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Gl1, gl4 and gl5 gear oils

Posted: Mon Aug 06, 2018 7:56 pm
by audiocontr
So I've been reading what I don't understand... basically the issue of yellow metal safe gear oil. Folks are scaring me with gl5 talk, and gl4 is tough to find.

Is the gl5 autozone and coastal gear oil safe for our trucks, or do I need to move to something like: https://www.napaonline.com/en/p/FCA65205

Re: Gl1, gl4 and gl5 gear oils

Posted: Mon Aug 06, 2018 9:40 pm
by edzz
Transmissions must be GL4 not GL4/GL5. GL5 rated will eat the yellow metal synchros. And yes all the parts stores will tell you wrong. You will most likely not find it on the shelf and have to order it.

Amsoil is a good source for GL4.

Was surprised when I found out my 2001 Nissan Xterra 5 speed trans requires GL4. I would have thought it was recent enough to use GL4 / GL5 however thats a big no, no. Don't ask how i learned this, damn previous owner... :>>

Re: Gl1, gl4 and gl5 gear oils

Posted: Mon Aug 06, 2018 11:05 pm
by VinceAtReal4x4s
You can use GL5 oils from Royal Purple and Redline which are Gl4 safe oils. RP also makes a "Synchromax" oil designed for manual transmissions that normally call for multi weight oils and ATF. I got into all of this some time back, which included phone calls with the chemical engineers at Royal Purple, Mobil, Redline, etc.

I currently run Royal Purple MAX GEAR 75W90 in my diffs and transfer and will switch to the Synchromax for my trans. next time but Im running fairly new Redline ATF for now.

I'd seriously consider a high-end synthetic like RP for gears because, why not spend a few more dollars for your rare, expensive parts? You will notice better shifting and cold operation too, and it lowers operating temps overall. RP is also easy to get in the US and why I switched (or am switching) over to it recently from Redline. It's not cheap but... "Pay for the good stuff and you only cry once".

As has been discussed here before, a lot of people leave dino oil in the hubs due to leaking syn oil ruining brakes beyond being able to clean them off, as you can do with dino oil, although if I had done a hub rebuild with all new seals, I think the hubs would really benefit from a heavier syn oil like the RP 75-140w.

Amazon is a good oil source these days.

Re: Gl1, gl4 and gl5 gear oils

Posted: Tue Aug 07, 2018 11:40 am
by rmel
Vince, curious, why the switch from Redline to Royal Purple?

I do plan on giving one or the other a try in my TD Tranie, It's always been temperamental shifting up from 1'st to 2'nd.

Incidentally, both these companies are now under "new management". The small guys just don't have a chance at survival.
Could be a good thing or a bad thing, but in both cases each were acquired by large blenders in the business with lots of
resources.

Redline --> Acquired by Dominus Capital in 2013 (holding company, typically not good) --> Sold to Phillips 66 2014 (not necessarily bad).
http://investor.phillips66.com/financia ... fault.aspx

Royal Purple --> acquired by Calumet Specialty Products Partners, L.P. 2012 (big blender with on shore refineries, could be good).
https://en.wikipedia.org/wiki/Calumet_S ... s_Partners

Re: Gl1, gl4 and gl5 gear oils

Posted: Fri Aug 10, 2018 9:46 am
by rmel
Done, 6 quarts of Royal Purple on it's way. Been thinking about
going Synthetic for the next change out and to see if shifting
would be a tad smoother. I'll let you all know, I should get this
in the this weekend and some runs up in the neighborhood Sunday.

Eeezzzz, it's expensive, cheaper than a Tranie overhaul though :wink:

ron

Re: Gl1, gl4 and gl5 gear oils

Posted: Fri Aug 10, 2018 6:17 pm
by 4x4Pinz
Never a problem getting the stores to bring in Sta-lube GL4. I only use it in transmission so don't need a bunch. I keep a gallon on hand and just reorder as needed. Sta-lube is carried by almost all auto parts stores. The folks I have seen her that have made the synthetic switch have spent some good money and time replacing seals, just not worth it to have to do that much work for the little benefit. Might be different if a complete rebuild was done.

Re: Gl1, gl4 and gl5 gear oils

Posted: Fri Aug 10, 2018 7:50 pm
by rmel
Well, the only real seal issue one might have with Synthetic oil versus dino oil
is that dino oil is very long chain molecules that can aid in "plugging up weak
seals versus short chain for synthetic. Short chains could find sneaky paths through
weak seals, thus leaks. Other than that a good synthetic will not harm seals that
are good, whether they are paper, rubber of synthetic rubber.

That said sta-lube is good stuff! I might go with that in the X-case if I can find
it locally. But this weekend the tranie is getting Purple in it's bilge. I'll let you
know if that made a difference in shifting or just made my wallet thinner.

Re: Gl1, gl4 and gl5 gear oils

Posted: Fri Aug 10, 2018 9:16 pm
by VinceAtReal4x4s
Never once have I had a high-end syn. gear lube cause a leak... and Ive changed out a few. The benefits far out-weigh the chance you need new seals and if you do, then you do.

Re: Gl1, gl4 and gl5 gear oils

Posted: Sun Aug 12, 2018 4:07 am
by montieth
Shell has the Omala line of gear oils that are yellow metal safe. I've bough 5 gallon pails of it for my ferret and dingo.

Re: Gl1, gl4 and gl5 gear oils

Posted: Mon Sep 10, 2018 5:18 pm
by Jake2015
Ron,

What were you results with RP in your trannie? Good, bad, or no effect?

Re: Gl1, gl4 and gl5 gear oils

Posted: Mon Sep 10, 2018 5:31 pm
by rmel
Certainly my finicky 2'nd gear synco is no worse, possibly shifting slightly smoother.
For sure there is now less worry about any possible reaction to Yellow metal. Though I
was using a high end Gear lub from Lucas -- claimed to be GL4 friendly but not clear
what they really meant. In any case I'm sticking with Royal Purple from now on in the
Tranie and X-case. I'll stay with Lucas in the diff's and Portals.

Re: Gl1, gl4 and gl5 gear oils

Posted: Wed Sep 12, 2018 12:16 am
by Jake2015
Ron, which Royal Purple did you use?

Re: Gl1, gl4 and gl5 gear oils

Posted: Wed Sep 12, 2018 9:36 am
by rmel