75W140 and my Toyota Sienna

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I am getting ready to change the differential and transfer case fluid in my AWD Sienna. Service manual calls for GL-5 75W-85, so I am sure that the Mobil-1 75W90 GL-5 gear oil will be just dandy. Here is my question, though. I have a spare quart of Mobil-1 75W140 left over from my truck days. My guess is that it would be too heavy for my Sienna gear train, even if mixed 50/50 with 75W90. Thought I would ask the experts though. Thanks.
 
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I've done the same with my Sienna, 50/50 mix. Make sure your rear diff breather isn't clogged, i sprayed mine with fluid film.
No difference in MPG with the heavier mix.
 
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Since the winter rating is the same, it will be fine. It will have a thicker viscosity when warmer. I would run it :)
 
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i run that M1 in everything, Chevy truck, yamaha SxS diffs, Kawasaki C14 gear drive with 46k... It wont hurt anything ans under heavy load will hold up.
 

Oldwolf

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I've done the same with my Sienna, 50/50 mix. Make sure your rear diff breather isn't clogged, i sprayed mine with fluid film.
No difference in MPG with the heavier mix.
Did you remove the breather for inspection?
 

Oldwolf

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Anyone find the Sienna part #'s for the drain plug crush washers for the diff and xfer case?
 

Oldwolf

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That's very close, it is the rear diff plug. Somewhere I read there was a kit available for the xfer and dif seals.
 
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Since the winter rating is the same, it will be fine. It will have a thicker viscosity when warmer.

Not exactly. It's a popular misconception though. Above freezing the 75W-140 is commonly thicker
both cold and hot compared to 75W-90. If in doubt I'd suggest you just compare some PIs and VOAs.
At 40°C/104°F a 75W-140 often ~50 % thicker, so that's no less than at 100°C where it's also roughly
50 % thicker as a 75W-90 in many if not most cases. It's very much the same when comparing a GL-4
75W-80 with a GL-4 75-90 btw., and the difference is probably still considerable near freezing point.

Still ok using it though, especially if diluted w/ 75W-90. However I'd still use 75W-90 GL-5 only, since
there's no gain going even thicker, just the added drag and some imponderabilities as you're mixing
two (hopefully not too) different oils.
.
 

4WD

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Not exactly. It's a popular misconception though. Above freezing the 75W-140 is commonly thicker
both cold and hot compared to 75W-90. If in doubt I'd suggest you just compare some PIs and VOAs.
At 40°C/104°F a 75W-140 often ~50 % thicker, so that's no less than at 100°C where it's also roughly
50 % thicker as a 75W-90 in many if not most cases. It's very much the same when comparing a GL-4
75W-80 with a GL-4 75-90 btw., and the difference is probably still considerable near freezing point.

Still ok using it though, especially if diluted w/ 75W-90. However I'd still use 75W-90 GL-5 only, since
there's no gain going even thicker, just the added drag and some imponderabilities as you're mixing
two (hopefully not too) different oils.
.
Sure - we even see some of that in 0W20 vs 0W40 …
I have 85W140 dino in the Rubicon - and even in Texas will drop the rear to 80W90 semi for winter … that’s basically “sling flow” to the pinion bearing …
 
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