Gl4 Or Gl5 For Differentials

I’m sure this has been discussed numerous times so I apologize in advance for another thread. I’ve read through several of them and still don’t know whether I should use GL4 or GL5 gear oil in the diffs. I was initially going to buy the Sta-Lube 85W90 GL4 from Amazon but now I’m not so sure. Is that safe in my diffs? It must be better than the sludge that dripped out yesterday..

For reference, the rig is a 67 CJ5 with the V6, D27 front and D44 rear.

Thanks!
MP

 

Since there is not any yellow metals in the differentials, you can run GL5. Its the transmission/transfer case you have to use GL4.

 

I don't think there is a problem to use GL-4 throughout.

 

GL-5 is generally cheaper than the Sta Lube GL4. I keep both on hand and use the cheaper when I can

 

Thanks, all!

 

You can buy GL-5 in a gallon bottle at Walmart for less than half the price of GL-4 on Amazon. It's what I use in axles.

 

Perfect, thank you for the insight.