[dataway]

What do you guys think of the whine in this boring first drive video?

https://www.youtube.com/watch?v=sjt4EtVkiNY

Rear end is an untouched unit original to the car, 110K miles, all I did was change the axle bearings and change the fluid. It's a 2.93, non-posi. It sat inside/outside for 40 years fully assembled so I'm sure there was some condensation in there. I did not see any issues when I had the cover off. I did do some considerable banging and pulling to get the axles/bearings out.

Bought the car in 1976 .... don't remember it ever making this whine.

Also when this video was made the TH400 was 1- 1.5 quarts low. The trans is original to car, I rebuilt it, shifts fine (although a bit early), kick-down works, seems to function fine. I'm no trans expert but it doesn't really sound like a pump whine to me.

Any ideas?

[steve25]

Is this whine all the time, or does it only start once a certain road speed and or rpm is reached?

With the car rolling if you place the trans in neutral is it still there?

With the ass end jacked up and the motor idling in gear can you grab one wheel or the other and then the whine stops?

[JSchmitz]

Start by topping off the trans and power steering pump if you have one. Does it get quiet when you let off of the gas or is it constant? Louder in gear vs. neutral? Check differential fluid also. Been sitting a very long time sounds like? Do some fairly hard turns or jack each side of the differential up to make sure some lube gets to the axle bearings. Seems pretty loud. Should be able to narrow it down.

[dataway]

Whines all the time while moving, any/all speeds, changing tone from acceleration to deceleration. Whine increases in pitch with road speed.

I'll check today if it's still there in neutral rolling.

Diff fluid was changed and topped up, just checked it, still topped up.

Engine/trans/accessories are quiet as a mouse when stationary, in gear or neutral.

I'll try jacking up the rear if the other things don't tell me anything.

[dataway]

Took it out again today. Yes the whine is still there coasting in neutral, but it does change in tone. So it basically makes three different noises .. acceleration, deceleration, and coasting on the level.

Topping off the trans fluid made no change.

I'm guessing I buggered something up when changing the axle bearings, or just sitting for 40 years compromised something in the diff.

At least it doesn't seem to be getting worse, might even be getting a bit quieter.

[Holeshot71]

Any chance the brakes or e-brake are hanging up?

[dataway]

Up on a lift the wheels all rotate nicely with no dragging, same with the e-brake.

I'm pretty confident it's in the diff. It's got that perfect bevel gear whine that's totally tied to road speed. Everything else is wonderfully quiet except a fan belt when I goose it real good.

[PunchT37]

I heard that in the vid. Best I can tell on the computer, you might have a bad pinion bearing or 2. Rust pitting might have got to em while sitting.

[dataway]

Yep, that's what I'm thinking.

What do you guys think .. leave it be and see what happens? This isn't a daily driver, or a race car ... just an "out to the drive in" now and then car.

[JSchmitz]

It does sound like differential. Might drive it a bit more and then pull the cover. Inspect gears and look for glitter in the oil. Or, alternately, crank the radio up and hope for the best.

[gto4ben]

It sounds like your pinion may be developing a radial crack causing a tooth to be misaligned. Tone changes in load is a tell tale sign. The crack starts on the bearing side and cannot be seen unless removed from the housing. Eventually, the pinion and ring gear teeth will not mesh and you'll crack a tooth. I had the same sound on a 3:23 non-posi rear end.

[mchell]

Sounds like rear end issues….I couldn’t stand that amount of noise. Pull it apart and see what’s wrong. Start by looking carefully at the bearings you just replaced…

[b-man]

On a couple of my 1964 8.2” 10-bolt rears the pinion nut worked loose. These rear ends had never been apart, I found the loose pinion nuts while replacing the pinion seal.

Once that crush sleeve loses its crush I’m guessing the nut is able to loosen and you lose the pinion bearing preload. Then the ring and pinion are no longer meshed properly and the gear whine begins.

I think it’s time to yank the rear end out and have it professionally rebuilt, hopefully before the your original gear set goes south.

[NeighborsComplaint]

I heard it in your vid. Almost like a Muncie (M22?) rock crusher trans. Probably a pinion bearing. Worn ring and pinion is possible but they are still pretty quiet off the gas when coasting and whine when your on the gas.

[dataway]

Sounds like something I should have a look at. Strange that the rear was very quiet when I drove it years ago. It does quiet down a lot when in a completely neutral coast ... meaning no engine braking, no acceleration.

Hard to see in the video but I'm going up and down some decent grades. Up on a lift in Park the spiders at least feel very smooth and quiet.

I'll check the pinion nut soon as I can.

[dataway]

So I was under the car for a while looking at the rear end. Externally nothing amiss, no leaks ... still has the OEM pinion seal. When rotating a wheel in neutral so that the driveshaft turns (brake dragging just enough on one side) I do hear a slight tap every maybe 180 degrees of driveshaft turn, not present unless the driveshaft is turning. Also a very small tick in the spiders when driveshaft is stationary and the wheels are turning opposite directions. Nothing really that would jump out at you as impending disaster. There is some slop, but an amount I would consider normal for a 100K rear end.

Did have the brake on one side dragging a bit, but still able to turn by hand without a lot of effort ... but enough to stop it from freewheeling. Adjusted that.

I see a teenie tiny bit of slop between the yoke and the pinion nut, if you get REAL close you can see what appears to be the yoke moving a fraction of a degree before the nut turns ... assuming that is just slop in the yoke splines? Such a small amount I was thinking it was my imagination.

Going to get some diff fluid and a new gasket and look inside ... don't expect to see much as I cleaned out the pumpkin when I replaced the axle bearings and it's got maybe ten miles on it since then.

[Held for Ransom]

Did you use conventional or blended (synthetic) gear oil?

[dataway]

I used conventional, valvoline. It was the standard 70-90wt I think.

[dataway]

Correction ... I used Valvoline synthetic 75-90.

[Held for Ransom]

Personally, I've never been a fan of the synthetic blended. Try to drain and fill with conventional 80W-90. Last time I needed it, I was able to purchase Valvoline SAE 80W-90 High Performance at my local Fleet Farm.