GASGZLR

On friday I was driving home from work in my 89 Camaro (5 speed, stock) and my pinion seal gave out. It leaked all my gear oil out when I was doing like 80 MPH, and it started to whine BAD. I immediately started to stop to let the rear end cool but at the last 30 feet of my stop the gears stopped whining and started GRINDING! I let them cool for about 20 minutes and tried to drive a block to see if they would do any thing. They were quiet unless I went above 30-35 MPH, so I drove home at like 25-30 with no problems. This weekend I changed the clutch on my car and since I had the driveshaft off I changed the pinion seal too. When re-installing the yolk I tightened down the big 1 1/4" bolt as hard as I could with a 9 inch ratchet and topped it off with gear oil. Now when I drive it, it's fine until I get to around 50 then when I am coasting/maintaining my speed it whines noticably. It does not whine when I am picking up speed or downshifting to slow down, only when I get to around 50 and barely put my foot on the gas pedal. Did I tighten the pinion too much/ not enough? Maybe ground some material off the teeth when it ran dry? It's very annoying and need to fix it.

RB83L69

Run dry = trashed everything in it that moves

I'd start looking for another rear. That's going to be alot cheaper than repacing all the gears and bearings in a smoked one. It usually isn't even remotely near economically sensible to repair a common rear like these from a total destruction like that.

GASGZLR

But it runs fine now, NO grinding and it is real smooth except for that little whine. If I blew everything, shouldn't it grind and seize up and not even drive???

GASGZLR

I am doing some reading on the forum, and so far a lot of people are saying that I might have not put enough pinion preload on my bearings and that it's causing the pinion to move back and fourth slightly. Does anyone know if this is true? and can anyone tell me if there is a torque spec on that pinion bolt. Thanks

EDIT: I used 80W-90 gear oil in it.

Bandit5

Pal, I did the same thing, and he is right, everything in there is ****ed.


I blew my pinion seal in my Moser 9" while travelling at excessive speeds. I drove it home, replaced the seal and filled with oil, now it whines incredibly loud. The only thing I can do to combat it is turn up the stereo. You are going to have to replace all the bearings and the gear set. This is a good time to do any gear changes or posi-swaps you were planning on doing later.

My car runs fine now save for the noise, but I am goign to get it rebuilt. I am praying my posi unit survived - since both wheels still spin, I think it is ok.

GASGZLR

That's not what I wanted to hear, Bandit5, but thanks for the input. What will happen if I just keep driving it around? Will it just whine forever?

RB83L69

It will continue to get worse until finally some critical part gets ground all the way to powder and then you won't be able to drive it any more.

Feel free not to believe me, and find out for yourself. It doesn't really matter whether you get another rear end now or save it for later, except that at least now you sort of have control over when you're going to replace it. You may not have that luxury for much longer if you continue to drive it.

TKOPerformance

Yeah, and hope that it doesn't fail catasrophically when it inevitabley does let go. If the pin drops out of the case it can lock the rear up. At the very least this will junk the rear, probably flat spot both your rear tires, and cost you a tow bill. At the worst you will lose control and could have an accident.

Unless you want to beef up the rear I would agree with RB83L69 and say just find a good used rear. You can usually pick them up for about $150 at a junkyard. That doesn't even cover the cost of a new gearset.

GASGZLR

It doesn't wine that bad and not all the time, so maybe they will last me a while cause this car is my daily driver for gas milage and if I replaced the rear end gears it would be with stock ones, or worse than stock ones like a set of 2.73's that came out of my 90 that are now a decoration on the chest by my bed. Should I pull the cover to see if the gears are damaged?

TKOPerformance

The whine is most likely not even from the gears. It's probably a bearing, or bearings. All the bearing and race metal that ran through the rear when it ate up the bearings from running without oil has ruined the gearset. Trust me and everyone else on this board. The rear is headed south in a hurry. It won't get better if you just ignore it. If you fix it now it could save you a lot of money in the long run.

Petes 84Z28

Don't count on it. This has happened to me twice. First time was in the Z28, everything locked up solid when the pinion shaft bearings seized up. Second time was in my 81 T-bird; one of the side gears disintegrated - the driveshaft would spin but wouldn't power the wheels. No warning either time.
Best (read:cheapest) solution is to acquire a replacement axle and swap it in.
The whine you hear is the bearings and their races...they got hot enough to lose their hardened sufaces, and are slowly wearing themselves to death. Soon go boom.

GASGZLR

OK I am convinced that I will need rear end work. Should I buy new gears or put in the ones I have, or just get a whole new rear end from a junk yard? Remember this is on my daily driver so it does not need to be sooped up or any thing it just needs to run reliably.

LilJayV10

iTrader: (5)

First thing i'd do is get the car up jack stands then run it in gear and take a stetoscope(I know i can't spell) and have someone change the speed of the car untill it whines, then check the outer/inner bearings, and pinon bearings. if its a bearing you will be able to hear it howling. If you can't hear a bearing howling, then take off the rear cover and look at the gears and check to see if there is any metal in the bottom of rear end. After that, if every thing looks ok put the cover back on and put new grease in it, maybe sythentic wouldn't hurt, then re check your pinon, the way my boss does it at work is by feel, he has been a mechanic for 40 years so he can do that, I tried it and, well he finished the job, there should be drag on the pinon when you turn it, it can be measured in foot lbs, if you have a cheap tourqe wrench, the kind with the pointer, you can see how much drag is on the pinon, ( i can't remember how many foot lbs)the more you tighten it up the deeper the pinon runs in the ring gear. check these things first.
All the bearings could be trashed, maybe one or two, if the gears are ok, I'd seriously consider replacing the bearings that are bad, they aren't real expensive. Depending on if you have posi and what gears might play a part in wanting to keep what you have and fix it. If the whole thing is trashed and you have an open 2.73 it might be easier to grap a rearend out of the junkyard, however you don't know the condition of the rearend you are getting. If you replace whats wrong in your rear atleast you know exactly what you have. I have seen alot of cars at work that "should have" broken or ruined this or that part but it doesn't always end up being that. do some checking before you start yanking the rearend out of your car. For every story someone gives you about, oh yeah man the same thing happened to me and it was junk, there are just as many stories saying yeah i did that, i got lucky and fixed it. Always check first.
Jason

TKOPerformance

Considering that you will need at a minimum every bearing and race in the rear, plus all the setup parts; I would say go with a good used rear. If your goal is dependable and stock that's what I'd do.

GASGZLR

I plan to pull the diff cover and see what has happened. I want to see if there is actually shavings or damage. If all looks well I will try to tighten the pinion a little more. It couldn't hurt to check the wear pattern with some marking compound to see where it's at. With the driveshaft disconnected and the wheels up in the air I will rotate the pinion to see if it has any resistance on it and also some end play.

Q: If bearings were bad wouldn't the rear sort of grind all the time especially with load on it, as in accelerating?

RB83L69

Again, not to be a pessimist, but....

I doubt you'll have to use marking compound to see the wear pattern.

Looking at the parts before jumping to conclusions is always a good idea. But I don't think you're going to like what you see when you open it up.

GASGZLR

Ouch RB83L69! That marking compound comment hurts. You are probably right I don't want to see what's under there, but I have to know. It's kind of like looking up your grades for last semester in college, you know it's not going to be pretty but you have to do it.

GASGZLR

...but my dad found a guy who says he has a rear from an 89 Z and he would probably let it go for like 50 to 100 bucks. I don't want to replace the whole rear if I don't have to but should I get it anyways just in case?

RB83L69

I wouldn't, unless it's a 9-bolt....

Always use things like this as an opporunity to do an upgrade. I mean, if you have to buy something anyway, why not buy something better than what came out, instead of the same or not as good? Especially somehting not as good; why spend your money to make yoru car worse? That doesn't make sense.

So here's the logic tree. Keep in mind, your car probably has a 3.08 now, and if I know 3.08 gears, you're not real happy with it.

If it's an IROC, it's probably a 9-bolt, and none of the parts will interchange with your car. However it will have the PBR disk brakes, which is a good thing, by itself. But its gear ratio will most likely be no better than what you've got, and maybe worse. Only a good idea if you want good brakes, but don't plan on upgrading the gear, because that's comparatively mega$$$ in a 9-bolt. If it's a 5-speed G92 car, it probably has a 3.45 gear. That's probably the most sought-after 9-bolt. A 350 G92 car would have a 3.27. Either of those would be a great deal. If it was a non-G92 350 or a 305 auto, it's a 2.77; if it's a 5-speed non-G92 it's probably a 3.08. Most likely it's the 2.77 or 3.08. If it's one of those, you probably don't really want it.

If it's not an IROC, but rather just a Z28, it's probably a TBI car, and will be a 10-bolt with the same ratio you have or worse. Definitely the wrong way to spend your money.

So, in either case, it's not a clear-cut winner, unless the 89 Z28 was a G92 car. I'd keep my money in my pocket for the moment if I was you.

If it turns out that your existing rear is toast, the best thing to do would be to go to the junkyards in your area, and look around for 90-92 6-cyl 5-speed Camaro and Firebird rear ends (don't bother calling on the phone). That will be a 28-spline unit with 3.42 gears. All around an upgrade to what you have. No posi, and drum brakes; but you could stick the $99 posi from SLP in it and fix that.

GASGZLR

The only thing is I need to fix this car soon to go to work. Today I brought the "Beast" (90 Vortec) and I can't keep filling up the tank every two or three days. I am just looking for something to get my 89 running, and although it is tempting to put 3.42's or 3.73's in, I am going for max economy. Even if I have to put a 2.73 or 2.77, that would get me better milage.

BTW: Didn't chevy discontinue the "Z28" model in 87 and go to just having IROC-Z's for 88-90? I never heard of a Z28 in 89. I have seen a TBI 89 IROC though.

GASGZLR

I pulled the cover and saw a tiny amount of shavings on the magnet. The bearings looked fine were still tight, and the teethe of the gears weren't worn that much at all-looked like a good rear. I drained all the fluid AGAIN and used some carb cleaner, and a magnet to spray down the gears and clean everything out. No shavings were on the magnet at all. I let it all dry then I put the cover back on and filled it with 80w-90. I also put in a small tube of graphite in the oil. I loosened the pinion nut and readjusted it. Now it runs fine and the whinning is less to where you have to be listening for it at 45-50 MPH all other speeds it is quiet. My grandpa was a mechanic for FOURTY years and he told me to put a little graphite in the oil to smooth things out. He said it should last me like that if I can live with a little whining.

TKOPerformance

Just because you didn't get a lot of metal out doesn't mean that no damage was done. The problem is the heat that the bearings and races absorbed. Did you disassemble the rear and inspect each bearing and race? Unless you did that I find it hard to believe that nothing was damaged. Most likely the races will be discolored due to heat (Iblue or brown) and the center part of the race will be a dull silver. There may be slight galling, small pits, at this point, but it hasn't been run long enough for the material to really start to rip off the surface.

Do what you want, but don't be suprised when it grenades.