GL4 and GL5 gear lube and bronze gears and bushings

[banpkr]

I have been looking for 140 wt. oil safe for bronze gears, found it today at O'Reilly Auto Parts. Straight 140 wt., GL-2,3, and 4 rating. Sold by the gallon.

 

[buickanddeere]

GL-4 is yellow metal safe. So is most motor oils. In fact many diesel motor oils carry a GL-4 and occasionally a GL-5 rating . Of course motor oil is yellow metal safe.
Still some people think a tractor transmission which used to use GL-1 when new. Is going to fail when using "motor oil"?

 

[Soundguy]

You can also find gear oils showing an MT1 rating when looking for yellow metal safe oils.

 

[bx25jim]

I know this may sound crazy to you, But I have a troy bilt horse 2 made in the late 70's from what I can find on it. Just rebuilt it from the ground up after finding it in a barn in pieces. I have been running Mercury Quicksilver High performance gear oil in it for the past 3 or 4 years with no problems at all. I do check it to see if it has changed color (its a nice looking dark green when new) and so far again, no problems. Here are a few pictures of it when I got it verses what it looks like now.....
These are before.....

These are after a rebuild....

 

[tomd999]

Hiya,

OK, I'm a little late to this thread but GL ratings don't address yellow metal corrosion, they are gear lube ratings. The spec you want to look at for yellow metal safe is "Copper Strip Corrosion ASTM D130 rating". Class 1 ratings, either a or b are considered yellow metal safe. It's not until you get into class 3 and 4 that actual corrosion takes place.

www.ptplab.net/upfile/201402/19/154823776.pdf

 

[Soundguy]

Hiya,

OK, I'm a little late to this thread but GL ratings don't address yellow metal corrosion,

Indirectly they do. previous to gl5, it wasn't much of a problem. However after a decade now, different formulations have come and gone.. and it's not much of a problem again. MT1 rated oil.. etc.

 

[RickB]

Indirectly they do. previous to gl5, it wasn't much of a problem. However after a decade now, different formulations have come and gone.. and it's not much of a problem again. MT1 rated oil.. etc.

I disagree. GL-5 oils can be yellow metal safe or not. One can't condemn a GL-5 oil based on that rating, nor can one rely on it being safe for these uses.

 

[tomd999]

I disagree. GL-5 oils can be yellow metal safe or not. One can't condemn a GL-5 oil based on that rating, nor can one rely on it being safe for these uses.

Hiya,

I would say this statement is closer to the truth as API does not mention anything about yellow metal in the GL-4, GL-5 or MT-1 ratings in it white paper for these ratings. I take out of the paper is that both the GL ratings "might" be safe, however, it specifically states that MT-1 is not recommended for synchronized transmissions, makes me wonder if that is because of friction modifiers or a high D130 classification. Basically, the higher the sulfur content of the EP package, the more aggressive the lube will be to copper based metals. (This is the reason the fuel gauge in all the early Dodge Diesels doesn't work, before ULSD, the sender in the tank would corrode and fail)

http://www.api.org/~/media/files/certification/engine-oil-diesel/publications/1560-eighth-edition-april-2013.pdf

Tom

 

[Soundguy]

I disagree. GL-5 oils can be yellow metal safe or not. One can't condemn a GL-5 oil based on that rating, nor can one rely on it being safe for these uses.

No, we agree, maybee I just wasn't clear. I'm saying you can have gl5 that is safe, IF its rated for yellow metals. Many are, many aren't.

Hard for me to get a clear thought laid out on the phone sometimes.

I think TOH has a chart made up on the other board talking about the different ratings and ep addatives. We need to get him to post it again, its been a while since I have seen it.

 

[Soundguy]

Remember, mt1 rated oil gets a score of 1B on the copper corrosion test.

Possible scores are 1-2-3-4, A,B,C,D.

1A is inert or no effect. Mt1 gets 1B.