Rear End Growl on Turns

I have a 2002 Sport with what sounds like a cat growling . The whole rear end (ring, pinion, axels, traklock, bearings ect) was replaced at 128k at a dealer. Within 3 months it was binding again and growling on turns. They redid the whole thing again (said they would have their "rear end" guy do it this time). Well it was ok for ~15k miles (out of the Ford 12mo/12k warranty period) and was starting to bind a little but not bad. Now at 195k it is binding and really growling after warming up and you are turning (forward or reverse). I had the fluid changed at one of those oil places about 15k miles ago, but the noise and binding did not go away. They claimed to put the ls additive in. My question is, is it worth changing the fluid myself so I know that it is done right and see if the noise goes away? If I use the Mobil 1 75w-140 full syn with the additive in it already should I still put the 4oz of additive in also? It seems like the ls clutches are binding up (per what my husband says). It only starts after driving a for awhile. No "growling" when cold. How can we verify if it is the clutch packs (they were replaced both times per the invoice from Ford). I assume that to drain you have to remove diff cover? Or is there a drain plug like on the 2002 Explorer with IRS? No towing with vehicle and not abused at all. What if nothing is done? Just will have the growling on turns? It's quiet when driving in straight line. Seems like play in the drive train when stopping/starting. Will have a little "clunk" when removing foot off of brake when starting from a stop unless a very slow easy stop (if that makes sense).

Thanks much!

Zoe

in my experience, a noise on turns has been a bad axle bearing. once it's making noise, changing the fluid will have no effect. it's too late.

It's not a steady growl it's like a pulsing growl. An only on turns. Can bearings go out that fast? If that is what it is it would be the 3rd time in less than 50k miles. Would that also explain the binding and clunking when stopping and starting up after a stop?

Thanks,

Zoe

Sounds to me like its that clutch pack in the rear end again. Obviously the dealer isn't the best place to be taking your truck for that.

You need to find a good driveline speciality shop. Be nice to find one that a few people in the automotive business recommend.

So should I try to change the diff oil to see if the clutches free up some, if that is what it is? If using the Mobil 1 oil with the additive already in, should additional additive still be put in? Or does everything need to be replaced. Again.
You think a Ford dealer would get it right at least one of the times. Does the diff cover have to be removed to drain? What if I just leave if alone?

Thanks much,

Zoe

to me the symptoms sound like a wheel bearing. If the axle shaft was chewed up from a previous bearing failure and not replaced/resleeved/relocated via sav-a-bearing, it won't be long before it fails again...

Bill

Axles, ring and pinion, clutches, wheel bearings were all replaced. Twice now. Would wheel bearings only make the growl kind of sound only on turns? It seems like the the rear end is like a locking one on turns as it seems like the inside wheels on a turn is trying to break loose. If I accelerate fast when turning the inside wheel will chirp sometimes. That's why I am thinking it's the clutch packs not releasing and it's like a locked rear end. Again, do you think it's worth a shot with the fluid change and should the additive still be added even if using the Mobil 1 oil and does the diff cover have to be removed to ensure a complete drain?

Thanks,

Zoe

zoewagner said:

Axles, ring and pinion, clutches, wheel bearings were all replaced. Twice now. Would wheel bearings only make the growl kind of sound only on turns? It seems like the the rear end is like a locking one on turns as it seems like the inside wheels on a turn is trying to break loose. If I accelerate fast when turning the inside wheel will chirp sometimes. That's why I am thinking it's the clutch packs not releasing and it's like a locked rear end. Again, do you think it's worth a shot with the fluid change and should the additive still be added even if using the Mobil 1 oil and does the diff cover have to be removed to ensure a complete drain?

Thanks,

Zoe

Click to expand...

yes, the cover has to be removed to drain the fluid completely. i don't think the ring and pinion are your problem, because there's no noise when driving straight. maybe clutch pack related or an axle bearing. if Mobil 1 gear oil has the additive i don't see why you would need to add more. the additive is a friction modifier which is designed to allow for quiet slippage of the LSD clutch plates.

You need the friction modifier additive if you have limited slip. That's what the owner manual says, trust it.
Mobile 1 is great, but doesn't have the LS additive, because is not needed in other applications (open diff for example).

Heck, I did use it even in my old Sable transmission to cure the TC judder.

Possible a bent axle tube? It will result in premature axle bearing failure. Noisier in turns when you load the bad bearing...

Bill

SoNic67 said:

Mobile 1 is great, but doesn't have the LS additive, because is not needed in other applications (open diff for example).

Click to expand...

Mobil 1 Synthetic Gear Lube 75W-140 LS contains special friction modifiers designed for limited slip-type differentials. In most applications, the addition of special LS (limited slip) additives is not required. For axles requiring the highest level of limited-slip performance, OEM specific LS additives can be added to this fluid.

Click to expand...

http://www.mobiloil.com/USA-English...il_1_Fully_Synthetic_Gear_Lube_75W-140LS.aspx

swshawaii said:

http://www.mobiloil.com/USA-English...il_1_Fully_Synthetic_Gear_Lube_75W-140LS.aspx

Click to expand...

Well:
For axles requiring the highest level of limited-slip performance, OEM specific LS additives can be added to this fluid.

To me that means that, even if it has LS in the name, I will stick to what Ford says and add the $15 additive.
And yes, Mobile 1 is my preferred brand. That's exactly what I have in my LS rear diff too... Mobile1. And same for my oil and oil filter.

Ok. So do you guys think it would be worth trying a fluid change with the Mobil 1 with the additive and add the Ford friction additive? Is there any way to loosen up the clutches without disassembly of the rear end? Right after changing it, is there anything that should be done (like going around in circles both ways, I read that somewhere in here)?

Thanks again,

Zoe

The fluid and additive is really expensive.
I'd get a few quotes (Not the dealer) on having the clutches changed. I think its about a $500.00 job. I had a shop here quote me $800.00 for clutches and gears recently. Can you find a driveline shop? Once I started looking, I found a few. Then after calling a few performance garages, they all recommended one place for me to go to (Not them selves interestingly enough). Maybe you can start making a few phone calls.

The reason I say get a shop with good experience and references in rear end rebuilding is that there are pre-loads that need to be set correctly, or you will end up exactly where you are again in a few thousand miles.

On the additive issue......
I'd do new clutches, fill with synthetic (In your case, mobil 1), and then 'IF' theres chattering in the rear end when turning id add the additive. I'm pretty sure the mobil 1 and amsoil product says that you shouldn't need additive, but that you might.

Its painful that you are having these rear end issues so often.

well, you might want to try putting the additive in (suck out a little fluid first so it will fit). even if the stuff is $20, it might be worth trying before going for a $800+ repair. if the noise stops you know it was just the clutch pack chattering. what i don't understand is that if a clutch pack is worn out, it should be allowing too much slip and not be making noises. i also believe the owners manual states that the synthetic diff fluid should never need to be changed under normal usage.

Koda, I had the same issue as the op.
I was lazy, went to a lube shop for a oil change and they talked me in to doing a dif fluid change with synthetic. They knew I had limited slip, and said they used the correct fluid.
- Well, within 1000 miles I had exactly the issue the OP is having. Off for diagnosis, only to learn my clutches were trashed. Clutches replaced, and correct fluid installed and there has been no issues with that truck since. BTW, its pretty tough to prove a shop used the wrong lube in the diff.

Koda, I agree it doesn't make sense that trashed clutches cause binding, but my experience tells me its clutches, and there is a good chance the wrong fluid was installed. The binding and banging when turning was really bad in my case. Amazing, really.

The additive will have absolutely nothing to do with a growling noise while driving, but will help if you have chattering during turns. Good luck.

Bill

The front axle uses straight 75W-90 with no additives. Orginally the rear was also 75W-90 with friction modifier but was updated to 75W-140 due to axles blowing up. Would not be shocked if someone put in the wrong lube.

I would suggest you simply pick up a tube of friction modifier for $10 and add it to the differential as a start. Either remove the fill plug and drain out enough to add, or pull the ABS sensor and add from the top.

http://www.autozone.com/autozone/ac...l-additive/_/N-259n?itemIdentifier=17352_0_0_

Changing the oil certainly cant hurt anything if you want to go that route. Try the cheaper stuff first in case needs mechanical repair. There is nothing wrong with using 85W-140 which is a standard weight and substantially cheaper (like $25/gallon). It's a little thicker so might reduce gas milage a little but doubt its noticable. Add in some friction modifier and see how things work. If everything quiets down and operates correctly then you know what the problem was. If not, you will be out $50 including the gasket or RTV.

http://www.autozone.com/autozone/pa...-jhegpZa04rs?itemIdentifier=153275_0_0_138522

RomeovilleIL said:

The front axle uses straight 75W-90 with no additives. Orginally the rear was also 75W-90 with friction modifier but was updated to 75W-140 due to axles blowing up. Would not be shocked if someone put in the wrong lube.

I would suggest you simply pick up a tube of friction modifier for $10 and add it to the differential as a start. Either remove the fill plug and drain out enough to add, or pull the ABS sensor and add from the top.

http://www.autozone.com/autozone/ac...l-additive/_/N-259n?itemIdentifier=17352_0_0_

Changing the oil certainly cant hurt anything if you want to go that route. Try the cheaper stuff first in case needs mechanical repair. There is nothing wrong with using 85W-140 which is a standard weight and substantially cheaper (like $25/gallon). It's a little thicker so might reduce gas milage a little but doubt its noticable. Add in some friction modifier and see how things work. If everything quiets down and operates correctly then you know what the problem was. If not, you will be out $50 including the gasket or RTV.

http://www.autozone.com/autozone/pa...-jhegpZa04rs?itemIdentifier=153275_0_0_138522

Click to expand...

i would think that 2 qts of whatever gear oil would be plenty for a diff. save some money and you wont end up with 2 qts of cheap gear oil left over.

Thanks for all the help guys! Ok, I guess my plan is to get the that 7oz additive from Autozone, drain some out of the rear diff (do I need to get some kind of pump?) and add the whole 7oz. Should I get the additive from Ford or is the Autozone stuff ok? The noise is only when turning. It's quiet when going straight.

Thanks again,

Zoe