[ArchangelSerra]

My differential is making a whining noise when i get up to 82mph anything under that its nice and quiet...

anyone have any thoughts on why this is happening...

BTW how hard is it to open up the diff. and check out the gearing then real seal it?

Will i have to replace all the oil? Would i have to torque the bolts?


----Kory

 

[sloopercat]

I bought this stuff in a big green and white plastic toothpaste tube looking container at Autozone. Meant for LSD. Claimed to quiet differential whine. What the heck, it was less than five bucks. So I drained the diff, put a tube of this stuff in and filled the rest with petroleum based diff oil. The whine went away. Might be worth a shot.

That diff is for sale, 100K miles. Located in Atlanta.

When I changed to a 7MGTE, I went with a 3.73 and a new tru-trac diff.

 

[Supra_devil]

i've only heard good things about redline and amsoil, if you get some of their lsd oil that should help too. i've heard thatford has an lsd oil that comes premixed that you could get or order from any dealership.

 

[jimvegas00]

The Ford gear oil does not come pre mixed with the additive. Go to your local ford dealer and ask for a bottle of C9AZ19B542A. It is a friction modifier for use in lsd diffs. It's mainly used to stop lsd clutch chatter and noise when turning. It might reduce straight line noises also but that's not as likely. HTH
Jim (who works at ford)

 

[Angkistrodon]

Arch has a good question.....My 85 LSD does the same thing between 70 and 80 mph. It would be nice just to change the lube and thats it.....but ......I can't just let it go like that!! Is a certian bearing that has gone bad?????????

 

[Angkistrodon]

ALSO the whine only happens when gas is applied, at coast its fine.

 

[ArchangelSerra]

ALSO the whine only happens when gas is applied, at coast its fine.

OMG THATS THE SAME THING THATS HAPPENING NOW! AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!

NOW IM REALLY WORRIED ABOUT MY BABY....

 

[ArchangelSerra]

I bought this stuff in a big green and white plastic toothpaste tube looking container at Autozone. Meant for LSD. Claimed to quiet differential whine. What the heck, it was less than five bucks. So I drained the diff, put a tube of this stuff in and filled the rest with petroleum based diff oil. The whine went away. Might be worth a shot.

That diff is for sale, 100K miles. Located in Atlanta.

When I changed to a 7MGTE, I went with a 3.73 and a new tru-trac diff.

Any idea what this magical mystery lube is? (Yes im mocking the Beatles' Magical Mystery Tour, but its only out of respect)

Green and white plastic toothpaste tube looking thing didn't quite help me when i was at autozone yesterday....

I had the diff reoiled resealed and retorqued and the whine still happens, the dude couldnt really tell me anything other than that he didn't see any metal in the draining diff fluid....

Sigh....


---Kory

 

[sloopercat]

No idea what the stuff was called, I just remember the container. Looks like the type you buy outboard motor lower unit lube in. Same size as those also. They had it in the same area as the other diff lubes.

 

[lechner]

the stuff in the large toothpaste tube is a trans-x additive to change normal diff fluid to lsd fluid. Better to buy lsd fluid in the first place, then add the additive too if you want. DID NOT make my whining noise only when under push (not coast) go away. I think it may be the transmission or U-Joints. I'm having this problem on my automatic though. Was yours a manual with the same whine? Cause if so it probably is the driveshaft not the transmission.

 

[AJ]

Probably made by Sta-Lube CRC. I have a blue and white tube "Equa-Torque tm", "Limited Slip Differential Oil Additive" tube states for equalized wheel traction, prevents chattering, jerking and slipping.

To be used with GL-5 oil per instructions.

 

[sloopercat]

the stuff in the large toothpaste tube is a trans-x additive to change normal diff fluid to lsd fluid. Better to buy lsd fluid in the first place, then add the additive too if you want. DID NOT make my whining noise only when under push (not coast) go away. I think it may be the transmission or U-Joints. I'm having this problem on my automatic though. Was yours a manual with the same whine? Cause if so it probably is the driveshaft not the transmission.

Thanks, it also claimed to quiet gear whine, if that is the stuff. All I know is it worked in mine. May not work for all. The noise from nime was pretty minor to begin with. Maybe a fresh drain and fill was all it needed.

 

[SkoonMA67]

...

Think about what happens when you are on throttle or off throttle...

when you are on the gas the pinion and the crown gear touch each other on one side of the tooth because the engine is turning them.

But, when you are coasting, the rear tires are turning the diff and the gears are riding on the opposite side of the gear tooth (They are called the drive and coast sides, actually =)

In my diff in particular, the side bearings are on their way out... still drivable, but they are dieing... slowly =(

My backlash is also out of spec because of the milleage, so that causes a small bit of howling (and clunking going from on the gas to coasting) too... the gears seem to be taking it all in stride, but the teeth are pollished, which is not good... eventually they will die too...

Therefor, you could have one of two problems:

1) Your side bearings are toast, which is probably the most probable cause... due to milleage

2) Your pinion and crown gear are worn out on the drive side of the tooth, again due to milleage

It could be either or... Id be more suspect of the gears if the diff was clunking when you shift. If it does not clunk, suspect the bearings first but dont rule out the gears... too little backlash can cause howling too!!

Just my 2¢ =)

Aaron

 

[ArchangelSerra]

Re: ...

Think about what happens when you are on throttle or off throttle...

when you are on the gas the pinion and the crown gear touch each other on one side of the tooth because the engine is turning them.

But, when you are coasting, the rear tires are turning the diff and the gears are riding on the opposite side of the gear tooth (They are called the drive and coast sides, actually =)

In my diff in particular, the side bearings are on their way out... still drivable, but they are dieing... slowly =(

My backlash is also out of spec because of the milleage, so that causes a small bit of howling (and clunking going from on the gas to coasting) too... the gears seem to be taking it all in stride, but the teeth are pollished, which is not good... eventually they will die too...

Therefor, you could have one of two problems:

1) Your side bearings are toast, which is probably the most probable cause... due to milleage

2) Your pinion and crown gear are worn out on the drive side of the tooth, again due to milleage

It could be either or... Id be more suspect of the gears if the diff was clunking when you shift. If it does not clunk, suspect the bearings first but dont rule out the gears... too little backlash can cause howling too!!

Just my 2¢ =)

Aaron

sorry i forgot to close this thread... my diff was replaced, its all better now thanks for everyones help on this!

 

[NORCALDREW]

skoon speaks the truth about the backlash, but one thing he forgot to mention....
There are two thrust bearings located on the pinion. As the ngas is applied and let off, the helical cut on the pinion and ring gear force the pinion to "walk" front and back. These bearings hold the pinion in place as well as control the load from a drive to coast condition. If the diff is whining while the gas is applied but tones down when it is let off, your rear pinion bearing is toast. While replacing this bearing, it would be a wise investment to also replace the front pinion bearing. Heck, might as well change the carrier bearings while your at it and depending on the mileage of your car and your driving style, buy a new set of clutchpacks. These start going out around 65k. Good luck in fixing your diff. If your doing this yourself (im sure you already know this) your pinion depth and backlash are imperative to how long your gears and bearings last.

 

[ArchangelSerra]

skoon speaks the truth about the backlash, but one thing he forgot to mention....
There are two thrust bearings located on the pinion. As the ngas is applied and let off, the helical cut on the pinion and ring gear force the pinion to "walk" front and back. These bearings hold the pinion in place as well as control the load from a drive to coast condition. If the diff is whining while the gas is applied but tones down when it is let off, your rear pinion bearing is toast. While replacing this bearing, it would be a wise investment to also replace the front pinion bearing. Heck, might as well change the carrier bearings while your at it and depending on the mileage of your car and your driving style, buy a new set of clutchpacks. These start going out around 65k. Good luck in fixing your diff. If your doing this yourself (im sure you already know this) your pinion depth and backlash are imperative to how long your gears and bearings last.

as i said... this thread is closed, my differential is fixed well, its been replaced, problem solved thanks for everyones help...

 

[NORCALDREW]

Soory, Im a noobie to this posting bit. Just tryin to put in my 2 cents. Glad to hear your rear end is up and tickin now.

 

[lechner]

Sorry to bring this back from dead, but I'm just now getting around to fixing this whining problem. Based on what Norcaldrew wrote, it sounds like it is the rear pinion bearing, but my manual doesn't mention this. I know you can change the pinion oil seal between the driveshaft and diff without removing the diff and you take out the front bearing when doing this. I'm not sure exactly where the rear pinion bearing is. Can you also get at the rear pinion bearing without removing the diff, and if so, how? As always, thanks for any help.
Oh, and as for changing clutchpacks, hate to sound stupid but what/where are those? I don't think my diff is LSD and the car is an auto, so do I have these?

 

[NORCALDREW]

if your car does not have an lsd, it does not have clutchpacks. The clutch packs sit between the differential side gears and the carreir. Your axles slide into them and they are what controls the limited slip action in the differential. When they rub together enough, (ie when turning) the friction causes the clutch discs to bind together....delivering the power from the diff to both wheels. Its kinda tough to comprehend. I think KAZZ's website has a good tutorial on clutch type lsd's. If you dont have an lsd currently, and you are looking to get one....I would recomend tru-track. I beleive they use a worm gear drive instead of clutches. This has a more aggressive lsd action, handles more power and needs less maintenance.

 

[lechner]

If I had more money, I would definitely buy the tru-trac. But I just need to make this one run reliably and the whine worries me. What do you think the odds are replacing the rear pinion bearing will solve the problem and how hard/expensive is this to do? It's been whining for 6 weeks of driving already, will it destroy the diff if I don't fix it right away?