GL-1 140wt Gear Oil

M-MAN · Jun 2, 2014

Since this comes up quite a bit and it's very hard to find I thought I'd pass along a good source. It's available from CARQUEST in 5 gallon buckets only. Part# 13617 & priced at $65 in my area.

They have the GL-4 in 140wt as well. It's available in quarts, gallon jug, or 5 gal buckets.

buickanddeere · Jun 2, 2014

don"t know why anybody would bother with GL1 ?
Check the viscosity of Sae gear 90 or 140 to straight weight 50 and 60 motor oil. They are two different scales. 50wt motor oil on par with sae 90 gear.
http://www.bobistheoilguy.com/viscosity-charts/
Straight weight motor oil has high pressure wear additives that GL1 doesn"t. Motor oil is also yellow metal friendly.
Motor oil can be found with a friction material compatible rating. Typically a "Jaso" something rating with no friction modifiers.

Billy NY · Jun 2, 2014

Napa too, Sta-Lube SAE 140W safe for yellow metal, $37/gal. just right for a troy bilt horse transmission in warmer temperatures.

caterpillar guy · Jun 2, 2014

So what is the problem with the GL-5 rating in any of the same wgt of gear oil? I know if you use the GL-1 in a truck rear end you will be replacing the gear unit quite soon.

JDemaris · Jun 2, 2014

One reason is because some tractors that call for GL1 have wet brakes or clutches and motor oil with EP additives or gear oil with EP additives mess up the friction surfaces and plug the linings. I.e. make them too slippery. Especially in Oliver-Cletrac, Terratrac, and Case 310-350 crawlers.

30W or 40W non-detergent motor oil is fine and often the same thing as GL-1 90W gear oil. That assuming the non-detergent oil has no EP or ZDDP additives. Not always easy to know. GL-1 standard for gear oil is obsolete and not longer enforced. I guess the only way you'd know for sure is by buying something called "pure mineral oil" like Tractor Supply sells for N-series Fords.

JDemaris · Jun 2, 2014

GL1 was used in many old truck rears. As I recall, GL5 came out when hypoid gears became common. Many old trucks had spiral-bevel gears or worm-drive rears (like my Ford Model TT).

Mike M · Jun 2, 2014

That's because they bought and read the owners manual you condemned them for not having. LOL !!

M-MAN · Jun 2, 2014

It would be nice if you could find a good motor oil that is heavy enough to replace 140wt. I'm sure it would be better than the old gl1. Problem is no auto parts stores in my area can find anything heavier than straight 40wt motor oil.

Bob · Jun 2, 2014

"you will be replacing the gear unit quite soon"

Gear unit????

GL-1 140wt Gear Oil

M-MAN

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buickanddeere

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Billy NY

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caterpillar guy

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JDemaris

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JDemaris

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Mike M

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M-MAN

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Bob

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