aide]

maybe i will get lucky and find a tool at the parts store?

[chuckunit69]

I agree I prefer the impact method. Although I did make a tool that bolts to the yoke, with a hole drilled in the middle for the socket to fit through,,so I can hold that yoke still while turning that nut. It's rather tough to do though without the impact. easiest way without an impact is an extreemly large pair of channel locks to hold the yolk. its not pretty but it works

[kool-aide]

that i have, tx

[98Hardtop]

I did mine today at my work being I was off. Having all the impact tools made it much easier.

[chuckunit69]

oh i agree impacts make everything easier i try not to live without em lol

[98Hardtop]

I also had 2 GM techs making sure I did everything ok. Granted the method was different than above, but these guys have been doing it that way for years.

[kool-aide]

yes, i have spent many hours swearing i would run out to buy air tools only to suffer without them time and time again. I don't have air tools, but i am convinced they make every thing easier. One day, one day I will have the money. I have the spot in my garage reserved and ready. I even put in a new 20 amp breaker, just waiting patiently.

i still haven't changed it yet. We tackle our project list one pay check at a time, to make sure we don't spend out of control. This weekend is new radiator hose clamps for the Sebring. I may pick this weekend to try the pinion seal. I am so afraid I will get have way through it and get stuck. Or worse do the whole job and have a drip leak because i crushed something.

[Cutlass]

I would say it'll be very difficult to retighten the pinion nut without an 1/2" impact. You need to be able to bolt something to the pinion flange that you can wedge against the body or the ground while you use a 24" breaker bar to tighten the pinion nut.

[chuckunit69]

I would say it'll be very difficult to retighten the pinion nut without an 1/2" impact. You need to be able to bolt something to the pinion flange that you can wedge against the body or the ground while you use a 24" breaker bar to tighten the pinion nut. its not easy and normaly requires a good non homofobic freind to be stuck under the car with you:beer: will need to be provided

[98Hardtop]

I took the liberty to make a How To. This is how we did it.

*Disclaimer. I am not an expert and this was my first time attempting this. I am sure there are easier and better ways to do this, but this method worked for me. Sorry I did not get any pictures. Of course I work with 2 former Gm technicians and they helped me through this to make sure I didn't screw it up

Tools needed:
11mm wrench
34mm socket
Hammer
Chisel/punch
Flat head screw driver
Jack stands and a jack

* It is highly recommended to use an impact gun during this repair. Otherwise it can make tightening the pinion nut pretty difficult.


First thing you have to do is raise the vehicle up into the air. I used a lift at my work so that made the job that much easier. It can be done with jack stands but will make it more time consuming.

Once supported, take your 11mm wrench and undo the 4 bolts that hold the driveshaft to the yoke. Remove the driveshaft to allow room for the impact gun.

What you need to do now is scribe into the nut, yoke and gear all in the same place to mark as a reference. I used a punch and hammer. I also counted the amount of threads the nut was on. You need to do this so when you put it back together it is at the same spot for torque reference.

Remove the nut with an impact gun using the 34mm socket. You may get some gear fluid onto you, so be prepared. You may have to tap on the backside of the yoke to get it to come out.

Once the yoke is out you will need a flathead screwdriver and either pry or chisel out the old pinion seal. Once the old one is out you can place the new one in. I used a hammer and hammered it in evenly on all sides on the outside edges of the seal. This process requires using the right amount of force. You don’t want to hammer to hard or too light.

Now you reverse your steps to reassemble everything.

Notes- I also took some emery cloth and cleaned up the inside of the yoke to make sure any burrs were removed.
Also when tightening the nut, if you go past your marks DO NOT BACK IT OUT! leave it where it is.

If I am missing anything on this, please feel free to post up.

[Cutlass]

Sounds about dead on to me! Good write up!

[Firebirdjones]

Don't forget to apply sealant on the splines,,,,or you'll have a leak all over again,,,coming out through the nut/washer.

[Firebirdjones]

I would say it'll be very difficult to retighten the pinion nut without an 1/2" impact. You need to be able to bolt something to the pinion flange that you can wedge against the body or the ground while you use a 24" breaker bar to tighten the pinion nut.

Exactly, I mentioned earlier in here somewhere that I made a tool to bolt to the yoke out of 4 inch flat stock, with a hole drilled in the middle.
Also perfect for checking preload on posi unit clutch packs.

[98Hardtop]

Sounds about dead on to me! Good write up!

Thanks. I replaced a trans mount yesterday and no leaks.

[kool-aide]

thanks to everyone

[98Hardtop]

I take it went ok?

[kool-aide]

funny, we sold the car for the Silver 02, my avatar.

I'm have resurrected the thread to ask a follow up question.

Would you have oil goo in the tunnel above the yoke if the pinion seal was leaky?

I noticed on the 02 the carrier is dirty gooey filthy. There is oil stained gunk around the edge of the cover and on the fill side it is nasty and gooey.

the tunnel area looks clean though. my 99 had under body coating and always made it hard to spot stuff. this 02 does not, so i can clearly see silver paint above the yoke area.

the passenger side of the carrier is the nastiest. the drivers side for some reason looks clean-ish. of course the torque arm is on the drivers side, lol...

i also noticed the passenger side of the axle shaft is yucky and the driver side is just rusty.

it seems about half of the goo under there looks old and dry. The rest seems newer and you can easily finger wipe it off. Kind of like nice oil road grim goo and dirt.


when i was first under their i wrote it off as someone made a huge mess since it seemed to only be around the fill plug. Maybe it is maybe not. I know I always wipe down my mess so not sure.

now i wish i had taken pics of my old 99 or had it in the drive way. I can't remember all of it, damn old age, lol...