Everyone was ok using GL5 in manual trans in usa

[kschachn]

Originally Posted By: MolaKule
Modern GL-5/MT1 lube formulas use what is known as "buffers" or metal deactivators as well as the fact that S-P chemistry contains a special sulfur chemistry that has little reactivity with copper alloys, which is why they have 1A and 1B ratings.

But here is the big question: Why would anyone use a GL-5 rated hypoid differential lube in a car or light truck MT when there is a wide range of dedicated GL-4 rated MTF's specifically formulated for car and light truck transmissions?

I can tell you why I have in the past, it is because my owner's manual says I can use a GL-4 or GL-5 and the stuff I got at the NAPA closest to my house was GL-5. I did tear down the transmission at about 120,000 miles to replace a bad output shaft bearing, and at that time there was no discoloration nor any visible issues with the synchronizers. The bearing failure was somewhat common to this transmission, since then I have not experienced any problems.

Not a reason based in anything other than what the manual said and what was easiest for me at the time.

 

[69GTX]

Originally Posted By: zeng
And this GearBoxVideo guy would have seen more GL5 being dumped into more manual transmissions than all of us combined here, let alone personally viewed various worn and trashed conditions of all internal parts of manual transmissions filled up with GL5 prior.

Hence, his comment on haven't seen bronze/brass synchronizers being damaged/corroded by GL5 would be credible, is it not?


Actually, his commenta mentioned nothing about bronze/brass synchronizers (10-14 min on video) in particular. If this guy does only old style transmissions with only brass/bronze synchronizer rings, then his experiences are probably accurate. Now has he rebuilt dozens or hundreds of Tremecs or similar transmissions with composite carbon fiber/paper lined/scintered metal synchronizers and used GL5 fluids? I suspect not. I'm fairly certain GL5 in my stock 1999 T56 would likely shorten its life considerably, probably by 80% or more. His video gives the impression that ANY manual transmission will do fine on GL5 fluids as he's never seen a lubrication caused failure in any of his rebuilds.

 

[MolaKule]

Originally Posted By: kschachn
Originally Posted By: MolaKule
Modern GL-5/MT1 lube formulas use what is known as "buffers" or metal deactivators as well as the fact that S-P chemistry contains a special sulfur chemistry that has little reactivity with copper alloys, which is why they have 1A and 1B ratings.

But here is the big question: Why would anyone use a GL-5 rated hypoid differential lube in a car or light truck MT when there is a wide range of dedicated GL-4 rated MTF's specifically formulated for car and light truck transmissions?

I can tell you why I have in the past, it is because my owner's manual says I can use a GL-4 or GL-5 and the stuff I got at the NAPA closest to my house was GL-5. I did tear down the transmission at about 120,000 miles to replace a bad output shaft bearing, and at that time there was no discoloration nor any visible issues with the synchronizers. The bearing failure was somewhat common to this transmission, since then I have not experienced any problems.

Not a reason based in anything other than what the manual said and what was easiest for me at the time.



Yes I too used GL-5 back in the early 70's in my Nova's (350 V8) Muncie transmission and got about 75,000 miles out of it until the synchro's wore out, broke and fell into the sump.

But that was because that was about the only MT fluid speced and offered.

Since then we now have dedicated MT oils with much better formulations and the engineers have learned a lot about the interaction between fluids and mechanical's.

 

[Silk]

Before there was GL-4 and GL-5, there was just EP90, and we put it in everything, diffs, gearboxes, steering boxes...anything with gears got EP90. Things wore out, but I don't think there was any problems with brass stuff. Syncro rings got changed as a matter of course on a gearbox rebuild.

 

[zeng]

Originally Posted By: IndyIan
No GL-5 gear oil ever got into my manual transmissions. And they all have to gone to the scrap yard working fine. I'll keep on using GL-4 or what the manufacturer recommends.

Good on you for your pleasant experience with GL4 MTF in manual trans.

But funny thing is there are manual transmissions solely with (recommended) GL4 MTF throughout its life invariably require rebuilds,on occasions, is that not the case in States ?
It is in Malaysia.

Besides there are instances where manual transmission runs into shifting issues with certain GL4 MTF in States , is that not the case there ?
I'm not suggesting you have had shifting issues with GL4 MTF though , for IDK.

 

[zeng]

Sorry, invariably should read as variably.

 

[davison0976]

Looks like early GL-5 blends did have a negative affect on yellow metals/alloys like brass. Then with time manufacturers found a way to negate that. Given some companies have more resources than others, some did it quicker. This created an entire spectrum of GL-5 oils ranging from corrosive to copper to those that are actually less corrosive than GL-4. No wonder there are so many disagreements while both sides have valid points.

Here is a Pentosin video on GL-4 vs GL-5

 

[zeng]

The pdf file from this link of Rand demonstrates API intended GL4 and GL5 gear lubricant ratings to be for applications in both hypoid gears AND manual transmissions.

 

[zeng]

Originally Posted By: Or
I have counted a number of GL-4 lubes from major refiners that have left the market in the last 10 years. What are the new/“resurgence” ones? On his website, I am thinking it is referring to limited boutique oils like from Brad Penn, etc. Which is a poor substitute for the fact used to be able to go into an auto parts store and get them.

I consider it unfathomable for major oil companies having left MTF GL4 market in the past completely , without offering alternatives in its lineup of fluids as replacements, for IDK the US market really.
I'm not suggesting their respective GL5's are the replacements though.
But that's marketing taboo 101 , right?

What Paul claims on youtube dated May 2017 was that :
"There have been more new GL4 oils released in the past 3 years to capture a market."


Isn't this claim plausible ?


Quote:
They seem to be vastly less available now than a few years ago.

Could it be a case of its MTF in GL4 is being replaced with its GL5, as being suitable as MTF in manual transmission ?

Edit:add quotes.