What type of gear oil??

[kewlgye]

I need to change my gear oil in my front and rear diffs. on my '98 k1500. A GM tech told me 75w90 synthetic for the front, I figured the same for the rear, but I'm not sure. Any info is appreciated. Also, my front is pretty bad, so I'd like to flush it with something, if anyone has any suggestions as to what to flush it with, throw them out there. Thanks.

[facn8me]

75w 90 is what i run in both front and rear. Royal purple synthetic is my weapon of choice. I would recomend synth but is not nessacary.

[fossil]

Check owners manual and use recomended oil. No surprises that way.

[Jacqson]

75w 90 is what i run in both front and rear. Royal purple synthetic is my weapon of choice. I would recomend synth but is not nessacary.

 

<{POST_SNAPBACK}>

 

 

 

I'm running 75W-90 in both my axles with E-lockers except my weapon of choice is Amsoil Severe Gear. I would also recommend synthetic as well. IMHO, much better wear protection. Amsoil, Royal Purple, Redline are just some of the names of good synthetics.

[Butch 02 Denali]

LOL. I was going to comment that the factory recommends GL5 Synthetic for the rear if it has a G80, but then I noticed that the original post was made Feb 1, 2005!!!!

 

Hopefully he's changed his oil by now!!!!

 

But, I've used engine oil to flush diffs. Drain, fill with any old engine oil, then drive up and down the driveway a few times with very light throttle. (you don't want to put a load on the gears) Drain, and refill with the gear oil of choice.

[Jacqson]

LOL. I was going to comment that the factory recommends GL5 Synthetic for the rear if it has a G80, but then I noticed that the original post was made Feb 1, 2005!!!!

 

Hopefully he's changed his oil by now!!!!

 

But, I've used engine oil to flush diffs. Drain, fill with any old engine oil, then drive up and down the driveway a few times with very light throttle. (you don't want to put a load on the gears) Drain, and refill with the gear oil of choice.

 

<{POST_SNAPBACK}>

 

 

 

I hear yah. After I posted I noticed the original posting date as well.