GL-1 Transmission SAE 90 Oil

[KalamazooJohnny]

I went to 6 places looking for GL-1 Oil to fill my manual transmission. The only place that had it is Tractor Supply and it says its for old Ford tractors. Thats what I got, but just wondering if anyone else has used this particular transmission fluid and how it works? They only had it in a gallon bottle. It was about $20.

[rlux4]

The weight is 90, and the rating is GL1, no matter where it's sold. The GL1 rating is pure oil without any additives, as the number goes up it indicates that different additives are in it, that's why FIAT recommends GL1, some of the additives in the other ratings are hard on the "yellow" metals in the tranny: brass. There are other lubes you can use, but GL1 is what FIAT recommended. But that was a long time ago and lubrication technology has advanced, hence some guys do use a more modern lube. I got GL1 with my rebuilt tranny from Jon Logan, and that's what I use, but I've seen the inside of Alvons' tranny after a lot of miles using Valvoline racing oil and it was slick as a whistle, and shifted smooter too.
Ron

[Exit98]

My NAPA store down the street got it for me in a day.

[KalamazooJohnny]

Just got done changing that transmission oil out. I am wondering if it has ever been done before.
I am sickened by the amount of metal shavings and chips I removed from the magnetic plug. No wonder
she rattles so. I guess I will be needing that extra transmission in the garage eventually after all.

[wikkid]

Metal shavings are normal, but keep an eye on it.

I also ended up with Tractor Supply GL-1 oil; Napa could have supplied it on special order, though. I don't know enough about modern oils and additives and all that to know what else might be good to use.

[rlux4]

It's been discussed ad nauseum. Several people have done a lot of research to help us know what is good or not good for our trannys. A search on the subject would bring up a lot of information.
Ron