Topic: Diff Oil 75W90 vs. 80W90?

[Volcom]

Is there any reason to run 75w90 over 80w90 or vis versa?  Can I also run the 75w90 in the t-case and tranny?  I've heard alot of people talking about redline w90 for the tranny but I'm not real concerned about the current G-52 transmission in the truck, I've got a W56 in the garage ready to be put in later.

I don't know much about the different weights of gear oil, so any info on the subject would be great 

[WHITE_TRASH]

Run whats in front of you as long as its GL-5 rated your fine for the most part.

[Volcom [OP]]

Run whats in front of you as long as its GL-5 rated your fine for the most part.

For everything?  Diff's, t-case, and tranny?

[WHITE_TRASH]

yup.  I just buy it in 5 gallon buckets at Wallyworld for cheap and fill'em all.

[Volcom [OP]]

yup.  I just buy it in 5 gallon buckets at Wallyworld for cheap and fill'em all.

Thanks WT 

[blackdiamond]

I think I have 75W140 Royal Purple in my rear differential.  Thicker oil at higher temperatures equal better protection...and lower fuel economy.  This is why racing oils are usually 40+ wt and go as high as 80 wt, they want maximum protection at high rpm/stress and don't really care about fuel consumption.  Nothing wrong with 75 or 80W90 in any case.

From what I have read, the Redline transmission oil is better than others because it is claimed that other synthetic oils are actually too slick for the syncros to work properly.  RL claimes to be the "perfect" oil for things to work well.  Never used it, but sounds reasonable.

[anomaly]

I think I have 75W140 Royal Purple in my rear differential. Thicker oil at higher temperatures equal better protection...and lower fuel economy. This is why racing oils are usually 40+ wt and go as high as 80 wt, they want maximum protection at high rpm/stress and don't really care about fuel consumption. Nothing wrong with 75 or 80W90 in any case.

From what I have read, the Redline transmission oil is better than others because it is claimed that other synthetic oils are actually too slick for the syncros to work properly. RL claimes to be the "perfect" oil for things to work well. Never used it, but sounds reasonable.

RL isn't always the best.  DSMs for example are very picky. Some work best with RL, some with GM Syncromesh (my favorite) etc.