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I recently changed my differential fluid to a 70-90 synthetic based upon recommendations from this board. I`ll soon be going on a trip to the desert where the temp will be 100+ and was wondering if the high temps will "thin it out" too much or will it be fine ? What about an additive ?
 

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You probably used a 75W-90 gear oil. That is the recommended viscosity for all weather. Please, no additives. All modern lubes do better without any additional products added which upset the balance of the additive package they're made with. The only exception is limited slip additive added to gear oil if you have LSD and the new gear oil it doesn't already have it included.

Ken
 

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DaStray said:
I recently changed my differential fluid to a 70-90 synthetic based upon recommendations from this board. I`ll soon be going on a trip to the desert where the temp will be 100+ and was wondering if the high temps will "thin it out" too much or will it be fine ? What about an additive ?
make sure you use limited slip diff additive almost every tundra has lsd if its 4wd
 

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Re: Re: Differential fluid viscosity

toyotajon said:
make sure you use limited slip diff additive almost every tundra has lsd if its 4wd
Unless you're one of the ones like me who got their Tundra early before it was an option. :( Saving my pennies to get one...think that's my next major mod...
 

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If you used Mobil 1 75W-90 it already has the limited slip additive in the proper ratio, so no need to be concerned.
Also, every tractor/trailer you pass on the highway is running synthetic 75W-90 in its rear end. Including engines with over 500HP, pulling the rocky mountains on a regular basis, going through dessert, etc. One of the many advantages of synthetic oils is their temperature stabilities. i.e. the oil does not thicken with cold NOR does it thin with elevated temperatures. Thus, you have a superior film strength in the 75-90 synthetic over a mineral 85W-140 gear oil at elevated temperatures.
George Morrison, STLE CLS
 

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Beg to Differ

Hi George,
Over the last week the truck got all fluids changed.When I did the rear diff with Mobil1 I had clunk/chatter on turns.
So I added the only LSD additive I could get @ 7:00 pm made by ATP after draining a little Mobil.After all is fine after.
My only concern is when I checked the levels is when loosening the fill plugs I got a sucking vacuum .Is that normal.?
Do I have a breather problem?
Any advice is welome.
Rich R
 

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Yes, you have a clogged breather. Very astute on your part! Probably either clogged or painted over during assembly; not uncommon, however, breather is *very* important for expansion/contraction and cooling.. Very important....
George
 

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2001 Toyota tundra access cab 4.7
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You probably used a 75W-90 gear oil. That is the recommended viscosity for all weather. Please, no additives. All modern lubes do better without any additional products added which upset the balance of the additive package they're made with. The only exception is limited slip additive added to gear oil if you have LSD and the new gear oil it doesn't already have it included.

Ken
Does it have to say Hypoid gear oil or is GL5 ok?I'm having trouble finding the Hypoid gear oil but am finding plenty that says GL5,My owners manual says API GL5 SAE80 HYPOID GEAR OIL,Thx
 
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