What kind of diff oil does everyone use?

Thor

Thor

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I am going to change my diff oil tomorrow and wanted to see what people are using. I’ve got a Dana 44 with stock 3.73s in the rear and I do some towing with the Jeep. I’ve seen where they recommend 75/140 if you tow and also conventional will help dissipate heat better than synthetic. What’s your thoughts on this and what do you guys use?
 
Conventional here and yes it is known to extract heat out of the gears better than synthetics do. The exact viscosity is not important though higher viscosities are a good idea for towing or more extreme offroad use.
 
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Thor said:
What about front diff? 80/90 seems common practice
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That works fine, the viscosity is not critical. The harder the use the better a higher viscosity is.

When the use of a conventional gear lube becomes especially important is after new gears have been installed. It's less important for factory installed gears.
 
Lucas 85w-140 or Amsoil 75w-140 in both difs, depends on whether i am already online shopping or misplaced another 10mm socket
 
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I have another "what about..." question. I'll be putting a Torq locker in my dana 30 soon. I'm going to use a conventional 85w-140 (Valvoline) that they recommend to reduce the audible clicking sound.

Can that same conventional 85w-140 be used in the Dana 44 in the back with the trac lock clutches without any problems to them? It's neither the 80w-90 or synthetic 75w-140 for towing that the owners manual recommends, but it does have the Limited Slip additive in it already.

I'd like to be able to just have one kind of gear oil on the shelf.
 
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