I get my gears 4.88 put in tomorrow and would like to hear what oil everyone runs. I have not a clue myself what to run

 

I wouldn't run anything expensive or special for the first 1000mi. Get the gears installed, flush at 500mi, then flush again at 500mi and fill with some decent gear oil.

Lot of people on here running Mobil 1, Royal Purple and Lucas.

 

Just use a GL-5 rated fluid in...what is it...80w-90? Whatever is spec'd in the manual. If you change often, there's no reason to run anything exotic unless you tow then use the appropriate weight, which is only available in synthetic.

 

Amsoil when your ready to fill it for the long run.

 

as mentioned, just throw in some basic dino gear oil in during the break in period and after that, whatever you want. a lot of people swear by synth oil but, i have recently started to find that there are some in the industry that will argue that synth won't work as well as dino especially in keeping things cool. just something to consider.

 

I use Mobil 1. I like the fact that it is a synthetic and it doesn’t cost the normal price of other synthetics.

 

I use Mobile 1 as well.

 

Thanks for the input guys. I can't wait to get them put in

 

I change mine every 9k, but i also wheel every chance i get. I prefer el cheapo, that way I can carry three quarts with me in case of emergency, and not spend an extra thirty bucks. Plus, if you change it often, which in my oppinion is a great idea if you frequent mud, or work the diffs hard, the benifits of synthetic are kind of non existent, as you have fresh oil in them at all times anyway.

 

I run Mobil-1, but haven't researched what benefits come from running synthetic in diffs. That said, synthetic is better oil. The running cool issue may make some difference in the diffs, but I have a hard time seeing how a slicker oil could run hotter. In any case, the sythetics are able to handle the heat better.

As said a few times already, the most important thing about oil is that it is clean, free of all impurities, and at the correct level and weight. So with new gears, grab some of the cheapest oil you can find of the correct weight, fill them up right, and drive for 500-1000 miles. After that, then fill with synthetic. Unless as also already mentioned, you are going to be getting contaminants in there all the time - in which case go back to the #1 - clean and free of impurities, so change out more often with cheaper oil.