06 Tundra rear diff, Amsoil SVG 75W-90, 44K miles

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I think people are starting to realize why I almost always recommend 75W-110 in SAE 90 applications - I mean for nothing more than any application calling for SAE 90 is very likely old revision SAE J306, and by using NEW 75W-90, they are only using the lower viscosity end of the 90 range, so to speak. By using 75W-110, then you have a 100° fluid in the 18.5-24 cSt range, but still have decent cold weather performance.
 
Originally Posted By: MolaKule
It wasn't clear when you added fresh oil.

So at or after 10.3k, 14.7k, 28.6k, 36.8k, and at 43.9k, you added a fresh charge of SVG 75W90?



No, that is not correct.

The oil was changed, and new oil used, at 15.4, 30.1, 58.8, 95.5, and 139.4K miles. The sample was drawn immediately before the oil was drained to change it.

So Mola - you also do not believe the extra silicon caused added wear?
 
Silicon in the form of dust and dirt can definitely contribute to additional wear, and if is dust and dirt, you need to find the source. If this differential has a breather tube or hose, then that may be the problem.

Another source is contamination may be from the garage or accidentally dropping some dirt into the diffy. I assume you are not using any RTV on the threads when you replace the drain and fill plugs.

As Pablo and I both stated, a SAE 75W110 gives you many advantages.
 
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Si/Mo/Fe uptick from lead foot youngster at the wheel.

I would use the fill as a 5k rinse and upgrade to 75w110, or physically abuse the youngen.

Moly... from iron alloy
Si...ditto

http://www.straighttalkconnectedlife.com/m/car-connection.php
The link is an additive that drastically increases mpg and reduces wear.
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Originally Posted By: Pablo
I think people are starting to realize why I almost always recommend 75W-110 in SAE 90 applications - I mean for nothing more than any application calling for SAE 90 is very likely old revision SAE J306, and by using NEW 75W-90, they are only using the lower viscosity end of the 90 range, so to speak. By using 75W-110, then you have a 100° fluid in the 18.5-24 cSt range, but still have decent cold weather performance.
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Originally Posted By: Pablo
I think people are starting to realize why I almost always recommend 75W-110 in SAE 90 applications - I mean for nothing more than any application calling for SAE 90 is very likely old revision SAE J306, and by using NEW 75W-90, they are only using the lower viscosity end of the 90 range, so to speak. By using 75W-110, then you have a 100° fluid in the 18.5-24 cSt range, but still have decent cold weather performance.


+1

To add further 'confusion' here :-
a)AGMA Gear Lubes Grade 5EP / ISO 220 has viscosity range of KV@40C at 198 - 242 cSt;(i.e above SAE 90)
b)AGMA Gear Lubes Grade 4EP / ISO 150 has viscosity range of KV@40C at 135 - 165 cSt;(i.e above 75W-110)
c)AGMA Gear Lubes Grade 3EP / ISO 100 has viscosity range of KV@40C at 90 - 110 cSt;(i.e above 75W-90)
d)AGMA Gear Lubes Grade 2EP / ISO 68 has viscosity range of KV@40C at 61.2 - 74.8 cSt(i.e above 75W-85)

Correct me if i'm wrong.
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Edit: 80W-90 to SAE90
 
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All: First, below are the pictures I promised of the drain plug after it was removed for the most recent oil change:

Before Wiping: Untouched after removal:


Second Picture: After wiping the residue off (Picture 1 of 2):


Third Picture: After wiping the residue off (Picture 2 of 2):



I went back and consulted the owner's manual just to be sure I was remembering the recommendations correctly. For the Limited Slip Differential, it recommends SAE 90 above 0 degrees F, and below 0 degrees F, SAE 80 or 80W-90.

I think I am going to follow Greasymechtech's, Molacule's, and Pablo's advice: Make the current fill (with Amsoil 75W-90) a very short interval (rinse), drain and refill with 75W-110. What do you all think? Is this a good plan? Should I do another UOA after the short interval?
 
Greasymechtech,

Nothing has been changed in the rear end (other than Brakes (Drums)), and differential oil changes. No issues or noises have ever been present. I have owned this vehicle since new (Well, it had 17 miles on it when it was sitting in the dealer's lot :))
 
Sorry, should clarify. Other than the LS portion, is the non-LS axle identical to the LS diff but gets a 75w140?
I need to check component PN's to see how alike the non-LS is to the LS diff. Open diff--- 75w140, same axle with LS section-- 90 grade. Makes no sense if bearings/ring/pinion... are the same.

Option to maybe skip over the 75w110 and use a 75w140!
 
I do not know about the internal differences between the LS and non-LS differentials - perhaps someone out there might know?
 
Originally Posted By: Greasymechtech
Sorry, should clarify. Other than the LS portion, is the non-LS axle identical to the LS diff but gets a 75w140?
I need to check component PN's to see how alike the non-LS is to the LS diff. Open diff--- 75w140, same axle with LS section-- 90 grade. Makes no sense if bearings/ring/pinion... are the same.

Option to maybe skip over the 75w110 and use a 75w140!



+1

In spite of a potential increase in gear oil temp in single digit with 75W-140 over 75W-110/90/85 (provided it's well below 175F to keep rate of oil oxidation at bay , if one can help it),IMHO the higher operating gear oil viscosity offers substantial and higher level of differential gear tooth wear protection, even at lower range vehicle road speed .

Edit:In this Tundra rear diff, I guess oil temp can be had possibly below 165F.CMIIAW.
 
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Originally Posted By: btanchors

2) No known changes in operation, or service. My 21 year old son drives this vehicle exclusively now. Although he claims he hasn't done anything unusual, he does drive more aggressively than the previous driver represented in earlier UOAs (my wife). He did not tow anything during the interval, nor did he go off-road with it.




Mystery most likely solved. I'm close enough to your sons age that I can tell you the odds are not in your favor. I don't think I knew anybody at 21 who drove their parents vehicles conservatively consistently.
 
Originally Posted By: btanchors
All: First, below are the pictures I promised of the drain plug after it was removed for the most recent oil change:

Before Wiping: Untouched after removal:


Second Picture: After wiping the residue off (Picture 1 of 2):


Third Picture: After wiping the residue off (Picture 2 of 2):



I went back and consulted the owner's manual just to be sure I was remembering the recommendations correctly. For the Limited Slip Differential, it recommends SAE 90 above 0 degrees F, and below 0 degrees F, SAE 80 or 80W-90.

I think I am going to follow Greasymechtech's, Molacule's, and Pablo's advice: Make the current fill (with Amsoil 75W-90) a very short interval (rinse), drain and refill with 75W-110. What do you all think? Is this a good plan? Should I do another UOA after the short interval?


i think it is a good plan. 75w110 is a good all-around viscosity.
 
Originally Posted By: Pablo
I think people are starting to realize why I almost always recommend 75W-110 in SAE 90 applications - I mean for nothing more than any application calling for SAE 90 is very likely old revision SAE J306, and by using NEW 75W-90, they are only using the lower viscosity end of the 90 range, so to speak. By using 75W-110, then you have a 100° fluid in the 18.5-24 cSt range, but still have decent cold weather performance.


Sound advice there.

Wish I'd had it before putting $60 of redline 75W90 in my Nissan.
 
Originally Posted By: Shannow
Originally Posted By: Pablo
I think people are starting to realize why I almost always recommend 75W-110 in SAE 90 applications - I mean for nothing more than any application calling for SAE 90 is very likely old revision SAE J306, and by using NEW 75W-90, they are only using the lower viscosity end of the 90 range, so to speak. By using 75W-110, then you have a 100° fluid in the 18.5-24 cSt range, but still have decent cold weather performance.


Sound advice there.

Wish I'd had it before putting $60 of redline 75W90 in my Nissan.


Operating viscosity of 71.5(SAE90) vs 47.8 cSt(SAE75W90), the choice is obvious to me.
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