Changed out my rear diff fluid yesterday which had amsoil series 2000 75w/90 due to grinding/binding noises that started after replaceing original fluid with the amsoil. After taking the cover off the diif, I found large metal shavings on the magnet of the drain plug and several more inside the pumpkin . I cleaned out the pumpkin and refilled with Mobil 1 75w/90 and imediately the grinding/binding was gone! , really upset at this point and hoping that I didnt ruin the Limited slip/ring and pinion gears.

 

You are not the first person I heard say that about the Amsoil in the rear. Time will tell how your diff will be. Sorry to hear about it.

 

Series 2000 75w-90 is no longer made. It's been replaced with the Severe Duty Gear Oil. I've had the Series 2000 in frt & rear since around 7k miles, now at 27k and haven't had the problems. Because of different posts on this site, I'm starting to lean toward the M1 or Valvoline 75-90w Synthetics.

 

I am another who used amsoil 75w90 and had the noise problems, and switched to mobil 1 75w90 and the problems all went away instantly.

I'd beware 'new' amsoil products unless you know for a fact they are a new formulation. They have a habit of just changing names of their products and calling them new. For example, their old series somethin' 2 stroke racing oil is simply relabeled and called Dominator now..

 

Call Amsoil and report and discuss it with them.Post what they have to say.1-715-392-7101

 

I have been using Royal Purple 75w-90 in my front and rear diff for 12k miles. Everything has been smooth. I will use the same next time I change it.

-Muzzy

 

Red Line 75w-90 installed in the rear for over 15,000 miles now. Will be replacing with new Red Line soon. Rear end is smooth and slient.

 

This seems to be quite a common problem with the anti-spin diffs & Amsoil. Since the gear lube is kind of a pain to change, you might consider just adding a 1/2 4 oz bottle of Amsoil Slip Lock additive (friction modifier). If that doesn't cure it, add another oz, then another. 2 oz should fix it...

 

Friction modifier is not needed for third gen heavy duty rear axles as they do not use clutches.

 

Been running Amsoil for a while now and no problems, no noise. Kind of tough to pin it on the oil when there's been all kinds of thread of folks having loud differentials from the factory.

Then reading about folks saying to add "ounces" of friction modifier to fix it just adds fuel to the folklore and "nonsense".

 

Wll if Amsoil not contacted they might know if there is or is not a problem etc.

 

[QUOTE]Originally posted by bulabula
[B]"Been running Amsoil for a while now and no problems, no noise. Kind of tough to pin it on the oil when there's been all kinds of thread of folks having loud differentials from the factory".
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Well then how do u explain the noise instantly dissapearing as soon as I changed my fluid? And yes I did have a noisy diff from the factory and did have my ring and pinion gear swapped and had no noise/binding until amsoil went in. I believe that Amsoil is reputable and has proven itself fairly well in other applications but not in my rear differential. The amsoil was the direct cause of my noise/binding. So far two days since I changed my fluid to Mobil 1 and no noises or grinding/binding, nock on wood and hope for the best. I will try to contact Amsoil and ask them, but I read that someone already has and they said " we've never heard of this happening and it should'nt ", but I will tell them so they at least have it in there records.

 

There are apparently "brake shoes" in the gear biasing TracRite GT ltd slip diff. There are now quite a few posts about this problem. The manual says friction modifier is not needed, but it looks like some is needed with the regular Amsoil gear lubes. There are some posts that indicate M1 and other syth lubes have some amount of modifier already included, but that would need to be verified by the mfg as it is not confirmed.

Based on all input on other posts, I'll be using M1 in my new '05, which just arrived!

 

How many quarts is your front diff taking?

 

I'll retract my earlier post, think I've just noticed that binding noise from the rear end, from a stop, making left turn too, at almost 27k on truck. Have had the Amsoil Series 2000 75w-90 in frt & rear since 7k miles.
Found out they don't make the Series 2000 anymore, now SEVERE GEAR LUBE.
Since I was ordering the MTL for the 6spd (5 quarts), I just went ahead an ordered the regular synthetic Redline Gear lube 75w-90 (has friction modifier) for Frt&rear too( 8 qts total). Don't think I can go wrong at $7.00 a quart.

BTW 6 spd is 9.5 pts or 5 quarts
Rear end is up to 8pts and frt 5 pts for 8 qts total (depends on which ones you have)
Transfer case is up to 5 pts or 3 quarts (depends on which one you have)