1994 Camaro, 3.4L V6, Auto, 160k miles.

Driving home from the airport last night at about 70mph, I started hearing a terrible grinding noise. A few minutes later, I exited the highway and started seeing smoke. At one point it even started coming into the car through the dashboard area. It was pouring out from the engine so badly that I thought the car was on fire, and stopped and pulled off the side of the road. After realizing there was no fire, I figured I'd limp home... but the car was VERY hard to start, it just didn't want to turn over. Finally came to life and I made it home.

1) Grinding noise while in motion, seemingly coming from back end somewhere
2) Worse when giving gas on the highway, dropped in volume when I dropped back down when coasting-in-gear
3) Worse in reverse than forward
4) Happens when in neutral, too, forward and reverse.
5) Car started up normally right after I got home, and again this morning.
6) Oil, Transmission fluid, brake fluid and power steering fluid levels are all fine
7) The smoke was diffuse, coming out from both sides of the car, and the source looked to be somewhere behind the engine. No smoke was coming from behind the car, but that may have been just the wind.
8) The smoke was white and smelled a little plasticky, and almost like like power steering fluid.
9) It sounded rather like I'd imagine if all the oil had drained out of my engine. But the oil pressure stayed normal, and the oil level and color is great.

I may have multiple issues here, I suspect the starting problem is unrelated, and I have another (also probably unrelated) problem with vacuum on the intake manifold.

There's also something wet all over the bottom of the bottom of the back-end of my car. Not sure if it originated there, or was just splashed up.







What's most likely broken? What should I check next? The grinding sounds like a differential or wheel bearing issue, but doesn't explain the smoke, which I'd expect to see from the back of the car if the dif was spraying oil, and not from the engine/transmission area. I thought after it failed to start right that maybe the starter solenoid stuck and I burnt up the starter, but it's been starting fine.

 

i see your leaking oil, what color is it? need to figure out if its trany (red) or motor oil (green,brown,black). sounds like the trany but u need to confirm.

 

It's the color of motor oil, but has the same burnt smell as my transmission and power steering fluids... maybe I should change them at some point, too, lol. (Done two coolant flushes, but I've never changed either in the 70k miles I've put on the car. Brake fluid, either.)

What color is differential fluid?



Edit: it's hard to see here, but the oil color looks good, lots of amber in it still (only been about 1000 miles since last changed), and the power steering fluid is a different color than wiped from underneath the car. The engine oil is a clear match.

 

It looks like your pinion seal on the rear differential is leaking badly, and slinging oil on the exhaust pipe causing your smoke. A low oil level in the rearend will then make the ring & pinion gears "sing", and your wheel bearings groan.

 

At least it's not a blown head gasket. Do I have to remove the rear axle to change the pinion seal?

 

You may need some new rear-end bearings...

 

No, you don't. Lock the e-brake, unbolt the rear u-joint (4 bolts), drop the rear of the driveshaft, brace the pinion with a long bar to keep it from spinning, and remove the pinion nut. The nut is on with around 200 lbs. of torque (and many years of corrosion), so it's not going to fall off....it's tight. Then the pinion will slide off and you can pop out the old seal.

 

Awesome! Finally, the excuse I need to buy an impact wrench!

Which bearings do you mean, libertyforall, the pinion bearings? While I've got it apart, I'd like to check all the gears and bearings for damage. What should I look for?

 

Chilton is saying I should check the pre-loading on the nut with a torque wrench before removing it (I highly doubt any torque I get would be accurate of the factory preloading at this point) and also saying a special tool is required to insert the pinion seal. Are those steps necessary, or do they just make the job easier?

And am I risking rolling my car off the ramps by wailing on this nut with that much torque?

 

i think camaro is talking about just changing the seal. its a big job to replace the bearings in a rear end. very tedious and spacific. if you think the bearings are gone personlly i would change the entire rear end with a good used one and be done with it in a day. i think your looking at 150. to $250. look around, at the local yards and on the for sale threads on this site and any more you know and see if theres someone close that has what you need and go have a look see. in time i will be going with 12 bolt strange with 373 gears but for now the stock one will have to do.

ps if you want to change the seal you will be taking the yoke off. to stop from spining u can put a pipe wrench on the yoke (outside do no damage to were the ujoint goes) and a cheater bar on the pipe wrench. aways block the tires.