Rear Axle: Differential whine

[Drifter22]

[JimC]

What gear ratio do you have? I'm guessing it's a Dana 27, correct?

I'm afraid I can't be a whole pile of help, but I will say that mine has a pretty considerable whine under load as well, but it doesn't seem to affect performance. I've owned mine for a year with a lot of miles on it, and it's never had problems. It's annoying as heck to listen to though, so if anyone knows a way to make it stop, I'll be as interested in hearing as you are. Especially if I decide to try something silly like drive it to Colorado Springs this summer.

[thunderations]

I've had 9" Ford gears that whined under load. We totally rebuild the rear with new bearings and it still whined, just at a different speed. I was told that the bearings wear and the gears wear with the bearings. Putting in just new bearings won't fix worn gears. Adjusting the backlash and every other adjustment know to man just changes the speed the whine is the loudest. I'm guessing that the ring and pinion have worn and this is your problem. It usually is not a problem other then the noise, unless there are chipped teeth or a bearing totally failed and the ring or pinion were damaged. I finally got a new set of gears and fixed the problem, but the other solution is a louder radio.

[JohnM15]

Probably worn gears but you should verify that it is adjusted correctly. Buy a tube of Persian Blue. This a blue colored grease that you put on the gear faces to check the interface pattern. You drain the oil, take the cover off, apply the Persian Blue and rotate the drive shaft. I jack up both rear wheels and use the engine to rotate. If you apply the brakes while rotating you can simulate a load on the gears. Your manual will show what is the correct pattern but in all differentials you want the interface pattern to be in the center of the ring gear teeth. The noise is usually caused by the pinion sliding off the edge of the ring gear teeth. To adjust the pinion depth and differential carrier side to side movement is adjusted with shims under the bearings. This is also how to adjust backlash although backlash is much less important than a correct pattern. With worn gears it will be not possible to attain correct backlash, correct pattern, AND low noise. If the pattern is acceptable then you can just live with the noise. You can also use a thicker gear oil. 140 weight mineral oil (NAPA) might help. I have heard that Valvoline full synthetic is the way to go...

[blackhawk61]

Red Line Diff lube will probably stop it from whining

[Drifter22]

Yes, it's a Dana 27 with a gear ratio of 3:07. Thanks a lot for your reply's.

[SN-60]

I have been restoring my 1962 Lark 4 door sedan. I had a machine shop rebuild my 259 V8. I’ve been working off and on for a couple years. I took the cover off the differential and washed it out with diesel installed new seal and gasket and filled it with Torco 85W 140 Racing Gear Oil with GL-6. When I finally drove it the differential whines. It just does it under a load. If you let off a bit it stops or slowing for a stop. I really don’t remember if it did it before I worked on the differential or not, it’s been 4 years. It didn’t look like the oil had ever been changed, but the gears look great and not much back lash. Anyone know what would cause this? I don’t think this normal. Any ideas?

Nice looking '62 Lark!

[53k]

I have been restoring my 1962 Lark 4 door sedan. I had a machine shop rebuild my 259 V8. I’ve been working off and on for a couple years. I took the cover off the differential and washed it out with diesel installed new seal and gasket and filled it with Torco 85W 140 Racing Gear Oil with GL-6. When I finally drove it the differential whines. It just does it under a load. If you let off a bit it stops or slowing for a stop. I really don’t remember if it did it before I worked on the differential or not, it’s been 4 years. It didn’t look like the oil had ever been changed, but the gears look great and not much back lash. Anyone know what would cause this? I don’t think this normal. Any ideas?

Could be as simple as an improperly torqued pinion nut (been there, done that).

[Drifter22]

Well I don't know Mr. Johnson. I thought I did it right. What kind of experience did you have with this problem?

[53k]

Well I don't know Mr. Johnson. I thought I did it right. What kind of experience did you have with this problem?

If you thought you did it right, you more than likely did. In my case I had my '64 Avanti in a Studebaker shop in preparation for our chapter Route 66 trip in 2003 for a bunch of work that I couldn't do. One thing was changing the rear end from a 3.73 (automatic) to a 3.07. The guy who knew how to do it ran on the pinion nut with an air socket. I had left the car there for six months, but true to form, it wasn't finished until the last minute (and it wasn't really finished). I picked up the car Friday night, drove 120 miles home in the rain with the speedometer not working and the rear end howling. I worked on some of the problems Saturday then we left Sunday morning to begin the trip (lots of problems, but too long a story for here). Anyhow, our first night was in Huntington, WV where a bunch of local Studebaker people were to meet us. Having told them about the noisy rear, they had arranged for me to take to car to a small garage across the line in Kentucky where a 78-year-old man had agreed to look at it. After pulling the differential cover and not seeing anything wrong, he decided to check the pinion nut and found that it was barely tightened. Tightening it properly solved the problem. Upon quizzing the guy who left it loose he admitted that he used the wrong air socket. His other one was set for the proper torque.

[Dan Timberlake]

Google - "popular science say smokey whine " and a page of links shows up.

His January 1970 comment is the one I recall. " 99 times out of 100 once a ring an pinion run wrong for several miles you can not reset and remove the cause of the noise."

I unknowingly ran a Ford Fairmont a few hundred miles on a highway trip with the diff WAY low on oil due to a pinion leak. Suddenly late at night 30 miles from home the slightest acceleration at 75 mph made a noise like a machine gun. bang-bang-bang-bang. Pulled off the highway and talked a pump jockey into putting it up on a lift. The housing was blazing hot, and a dip stick showed essentlally NO lube in the fiff. They had no gear oil (!?) , so we filled it with the thickest motor oil they had. Next day I pulled the rear cover and inspected the teeth. Several or maybe all the ring gear teeth showed a small thin scar (weld?) in the middle of the tooth. About the size of a pencil line maybe 3/8 to 1/2 inch long.
Refilled with GL-whatever it ran for several more years, but had certain speeds it would howl a little.

[JimC]

At some point the rear diff on my lark was run without fluid, which was when the noise appeared. That was maybe 4 years and a couple owners ago. It doesn't seem to have any problems outside the whine. If people are thinking it's not something that will give out on me on the highway, then maybe what I need is to dyna-mat the underside of the car so it won't bug me as much.

[altair]

re differential

Differentials are a very complex mechanical device I would like to offer a couple of opinions. This may require a little effort, but remove the diff cover and with a paint pen mark the ring gear in 4 equal quadrents and number them 1 - 4 then take a piece of paper about .002 and feed the paper through the gears at each marked quadrent turn the paper through and turn it back out again and mark each piece of paper to correspond with the numbers on the ring gear. When you get them all done inspect all the papers. There will be a difference in the crunch pattern, however the paper should only be wrinkled and not cut through if the paper is cut through the clearence is too close. If on all four quadrants the paper is not substantially wrinkled there is too much clearence. When diff gears are made they are machined first and then hardened, the hardening process distorts the ring gear therefore you have to check the gear on all four quardents and adjust it to the closest quadrent. Opinion #2 check the gears to if there is any evidence of pitting ie from rust. Pitting can cause howling, as the oil gets in to the pitt and when the gears mesh the oil is compressed and diesels causing a mini explosion thousands of mini explosions will cause a howling sound. There is no quick easy fix. Option #3 live with the howling. Dave British Columbia

[thunderations]

I've heard stories of "slick" used car dealers that would put cork in the differentials of cars that howled to quiet them down. I don't know how long it worked but if you drank enough wine to get the corks for the whine, you might not even care that it was noisy.

[christophe]

This may require a little effort, but remove the diff cover and with a paint pen mark the ring gear in 4 equal quadrents and number them 1 - 4 then take a piece of paper about .002 and feed the paper through the gears at each marked quadrent turn the paper through and turn it back out again and mark each piece of paper to correspond with the numbers on the ring gear. When you get them all done inspect all the papers. There will be a difference in the crunch pattern, however the paper should only be wrinkled and not cut through if the paper is cut through the clearence is too close. If on all four quadrants the paper is not substantially wrinkled there is too much clearence. When diff gears are made they are machined first and then hardened, the hardening process distorts the ring gear therefore you have to check the gear on all four quardents and adjust it to the closest quadrent.

Thanks Dave.
That's a very neat trick.
I'll check my axle this way.
Then, it occurs to me that we may also use Plastigage there to get accuracy.
Nice day to all.