Quote:
Originally Posted by whunter
I disagree with the negative assumption.
From my experience, most owners are wise enough to open and clean the differential when the old fluid comes out with sediment.
Often this is discovered and cleaned while changing the older clip style axles.
On vehicles new to me, I usually replace the differential mount and open the differential for cleaning at the earliest moment.
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I do have to apologize to the OP for the negativity of my post. I didn't mean to make this situation a worst case scenario.
In the quotes above is what I have been trying to convey.
Quote:
Originally Posted by martureo
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Are you suggesting that convential oil OR running synthetic with an additional change is better than just switching to synthetic outright? ..... I'm pretty sure 90% of that "crap" is removed when the diff cover is removed and the diff is wiped clean. I do tend to agree that if it's just a drain and fill that plenty of debris will remain and another change (synthetic or conventional) will need to be done shortly.
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Absolutely when you are not opening up the cover to clean it out. I would agree that 90% of the debris can be removed by a wipe down. I would also consider another drain and refill after a couple hundred for peace of mind, but probably not necessary.
Quote:
Originally Posted by martureo
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I'd like to know what type of "crap" you're talking about.
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I've seen all kinds of debris. Metal shavings, dirt/grime/sediment, thickened fluid that leaves a grimy dark coating all over, burnt fluid, flakes of god knows what, water and etc.
Quote:
Originally Posted by martureo
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Back to my TD. I'm planning on putting 75w90 LubroMoly in it. Since it's not that expensive or that inconvenient, would it benefit the discussion if I filled it with something different? Would another change of the oil in say 1,000 miles show anything in your opinion?
I'm pretty sure changing the oil with the cover removed to wipe out debris will be more beneficial than the choice of replacement oil. But I'm kinda curious as to what difference synthetic oils will make.
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As far as using something other than Liqui Moly or Lubro Moly 75w90? Yeah sure, try something else out.
I'm actually interested in this Service Bulletin Roy brings up in giving the OK to use 75w90. The original MB recommendation is to use 80w90. Food for thought....If you look at the MSDS of these fluids you will find the viscosity (cST) at 40°C between the two weights are significant. For instance
Castrol Axle LS and
Fuchs 80w90 has a cST of 140
Lubro Moly 75w90 has a cST of 82
Mobil 1 75w 90 has a cST of 103
So what does these numbers tell us? Lubro moly 75w90 is 59% the viscosity of the castrol and Fuchs 80w90. And Mobil 1 75w90 is 75% the viscosity of 80w90. Although I've had no problems, it would seem 75w90 might be too thin.