Gl-4

[dsfloyd]

I can't find this gear oil any where. Everything is GL-5. I know the GL-4 is needed for the gear box because of corrosion. Does anyone know where I can get it? I am holding out hope that NAPA will cary some. Is the transfer case and everything else fine with the GL-5?

[zed]

napa sells a generic gl-4 in a gallon? bottle.

royal purple and lucas make non corrosive gear oils as well but they aren't labled gl-4 they just "meet gl-5" well they're all backwards compatible.. cept for the corrosives in gl-5.. which is strange.. arent there still yellow metals (brass bronze) in t-5s and some non carbon t-56s..

the GL-4 is only important because it can slightly corrode yellow metals (your syncros and maybe bushings).. SO.. something labeled "non corrosive" or gl-4 gl-3 will do

It looks like gl-5 will be fine in the transfer case/overdrive. I don't see any brass parts at a glance.

Its not super corrosive.. but it may be why mine has failed at 126k
THen again.. they're junk transmissions in series trucks.

[polar]

Amsoil https://www.amsoil.com/storefront/svg.aspx
makes a GL-4 specific Gear Lube.

Also Redline MTL is a GL-4.

[zed]

My feelings on the redline and especially amsoil products...
Your lubricants should never out-value your vehicle..
It lasted 30-60 years on plain dinosaurs.. now-a-days.. even the non synthetics are chock full o additives making them totally different than they were 10 years ago... those premium race oils are good products.. but overkill.

the napa oil isnt 20 bucks a gallon

[dsfloyd]

Thanks but I'd have to agree with Zed. I will possibly run some synthetics in my other vehicles (required in my trucks rearend), but definately sticking to cheap dino oil for the series.

[zed]

oh yes.. I do run synths in all my close tolerance high pressure newer vehicles they ask for it if not require it.... Don't get me wrong I love synthetic oils. But the rover doesn't need it or want it. Till I build a funny-car.. i'm not using lucas or redline.