Synthetic blend rear diff fluid?

[00Silverado4x4]

So the truck has needed a rear diff fluid change for a while. 90k miles and never been done, yup probably overdue. Anyway, went to all usual parts store places & the ONLY fluid around was 75w-90 synthetic blend? So I went with it, job went almost too easy.

Bolts came right out (presoaked with penetrating oil).

Gasket remains came right off, new gasket scraper finally had a job.

Minimal mess (personal first).

Reassembly was done in first shot.

 

Took it around the block a few times, no noise or leaks. Took it for a cruise around town with the family. Still no noises or leaks. So I just concerned if this blend will be ok with the rear end/G80 or am soon to be breaking something? Don't want to "test" the G80 for a few more miles until everything has "broke in" the new fluid. Just hope I didn't mess up using this blend. What do you all think?

[07silver4x4]

what brand did you get? I used Mobil 1 75-90 synthetic and runs smooth. It did not leak while driving in town, but after a rough mountain road ride and a 100 mile trip back home, noticed a little leak. tourqued the bolts and now it's dry.

[00Silverado4x4]

Well I ended up getting Walmart Super Tech brand. After comparing labels looked to be the exact same stuff. I've used the engine oil in the past on other vehicles with no problems so I figured I'd give their gear oil a chance. I also got the front diff to do yet. Got the 80w-90 conventional for that though.

[txab]

No need to use different weights for front and rear. Just use the same. 75w-90 will more than fine. Your new fluid doesn't need to "break in"

[dlstewart01]

This is the problem I have with Walmart Supertech and Warren oil who makes it.

 

http://www.imakenews.com/lng/e_article001335088.cfm?x=bf54LFJ,bd1Rfpn,w