W30Olds

I have a 70 442, all original drivetrain with a 3.23 anti-spin 8.2 rear. The rear has a notable whine which gets louder as the speed increases. The fluid level was low when I bought the car, since then I've changed the rear fluid on it using 80w90 and posi additive with no change in noise. Most recently, at a stop sign or red light going to make a turn I've been noticing the car vibrating and having a clunking feel when making the turns at low speeds at about 5-10 MPH. Does anybody have a idea of what is causing these two problems?

Here it is without the cover, picture taken directly in the middle of the carrier.

oldsmobiledave

no such thing as an original numbers matching 8.2" rear end for 1970. It is an 8.5" Type O 12 bolt.

507OLDS

It sounds like the pinion is too deep into the mesh. It is possible the the pinion is loose,therefore pushing itself deeper,causing the noise & making the clunk sound.Put your hand on the yoke & see if you can find any play or slop in the pinion.

Sugar Bear

Does the whine change if you are cruising and lightly accelerate and change again when coasting? If yes it may have bad pinion bearings from being low on oil.

The "chatter" on slow turns may be worn clutches due to low oil. The additive can take a while to work into the clutches. Get the car thoroughly warm on an interstate ride and then go to an open area and slowly do figure eights to the left and right to work the additive into the clutches.

W30Olds

Thanks for that info, I'll have to try that.

As far as the whine, it only gets louder with speed, so it has the same whine at 40 MPH no matter how long I stay at that speed. If i put the car in neutral from drive at 50 MPH, the whine considerably disappears.

Also why can't I see the bearing race in the hole on the passenger side of the pumpkin? I assume I should see both of them through those holes.

Fun71

The bearing race is underneath the cap, not out there by the hole.

507OLDS

Still sounds like the pinion is too deep,or is loose,and getting pushed into the center.
Whether the bearings are bad,or the pinion nut is backing off,it only needs to move a hair for it to make noise.

monzaz

That rear is a 12 Bolt Olds 8.5/ 8.4 I like to call it. (as stated in the second post)
The noise on turns is clutch chatter you need Posi / limited slip additive and an oil change. (if you have the know how you can tear the posi down and check the clutches if you want to see how much swirl the clutch surface has left and re-shim the clutch pack)
Gear whine - IF the set up is original from the factory.... probably what Brian mentioned pinion nut slightly loose. We say this because if it were a bearing it would likely have the whine on accel and decel and pitch change at speeds and be more of a whirl noise.

BUT that does not mean it is NOT a bearing either. (everyone have a diff description of noise. )

It could be Backlash also. IF someone ever had the rear apart for some reason they could have put the carrier shims on the wrong sides... If you can get a magnetic base dial indicator on the ring gear tooth and rock the ring up and down and see what the distance is between the coast and drive side contact of the ring and pinion. If you can get some marking compound put that on the teeth and spin it around and around both ways and shoot another picture of he pattern for us.

Till then check your pinion for up down in out play. ANY AT ALL IS bad... Spinning is all you want . ALSO check your u-joints for any play too hold the yoke and twist the shaft if you get any slight movement in the joint it is junk too.
Jim
JD

Steve g

Gear noise or bearing noise?

Generally speaking, but with great reliability;
Bearing noise is not best described as a whine. It is more a low pitched drone. It starts right as the wheels start to turn although you may not hear it until a bit faster. It increases in volume and intensity the faster the vehicle goes. Direct corelation to vehicle speed. The faster you go the louder it gets. It does not go away backing off on the pedal, moving the gear contact from drive to coast.

Gear noise, on the other hand, is a distinct higher pitch whine. It is not directly related to vehicle speed, but rather will usually have a "hot spot", a point at which it is loudest. It will diminish above that point or below it. Because gear whine originates at the tooth contact, backing off the throttle and moving the tooth contact from the drive side to the coast side or to the float position will cause the noise to disappear or significantly change pitch.

A loose pinion will not make noise in the forward load position unless the looseness is caused by a catastrophic failure of the rear bearing (extremely rare). If the looseness is caused by a loose pinion nut (very common) or or catastrophic failure of the frt bearing, forward loading (driving) pushes the pinion forward and takes up the slack and placing it in it's normal position. When you back off and reverse the load the pinion walks inwards and is then out of adjustment to the crown and will make noise.

Failed bearings causing noise will not necessarily cause looseness, and in fact seldom do. It takes a catastrophic bearing failure to display looseness. The bearing failure is usually pitting in the race surface from the case hardening starting to come off.

How to find it? Block the car up off the ground. Check for obvious looseness in the pinion. Run it in gear. Take your mechanics stethescope with the metal probe on it and place it directly on the housing where the bearings run. Good bearings heard through a stethescope will make a whirring sound. Rough bearings will make a rumbling sound. You don't need to be at speed to detect the difference.

I'm sure I'm forgetting something. When you've been doing something long enough it becomes automatic and you no longer think about every step and every reason.

Steve g

507OLDS

No. It will drive it into the ring,under load.If it is loose.It will get pushed away during coast.

Steve g

Backwards. Go try it. That's why the big bearing is on the rear of the pinion and the small one on the front.

Steve g

507OLDS

I know what you are saying.It's a giant LH thread,and you are turning it clockwise,but when they have been loose,they seem to get pushed into the ring when under load,and get kicked away when coasting.Makes sense with the bearing placement too.Assuming that those gears are original to the housing,and nothing has been changed,to make a noise like that,with a loose pinion,it would be pushed into the ring,simiulating a pinion that is set too deep.The noise goes away during coast.

Is there any evidence of it ever being apart,like a pinion seal replaced or anything?Just maybe,it had a bad seal,lost some oil,and the seal was replaced.The nut was not tightened properly,and the oil was not added. Just a thought.

Steve g

Brian, I'm not going to debate this or try to convince you, but any one that wants to take the time can see for themselves. You are wrong. The pinion walks forward under forward drive. The engineers put a big bearing facing forward into the housing to carry the biggest load, forward motion. You can take the nut off and make it drive forward as hard as you want you won't hear a noise and the pinion will hold tight. When you back of, or put it in reverse the pinion walks in. Seen this so many times I can't count it.

I may not have installed 8.2 or 8.5 gearsets numbering in the 3 digits, or the thousands like the guy on the assembly line, but I spent a good part of my career diagnosing driveability complaints and noises. And to do that best, you learn how things work. I know which way the loads travel.

Steve g

507OLDS

What I am saying is that I have seen some situations where a pinion nut was not properly tightened,or came loose,and the rear made the same sounds as he is describing.Like when a pinion is buried too deep.The problem was solved when the nut was tightened.I am giving the guy a place to start,based on what I have seen.Yes,the bearings could be cooked,and it could be that,or something else.Let's just hope that the gears did not try & recut themselves,as then they are ruined,and O-axle gears are scarce.
I am not on here to match wits because frankly,nobody cares,and I am next to impossible to impress.

Steve g

Hey Brian, let's not get off in that direction. You attempted to correct my post.
"No. It will drive it into the ring,under load.If it is loose.It will get pushed away during coast. "

Your correction was wrong. Anyone can go in their shop and confirm that for themselves. It's not subject to interpretation. I don't think backing up my post and showing that it was not wrong is an attempt to impress anyone, least of all you.

Yes, a loose pinion nut will seem like a deep pinion, in a coast situation. At coast the pinion is drawn back into the ring gear. In a forward acceleration it is pushed forward against the back bearing and is sitting exactly where it was when set up. Hence no noise on forward acceleration.
Now I'm not saying you didn't experience a pinion that worked the other way and I'm all ears to hear about anything that is counter to the numerous loose pinions I've seen and defy all logic.

Nuff said.

Steve g

507OLDS

If it was loose,and it pushed it out during load,then why would it make noise when even the slight amount loose,but not when torqued or preloaded properly.If it was pushing out,the pinion depth would be the same.However,something is changing it,and from what I encountered,the pinion but was loose.

Steve g

When you are accelerating forward, even lightly, there is a huge amount of force pushing that pinion forward. Try this in the shop. Back off, or loosely install the pinion. Use something to lock the ring gear. Now turn the pinion in the forward direction and hold pressure on it. While holding forward twisting pressure on the pinion, try to rock it back and forth. You can't move it. Lighten your twist on it to the coast situation it will rock, turn it backwards and watch it pull in to the case. The forces pushing it forward are huge and increase with how hard you load the gear set. Under accleration that pinion is pinned forward.

There are 3 relationship situations ring and pinion exist under, drive, coast and float. When you are cruising, even though you are not consciously moving the throttle up and down, the momentum of the car, the road surface, the wind etc all cause the gears to move continuously through those 3 situations.

So when diagnosing a noise like this you accelerate hard and listen for the sound while it is accelerating (constant drive pressure). Then you lift your foor right off and listen as it slows down (coast) and note the noise when the pressure is in that direction. You've now moved the pinion in both directions and loaded each bearing seperately.

Steve g

507OLDS

Yes,I understand all if that,but from what he said,the noise increases as his speed increases,so he is still accelerating or placing load on it.At the point of float,the sound changes,and during coast,it quiets down.
We don't even know if the pinion is loose.
For all we know,someone could have transferred those guts,and the pinion is set too deep.

Steve g

Right. I didn't say he had a loose pinion nut. I went through the sequence of checks and diagnostics and the reasons for them. I never even hazarded a guess, but if I did I would say that he has a bad bearing. Not uncommon for someone to describe any noise from the diff as a whine. The constantly increasing tied to the vehicle speed, the fact that he can only make it diminish somewhat taking it right out of gear are all classic symptons of a bad bearing. The noise an incorrect pinion depth makes is very load sensitive. You can practically play a tune feathering the accelerater. The tone changes from drive to coast. And as I said, you will find a "hot spot" where it is at it's worst.

A steady drone increasing steadily with vehicle speed that doesn't go away or change if you back the throttle off is almost certainly bearing.

Steve g

507OLDS

The stuff I have listened to with bad bearings made a considerably different noise,but his description of a whine,might be different than mine.
As far as a deep pinion finding a sweet spot and going quiet,under load,I've never witnesses anything like that. Once it's singin',it's singin',unless you let out if it.

Steve g

No, I didn't say it went quiet under load. I said you can change the pitch by varying the load. Come out and I'll take you for a ride in my old Dodge Cummins with 615,000 kms on the D70 and play you a tune while we go down the road. On my old Cummins about 90 kph is the the loudest and sharpest. Over 90 and it starts to tone down. Quite noticeably. Mine's worn on the drive side and if I back out of it, it will go quiet. Coast side is fine. Even if the coast side was also worn or affected, they won't have exactly the same pitch.

This is not a hard thing to diagnose. Give me about two minutes driving the car around the block and I will tell you whether it is bearing noise, gear noise, a loose pinion or all of the above.

The difficulty here is doing it over the Internet from someone's description. In particular, the noise he describes steadily increases with speed, he makes it sound that the correalation to speed is very tight. Doesn't go away when he lifts his foot from the pedal. These are perfectly classic symptoms of bearings. Where it falls apart is he describes it as a whine. Bearing noise is more a drone.

On the other hand, gear noise is very sensitive to load. It has a point that will be most noticeable. Playing with the throttle will change the pitch. If you are real gentle and skilled with the throttle you place it in "float" and there is no noise because neither side of the teeth are loaded. This doesn't sound at all like what he has, but the noise in this case is definately best described as a whine.

Maybe the description is off from my nomenclature. Maybe he has both. I'm thinking we are describing the noise differently.
Steve g