Just wondering if I missed one on the front driveshaft.

I got the rear, but never checked the front.

Also, is there a fill plug on the rear diff?

There's a fill plug on the rear diff on the first gen, no greese fittings on the drive shaft though.

Yours might be different though, but I can basicly promise that you have the plug on the diff.

Look pasanger side about 1/2 way up, and about 1/2 way between the axle tubes and the front.
Mine takes a 1/2 drive rachet.

Awesome, will be replacing the fluid with synthetics soon.

The front diff was checked and the oil was relatively dirty for only having around 15,000miles on it.

Also, by the looks of it, I have a seal leak on the driveshaft seal of the rear diff.

Seems to be rather slow leak that never makes it to the ground.

I wonder if some leaked out whe they were replacing the transmission and had the driveshaft out.

Can diff fluid leak out when the driveshaft is out?

It shouldn't. The slip yoke is on the transmission (or I should really say T-case), so it shouldn't change a thing on the rear diff.

If you have a posi back there don't use synthetic, or it'll never lock both wheels up at once. It's just too slippery for the clutches to grab.

Hmmmmmmmmmmmm.......

I don't think I have a posi on a 1995.

I do on my 85, so you just never know until you look. It'll have some internal springs if it's posi. Otherwise no springs.

The factory u-joints don't have grease fittings. If they were replaced, they should have fittings unless they were replaced with the sealed "lubed for life" u-joints.

The rear diff does have a fill plug. It is located on the passenger side of the housing just little forward and below where the axle tube is. The plug has a square hole. You can usually remove it with a rachet by putting an extension directly in the hole. The corners on extensions are slightly rounded and don't fit perfectly so if you're not careful you can mess up the plug. I normally replace the factory fill plugs with one that has a standard bolt head.

A small leak at the front of the rear diff is pretty common. It is the front pinion seal. The yoke is mounted to the diff independantly of the drive shaft and the drive shaft connects to the yoke by the bolts on the u-joint straps, so removing the drive shaft won't effect the seal.

I'm currently running synthetic gear oil in my posi rear and haven't noticed any problems. Just make sure that it is GL-5 gear oil and intended for "complete fill" and not "top off only".

You can check the codes in your glove box to see if you have a posi rear. Look for G80.

Awesome, will be replacing the fluid with synthetics soon.

The front diff was checked and the oil was relatively dirty for only having around 15,000miles on it.

Also, by the looks of it, I have a seal leak on the driveshaft seal of the rear diff.

Seems to be rather slow leak that never makes it to the ground.

I wonder if some leaked out whe they were replacing the transmission and had the driveshaft out.

Can diff fluid leak out when the driveshaft is out?

Always check the axel vent valves and hoses if the seal is leaking and better yet check them before they start to leak or when you service it.
If they are stopped up pressure will build up in rear ends and blow out greese.
MT

I will look into that.

The leak seems to be only leaking on the underside of the front of the diff and being pulled by the wind back along the bottom.

Nothing ever hits the ground which is not really making me worried.

Sometimes the synthetic will replump up the seals and thus the leak will subside.

This is my hope.

I bit the bullet and purchased 3 liters of MotorMaster Synthetic 75w90 and redid the fluid in the front and rear diff.

Stuff is pretty thin compared to what was coming out. Though through driving I cannot find one single problem or noise.

Found a problem with Mr.Lube's though (Lube Shop chain in Canada). I paid to have the front and rear diff's changed two years ago. The rear diff had relatively new fluid though the front fluid looks to have never been changed.

Was really black and grey and also had some condensation in it. Looked nothing like the rear although they were "supposed" to be changed at the same time.

Oh, little tip, make sure you are not right under the rear diff with your body when you remove the fill plug. My body acted as a drain pan for about 1/2 liter of gear oil. That stuff stinks and tastes like p00p.

Used a hand pump to pump out all the fluid and luckily there was enough room to fill directly from the bottle.

Took all of 3 liters to do both of them. Thought I didn't buy enough until the last bit was put in and low and behold, it was at the perfect level.

Just to be sure, it is just to the bottom of the fill plugs for the fill level right?

That should be the perfect level.

Sorry I should have warned you that it stinks.

Sounds to me like it was overfilled, which might be why it was coming out the front seal.

Figures that they didn't change the front :mad:

I never thought of just pumping out the back, and always pull the cover off of Chevy's (wouldn't do that with a Ford 9")

That should be the perfect level.

Sorry I should have warned you that it stinks.

Sounds to me like it was overfilled, which might be why it was coming out the front seal.

Figures that they didn't change the front :mad:

I never thought of just pumping out the back, and always pull the cover off of Chevy's (wouldn't do that with a Ford 9")

Well, the rear was up on ramps when I removed the plug so I shoulda known better. Quite a bit did some out though, but it might have been from the angle.

I don't even know if they changed the rear plug. The amount of crud and rustproofing oil I had to remove had to have been more than two years worth.

Took a good bit of effort to clean out all the crap so I could remove the rear plug.

The pump did work rather well though, took a little elbow grease, but saved me from removing the cover and such and keeping things undisturbed.

The front diff fluid was quite thick as well, and really black. With the limited about of 4x4 use I do, it should have been practically new oil.

Does the front diff spin when driving in 2wd or is it disengaged?

There is some movement in the front diff whenever we drive, but I really don't know how much. It'll be less than the rear diff though.
I've never taken any apart, so I really don't know what they're like inside.

Oh, and while doing this, I found out that my front differential is leaking fluid like a mutha fudder out the rear driveshaft seal that goes to the transfer case.

So bad that it is leaking fluid onto the exhaust pipe when the air catches it and throws it on the pipe and causes a bad stink.

Seal is cheap and so is the labor so I will be getting it fixed tomorrow. It is leaking bad enough for me to no drive it and I don't have the tools to install it myself.

Figured the synthetic 75w90 cleaned something out that was plugging the seal OR the fluid is too thin. No noise from the diff so I think it was the cleaning of it.

I need to stop working on my truck, I make more work than I save......

I just took my truck in to have the pinion seal replaced today, is this what you are having replaced LT?

I need to stop working on my truck, I make more work than I save......

Your Blazer will last years longer now due to the work that you've done, and this might be a good thing depending upon how you look at it

I just took my truck in to have the pinion seal replaced today, is this what you are having replaced LT?

I have no idea what it is called.

It is leaking where the front driveshaft connects to the differential.

Flinging gear oil all over the place.

The only thing that stinks worse than gear oil is burning gear oil.

Haha, I personally like the smell of gear oil, maybe I am odd?

Haha, I personally like the smell of gear oil, maybe I am odd?

No your just :screwy:











































:evillol: Just kidding, we're all different that way

Seems to be a cheap job to get done.

About US$60 bucks to get it done.

Welp, you are going to laugh at this one.

To start off, I do have an extremely light seep in the rear differential, you will see where this play into the situation later on in this post.

I go in there to Canadian Tire (the shittiest auto shop in Canada) because the front differential was leaking really badly and I couldn't wait for next week which was when any other shop had availablility for.

I go in there and tell them to swap in the front differential pinion seal and they didn't have it in stock so they had to get it from NAPA.

Good enough, so, while it was being delivered to the shop I went around the store and shopped for a while picking up some odds and ends. I returned to the shop portion of the store and looked into the garage and there was the mechanic just finishing up replacing the rear differential pinion seal.

If you have been following, I was having the front one replaced. The rear wasn't supposed to be touched.

I ask permission to enter the shop area quickly so I can tell the mechanic that it was the wrong driveshaft he was doing. He pointed to the work order and the part and the stupid counter guy failed to point out that the job was for the front on the work order.

That plus the NAPA sent the rear pinion seal instead of the front.

So push comes to shove and they said they wouldn't charge me for the labor for the rear seal but I would have to pay for the part which was only $15 so no biggie.

So in the end I got both pinion seals replaced for essentially the price of one. Both are dry as a fart in a wind storm and doing well.

Weird how things go bad, but then work out to your favor.

Is this the first time you have the rear pinion seal replaced? If not, the crush sleeve needs to be replaced, I hope they looked at it anyways. Also, the pinion nut needs to be torqued to a proper preload, I hope they understand it isn't as simple as a seal change.

They just changed the outer seal.

Truck seems to be running perfectly with no problems whatsoever.

It is the first time any seal has been changed.

To get to the rear pinion seal they have to remove the pinion nut. If they tighten it too much, the bearings will burn up, if they don't tighten it enough, the pinion gear will move causing excessive play, eventually requiring a rear-end rebuild. I just had mine done also and was completely anal about having a specific person work on it because it's kind of difficult, especially for someone with no rear end knowledge, to change out that seal. This may not be the case I'm just looking out for you, you didn't seem too thrilled to begin with about the place you took it to.

To get to the rear pinion seal they have to remove the pinion nut. If they tighten it too much, the bearings will burn up, if they don't tighten it enough, the pinion gear will move causing excessive play, eventually requiring a rear-end rebuild. I just had mine done also and was completely anal about having a specific person work on it because it's kind of difficult, especially for someone with no rear end knowledge, to change out that seal. This may not be the case I'm just looking out for you, you didn't seem too thrilled to begin with about the place you took it to.

True, you are right there and thanks for thinking about my situation.

I don't know how much they tightened it but there seems to be no play whatsoever.

Now you have me worried.

Your best bet would be to contact them and speak to the tech who worked on your truck. Since the crush sleeve was not replaced the pinion pre-load needs to be matched precisely to what it was before. Ask him if he did this, and if so ask him how he did it, likely he either chisel marked the nut, or, more precisely and what I would expect any shop to do, he measured the pre-load with an in/lb torque wrench. You won't have any damage yet, but find out what is going on as soon as you can.

Wow, this has me concerned.

I honestly don't trust these guys too much and seeing they can't even get the right seal, I don't trust them to do it properly.

I know where you are coming from. When I first noticed mine was leaking I figured hey it's a seal, I'll do it myself. I got to reading up on this in my GM Repair Manual and they were adamant about how important it was to have the proper pinion pre-load. Give them a call tomorrow and see what they have to say, who knows, maybe the guy who did it knew what was going on.

I know where you are coming from. When I first noticed mine was leaking I figured hey it's a seal, I'll do it myself. I got to reading up on this in my GM Repair Manual and they were adamant about how important it was to have the proper pinion pre-load. Give them a call tomorrow and see what they have to say, who knows, maybe the guy who did it knew what was going on.

I hope so. I just took it for a test drive to check things out, went for a good 60 miles or so.

Tell me, is it normal for you to hear a light whirring noise when in 4x4 at highway speeds?

If your Blazer isn't full time 4wd crawl under and see if the front drive shaft spins freely.
The reason why I say this is because I once never thought of disengaging my posi lok (cable replacement for the vaccum operated system) and had a whirring noise.

Further discussion about the 4x4 whirring noise can be found here:

http://www.automotiveforums.com/vbulletin/showthread.php?t=576727

Just as an addition, they didn't have a front pinion seal in stock when they made the mistake but they said they "found on that would fit" which by the looks of the part number is the rear pinion seal.

Here is what I think happened.

1.) Guy gets the work order which doesn't state which seal, gets the front seal from NAPA and installs it in the rear differential.

2.) They state for some reason they got sent the rear seal when in actuality they got the front and installed it in the rear.

3.) Thinking that it fit, they then get the thought that the rear seal is the same and installs a rear seal in the front differential seeing they don't have a front seal in stock and had it ordered in from Napa, but they installed it on the rear so they think they are the same and put a rear in the front seeing the part number and the price is from their rear pinion seal listing.

Is the front and rear pinion seal the same? I got 1 1/2 hours sleep last night thinking about this and I am going to have to get them to set it straight when the store opens.

Any thoughts guys?

SComp23 is correct, it is absolutely crucial to get the preload torque right. If not it can mess up the bearings and/or cause a misalignment of the gears and cause damage like what is shown in the pictures below. The pictures below are of my rear differential, the damage was caused by a misalignment of the gears caused by the cruch sleeve giving under load.

These are pictures of the ring gear:

http://img12.imageshack.us/img12/4697/ring2ea.jpg

http://img12.imageshack.us/img12/6170/ring25uy.jpg

http://img8.imageshack.us/img8/3384/ring32bk.jpg


This is what a pinion gear is suppose to look like: :biggrin:

http://img80.imageshack.us/img80/2875/pinion3nr.jpg



Here's what mine looked like: :icon16: (notice the missing teeth)

http://img12.imageshack.us/img12/4368/pinion26bl.jpg

Going by the part numbers at rockauto.com, it looks like they're the same.

Now just thinking the worse case scenario, if he didn't do it properly and now doesn't have the original placement, how do they get it back to spec?

This is if he didn't mark where the nut was nor did he take a inch pound reading on the nut itself.

How would they know now that he doesn't have either for the baseline to adjust it back to?

That is when, I believe, they replace the crush sleeve, and that sets the proper pinion pre-load.

If he under torqued it you may get away with tightening to the proper preload, but you may lose some life on the bearings. If he over torqued it, it will have to be pulled apart and the crush sleeve replaced. The new crush sleeve needs to be set-up correctly because it is what keeps the proper tension on the bearings.


Edit: I found a site with pictures and pretty good explainations.

http://hotrod.com/techarticles/84118/
.

welp, I got back.

1.) The manager was being a prick. Said there was no front pinion seal. I laughed literally.

2.) Asked me if it was leaking like if it isn't leaking no biggie then.

3.) Said he would call me when the parts comes in, this is where I told him it was at Napa, he can order it and have it here in 20 minutes, he then paused and acted puzzled and then knew I wasn't going to be blown off.

4.) Talked to the prick mechanic that did the job in the first place, I asked about him preloading the bearing and he said that he made a mark for reference and he did torque it properly. WHEW!

He was an arrogant bitch and scoffed as he entered the garage portion again after talking to us.

5.) They had me wait 4 1/2 hours before they did it, one hour was me waiting for the second mechanic in line seeing the next one up was the moron that fucked things up in the first place.

6.) I went to the part department to get a look at the rear seal for a comparison and also went to the dealer, they are different seals. The rear one has a bead of rubber around the edge for the outer seal, and also had an inside diameter 2mm wider. These are NOT interchangeable. Not in this case at least.

7.) Walked out of the shop with new pinion seals properly installed on both differentials for CDN$117 total. Not a bad price if I say so myself.

They didn't charge me anything for the replacement.

Also, the second mechanic was really easy going and cool. I told him what happened so he didn't make a mistake and just replace what was there with the same thing without the swap.

Also asked him about the preload and he said there was marks from the moron but he etched some marks in the metal for future reference.

Also he said the crush washers are good for 2-3 seal replacements which was referenced as being true by the dealer.

So in the long run.....I WIN!!!!!!

Your help is amazing guys, I won't forget it, I am MUCH happier now. :D

When they finally handed me the keys back the counter monkey handed them to me and turned his back and talked to one of the other employees.........I got the last laugh when I noticed what he was doing, laughed out loud because it was obvious (other customers noticed) and walked out to never grace a Canadian Tire Auto Shop again..

I'm glad to hear that you got it taken care of. A lot of people just let places like that walk all over them, and never do anything about it.

Now just thinking the worse case scenario, if he didn't do it properly and now doesn't have the original placement, how do they get it back to spec?

This is if he didn't mark where the nut was nor did he take a inch pound reading on the nut itself.

How would they know now that he doesn't have either for the baseline to adjust it back to?

http://www.differentials.com/install.html

http://www.differentials.com/specsi.html

MT

I'm glad to hear that you got it taken care of. A lot of people just let places like that walk all over them, and never do anything about it.

So true, I think that is what he was trying to do with his "Are they leaking?" question.

Sure they won't be leaking now, but what about in 6000kms when the warranty is up and I am a square one.

I don't settle for acceptable right now. I want the job done perfectly and he knew it.

The idiot that did it won't go far in his trade if he can't even get this small, 30 minute job right.

Demote him to the oil change station.

Glad everything worked out LT, I'm the same way you are when it comes to stuff like that, I need to make sure everything is done right. I'm the kind of guy who talks the the mechanic every hour for an update :D

Glad everything worked out LT, I'm the same way you are when it comes to stuff like that, I need to make sure everything is done right. I'm the kind of guy who talks the the mechanic every hour for an update :D

You do know we are their worst nightmare.

I love it though, I am so neurotic about the repairs seeing like this situation, if I sluffed it off, they would have gotten away with an improper job done.

Exactly, if it wasn't for the anal retentive people like us, imagine the quality of work you would be seeing out of some of these places. I don't try to insult anyone's intelligence, I just want to make sure my truck doesn't fall apart for something that is out of my hands.

Exactly, if it wasn't for the anal retentive people like us, imagine the quality of work you would be seeing out of some of these places. I don't try to insult anyone's intelligence, I just want to make sure my truck doesn't fall apart for something that is out of my hands.

So true.

He would have gotten away with a horrible job.

I don't know why I accepted it like that lastnight.