M1 75w90 2000 Rear Diff 100k

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cheetahdriver

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my next 4 posts will be prime examples of how smart (ok, never been SUCCESSFULLY accused) people can do stupid things. when i bought the Tundra in 2000, i had all of the oils shifted to syn at 3k. then i went along thinking i had it whupped until 100k, got busy and let things go to 120k. while i probably didn't do much damage, i went way over what i should have. the rear diff here is the TRD limited slip, i had installed at 20k.

Code:


OIL M1 75w90

MILES IN USE 100k

MILES 124k

SAMPLE TAKEN



ALUMINUM 8

CHROMIUM 4

IRON 763

COPPER 1

LEAD 1

TIN 0

MOLYBDENUM 1

NICKEL 2

MANGANESE 9

SILVER 0

TITANIUM 1

POTASSIUM 3

BORON 128

SILICON 170

SODIUM 29

CALCIUM 27

MAGNESIUM 5

PHOSPHORUS 2212

ZINC 49

BARIUM 1



INSOLUBLES 0.3

WATER 0

FLASHPOINT ºF 395

SUS VIS 210ºF 82.6

cSt @ 212ºF 16.16

TAN 1.6
 
Does your Diff cover have one of those magnets on it? Just wondering. I dont think the numbers on your front diff looked that bad. I have seen posts like this before, thats why i try to do all my gear stuff around 30k Intervals. It may not make a darn bit if difference but it makes me feel better.
 
I run synthetic gear oils 50,000-70,000 miles and dino 30,000. The only gear oil I would actually have the nerve to go 100k with is Amsoil SVG. That is because:

1. I am a big chicken on extended OCI's
2. I know guys who have run SVG 200k so I figure 100k would be ok.
 
Thank you for doing these 4 UOA's, they're great reference points!!
 
Originally Posted By: PT1
I run synthetic gear oils 50,000-70,000 miles and dino 30,000. The only gear oil I would actually have the nerve to go 100k with is Amsoil SVG. That is because:

1. I am a big chicken on extended OCI's
2. I know guys who have run SVG 200k so I figure 100k would be ok.
The M1 worked.
 
I agree with LargeCarManX2. I did the same 100k interval with Mobil 1 75W-90 in my K1500 and it's still kicking with 180k on the odo.

The iron may look a little "shocking" but consider the work this diff has done for 100k. All things considered I think it served you well.
 
is there an accepted "condemn" level on gear oil? i know engine oil it is 150ppm Fe. the 700ppm range Fe did kinda make me sit up and take notice...
 
i don't know that that there are any TRD L/S unit UOAs on the board, i have mixed emotions about the unit.

i think 30k will be my next change on all of these. the Tundra engine is running like a 1M mile unit, would hate to have the running gear wear out first.
 
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Thanks much for this! It's a great snapshot of an average truck with a good oil in it over the long term. I wouldn't sweat this at all. I think both the oil and the truck held up well. The one general condemnation number I got for iron in axles was
By way of mild critique, if you had done a 30K change after the 3K, or done a 5K instead of a 3K, and then left it to now, that iron number would be a lot lower. At 3K, a rear axle still has a lot of breaking in to do and metal to shed. Once broken in, they shed a lot less metal. I don't have exact figures for axles, and I'm sure they may vary from mfr. to mfr., but I have it from several experts that automatic trans break in wear metal levels drop sharply at about 5K.

All said, both the oil and the truck have done well by you!
 
i have to admit, i love this truck. it was mine for the 1st 100k, then i gave it to my wife for a tow vehicle for horses, but i still use it occasionally. last year i jumped in it and drove to california (a ~3700 round trip), doing nothing more than changing the oil in prep (it was at 10k anyway) and changing out the stock radio. not only did it do the trip excellently, it was comfortable the whole way. my wife and i have commented several times that if it got totalled, we would have to go looking for a low mileage 06, as the new tundras just don't interest us much.
 
Either the metallurgy of the diffy is great, or the oil is great, or the combo works very well.

763 PPM/100,000 miles = essentially nil ppm/1k.
 
Originally Posted By: MolaKule
Either the metallurgy of the diffy is great, or the oil is great, or the combo works very well.

763 PPM/100,000 miles = essentially nil ppm/1k.



Mola, do you have any condemnation numbers handy? Some idea of what would be a bad number form a diff that wasn't hurting (not like that one of yours you posted a while back). Just curious. I had something a while back, which I can't find now, that listed 850ppm over 60K miles... at least that's what I recall. I should probably rely less on my memory. Anyway, like you, I thought his numbers were pretty darn good!
 
Here is a UOA I did awhile back with a short run of Valvoline dino 80W90 GL5. It will give you some idea what the wear rate is on a stock (open) diff. Although your diff has LSD and includes your break-in period, I'd say you probably went too long for my liking. But you already know that.

http://www.bobistheoilguy.com/forums/ubb...true#Post862033

I have LE1605 in mine now and will probably sample it after 30K OCI.
 
Regarding condemnation limits.

This is only for Chevy 10 bolt diffys:

I try to run the factory front and rear diffy fluid for a year or less then drain with a UOA, and clean out with rag and solvent.

Then put in a synthetic and then UOA the rear differential fluid at 30k past the replacement point. The front differential fluid is tested every 50k.

My personal condemnation limit for the rear differential is 200PPM of ferrous material at 30k. If it is less than that, I run it another 30k and retest.

For the Nissan differentials, and since cover removal is a pain, I simply drain, UOA, and replace every 20k to 30k to keep an eye on the wear trends and fluid health. Drain and fill plugs on the Nissan PAthFinder and Frontier make it easy.

Without a baseline UOA at the beginning, you can't see if the machining material and break-in coatings got flushed.
 
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