Ok thanks. It's draining overnight. Tomorrow morning...wait, in a little while, I'll turn it to see if the hidden gear teeth look the same and the visible ones.

 

i had mine changed out and after i had the fluid changed i had this same grinding noise. i asked my mechanic if he added the limited slip additive from dodge and he said no, so i orderd a bottle, added it in there and the noise went away... see if a bottle of that will work if u still have it after u refill with whatever

 

What the heck is gonig on, i thought the AA axles do not need limited slip additive... grinding with Amsoil?? 75/90. i just my case + 4 bottles too, i use Amsoil in everything from kids bikes 4 wheelers, snowmachines cars, boats etc.

This is very troubling news, i wish someone would clear this up for me.

i wonder if the gear noise is just more prevelant with Amsoil? Someone know whats gonig on?

Diese

 

Diese, AAM axles do not need any additive - RTFM. I can't say that Amsoil makes them noisey, because both of mine are quiet - and have been quiet (with and without Amsoil).

If the diffs are noisey, it isn't Amsoil doing it - there's something else going on in there.

 

Heres an update. Since I made the switch over to the Valvoline I haven't noticed any chatter but the big test came today. I had to bring my 10,000lb fiver to the dealer which is about 60 miles away. Like I said above, when towing is when I would notice the chatter the most. Well I am happy to report that I had ZERO chatter. It was smooth as silk as I accelerated from a stop.

My only guess is that Valvoline must add a friction modifier to the Synpower. So whether or not AAM recommends a friction modifier it seems different oils will make a difference in LSD performance.

 

Friction modifier shouldn't make any difference in the AAM. It doesn't have any clutches. Valvoline is API certified so you know you're getting what they say you're getting. Amsoil isn't certified by anyone but their advertising dept. Their warranty puzzles me too. They say you can go up to three times the normal intervals called for by the manufacturer yet their warranty stipulates that you must follow the manufacturers maintenance requirements for Amsoil's warranty to remain valid for whatever it's worth. My owner's manual says I have to use API certified oils in my truck so using Amsoil voids both the manufacturers warranty AND Amsoil's warranty the moment I pour it in. It all just seems too fishy to me. And I've seen absolutely no evidence to suggest that there is any benefit to using any non API approved oils over Valvoline or Mobil 1.

 

My LS rear does the same imediately after changing to the amsoil. I notice it when turning but not usually with the truck empty. Towing and turning is the worst.

 

Can you say "Amsoil Hype"? Most people swear by it, but I've heard lots of complaints about the gear oil and noise after a new install of Amsoil. I did lots of searching and I didn't go with Amsoil in mine because of the complaints.

 

For what its worth - I changed to Redline about 6000 KM ago.. No problems, no noise.

Factory Diff Fluid seemed fine too when I took off the covers & everything looked good (24,000KM).

ZS

 

I have used Amsoil for along time, in alot of different trucks. I just checked the pail of 75w-90 lube I've been using and is says "API MT-1". The limited slip rears that AAM uses are non clutch type units. They are torque sensing units. If you go to their web site they define how they work. As far as Amsoil making the rear end grind.... thats kind of strange. I can tell you my rear has always tried to lock up the rear tires on a 90 degree turn under moderate throttle. However, thats how this limited slip unit works.

 

I notice on 90 degree turns under throttle a 'chatter' but I guess I always thought that was the inside tire breaking loose, which isn't that hard on turns. What do you mean that's how this limited slip works saw boy? I'm not real familiar with their operation.

 

Hannibal ,

your right when you say the AAM's have no clutches. However, the Trac-Rite uses what are called pinion brake shoes. When one wheel starts to spin the pinion pinion gears on that side are forced toward the pinion brake shoes. The pinion brake shoes then cause frictional drag on the opposite pinion gears and side gear. These frictional forces are what transfer the power to the opposite wheel.

So, even though you don't have cluthces you do have frictional media that can chatter and apparently different oils will either cause a chatter or eliminate it.

 

The torque sensing of this unit is always trying to equal out the rear tire speed once the wheels are turning. From a dead stop only 1 tire might spin.... but get both rolling and it will lay a dual patch as long as you want.

 

"I just checked the pail of 75w-90 lube I've been using and is says "API MT-1"

That's pretty clever but it doesn't mean it's API certified. I think it's pretty deceptive when companies do that and even put it in a circular stamp so as to fool the untrained eye.

 

I think you better check the smell and look of the factory synthetic before you report your findings from your sniffolgy of the lube you said above. The new stuff is definately not "brown". You are way wrong.