Good afternoon all. I have just filled my AA 11.5 differential in the 06 Chevy 2500 with the Gear 300. I was informed by the dealership that the rear has positraction. I also just took note that Motul's site states not to use this in differentials with limited slip. I haven't noticed any ill effects in the 100 miles that I have driven so far. Should I drain it out, or add some LS additive? I was under the impression that synthetic gear oils include a LS additive and it wouldn't be necessary to add some. However, because of Motul's statement, I am a bit concerned. Any advice would be appreciated. Thank you.
Motul Gear 300 75W90 in an AA 11.5 with Posi
- Thread starter e55amgbenz007
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If your AA axle is like the AA rear axle in my '06 Ram, it is an Eaton type gear posi, which works better with NO LS additive. The doofuses that installed my Eaton locker in my F-450 actually put LS additive in it (even though I told them not to), but it hasn't seemed to hurt anything. The gear oil in my Dodge is 75W90 RP Max Gear full synthetic, I ran the same gear oil in my '02 Ram's Dana 80 with no issues either (the RP has the LS additive included, allegedly).
Again, thank you Bullwinkle. I appreciate your insight.
I just found it odd that Motul explicitly stated that the regular Gear 300 is not for use in the limited slip rear ends.
I also have a non-open diff that doesn't require LS additives. Mazda specifically and explicitly told me it doesn't matter whether the gear oil has LS additive. I ran Motorcraft 75W-90 with LS additive for a long time. Now I'm on Motul Gear 300, the non-LS version. No perceptible difference with either oil. Lots of RX-8 owners use fluid with and without LS additives. If it has made a difference for anyone, I haven't seen anyone say so.
I've read that LS additives can accelerate oxidation of the oil. I've also read that that's really the only potential harm in using LS additives in a diff that doesn't need them.
The non-LS version of Gear 300 seems like killer stuff. I haven't seen anything that comes close in terms of VI, and haven't seen a single 75W-90 that matches its cold viscometrics. I almost don't know why anyone would run any other non-LS 75W-90.
I've read that LS additives can accelerate oxidation of the oil. I've also read that that's really the only potential harm in using LS additives in a diff that doesn't need them.
The non-LS version of Gear 300 seems like killer stuff. I haven't seen anything that comes close in terms of VI, and haven't seen a single 75W-90 that matches its cold viscometrics. I almost don't know why anyone would run any other non-LS 75W-90.
Let me start off by saying that I love Gear 300 and it's the only thing I run in Subaru diffs and manuals (my own and any family/friend Subarus I service). For the correct applications, there are very few rivals of the same quality as Gear 300, Amsoil SVG being close in performance but without the same VI.
That being said, do you really think Motul would short themselves all of the potential customers with limited slip rear ends if their engineers did not know something that casual onlookers (mistakenly) think they do??
But, you're out of warranty, and it's your money. Do as you wish, just remember that Motul told you it wasn't the wisest idea.
That being said, do you really think Motul would short themselves all of the potential customers with limited slip rear ends if their engineers did not know something that casual onlookers (mistakenly) think they do??
But, you're out of warranty, and it's your money. Do as you wish, just remember that Motul told you it wasn't the wisest idea.
Left tire on dry pavement.....Right tire in the grass. Floor it. You'll know if it hurt the clutch packs or not.
If Motol says not to use it in posi's. Then I wouldn't.
If Motol says not to use it in posi's. Then I wouldn't.
You have a Eaton Governor Locker that DOES NOT require limited slip additive. You DO NOT have a Posi (Gear or Clutch) in your GM-AAM 11.5" diff unless a aftermarket unit was installed.
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Originally Posted By: clinebarger
You have a Eaton Governor Locker that DOES NOT require limited slip additive. You DO NOT have a Posi (Gear or Clutch) in your GM-AAM 11.5" diff unless a aftermarket unit was installed.
Clinebarger … is it somewhat true that Eaton is flexible working with AAM and other “system” builders that have a host of components sharing the same lubricant bath ….?
Perhaps that’s a reason (good/bad/maybe) that this subject comes back fairly often …
For 20 years I used Mobil 1 in G80’s … and 3 years back switching my G80 to Delvac 1 over the LSD add pack debate …
Just grabbed a gallon of Delvac 1 for the new Tahoe … no worries …
You have a Eaton Governor Locker that DOES NOT require limited slip additive. You DO NOT have a Posi (Gear or Clutch) in your GM-AAM 11.5" diff unless a aftermarket unit was installed.
Clinebarger … is it somewhat true that Eaton is flexible working with AAM and other “system” builders that have a host of components sharing the same lubricant bath ….?
Perhaps that’s a reason (good/bad/maybe) that this subject comes back fairly often …
For 20 years I used Mobil 1 in G80’s … and 3 years back switching my G80 to Delvac 1 over the LSD add pack debate …
Just grabbed a gallon of Delvac 1 for the new Tahoe … no worries …
Thank you clinebarger.
Originally Posted By: 4WD
Originally Posted By: clinebarger
You have a Eaton Governor Locker that DOES NOT require limited slip additive. You DO NOT have a Posi (Gear or Clutch) in your GM-AAM 11.5" diff unless a aftermarket unit was installed.
Clinebarger … is it somewhat true that Eaton is flexible working with AAM and other “system” builders that have a host of components sharing the same lubricant bath ….?
Perhaps that’s a reason (good/bad/maybe) that this subject comes back fairly often …
For 20 years I used Mobil 1 in G80’s … and 3 years back switching my G80 to Delvac 1 over the LSD add pack debate …
Just grabbed a gallon of Delvac 1 for the new Tahoe … no worries …
Of coarse! AAM wants a synthetic 75w90 gear oil for their ring & pinions....Eaton never wanted synthetics used with their traction devices. Something had to give.
LS additive is a secondary issue as it only adversely affects operation with gear biasing differentials like the True-Trac & Torsen.
Some people have noise complaints when using LS gear oil with a Eaton Gov-Lok, I don't & run Mobil 1 LS 75w90 in my 2006 2500HD's AAM 11.5".
G80 just means you have the optional Traction Device installed in your GM vehicle. If you require LS additive is platform/model dependent.
Originally Posted By: clinebarger
You have a Eaton Governor Locker that DOES NOT require limited slip additive. You DO NOT have a Posi (Gear or Clutch) in your GM-AAM 11.5" diff unless a aftermarket unit was installed.
Clinebarger … is it somewhat true that Eaton is flexible working with AAM and other “system” builders that have a host of components sharing the same lubricant bath ….?
Perhaps that’s a reason (good/bad/maybe) that this subject comes back fairly often …
For 20 years I used Mobil 1 in G80’s … and 3 years back switching my G80 to Delvac 1 over the LSD add pack debate …
Just grabbed a gallon of Delvac 1 for the new Tahoe … no worries …
Of coarse! AAM wants a synthetic 75w90 gear oil for their ring & pinions....Eaton never wanted synthetics used with their traction devices. Something had to give.
LS additive is a secondary issue as it only adversely affects operation with gear biasing differentials like the True-Trac & Torsen.
Some people have noise complaints when using LS gear oil with a Eaton Gov-Lok, I don't & run Mobil 1 LS 75w90 in my 2006 2500HD's AAM 11.5".
G80 just means you have the optional Traction Device installed in your GM vehicle. If you require LS additive is platform/model dependent.
Just read a few TSB's from GM and a statement from the original designer/maker at Eaton for the G80. It was stated by both parties to not use LS additives in the G80 rear ends.
I would assume that the parts guy at the dealership was using the term "posi" loosely and without the aforementioned knowledge then when he stated that I have a posi rear.
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