90 weight oil

[Karl Kostman]

Hey guys I want to change the transmission oil in my 59 730 diesel and the manual says to replace the lubricant with 90 weight transmission fluid, well I know there is no such thing so today I was looking for straight 90 weight oil and I found a lot of 80/90 weight GEAR OIL and 80/140 GEAR OIL but nothing that was labeled 90 weight OIL? Maybe this is a lck of knowledge on my part but Gear oil is NOT the same as oil, or so that is what I have been taught? Am I OK running GEAR LUBE in the transmission? And if so is it ok to run 80/90 GEAR LUBE? Does the lube going into the transmission need to be YELLOW METAL friendly?
Thanks guys and appreciate your thoughts!
Karl

 

[rustred]

remember... 90 wt is old oil and so is the manual and so is the tractor. 80-90 is perfectly fine. and yes you need 80-90 in the transmission also. there is no yellow metal in there. its just an old tractor and 80-90 is the ticket.

 

[buickanddeere]

50 weight motor oil is heavier than 90 weight gear oil . You can also bet that motor oil is yellow metal friendly .
Motor oil does not ruin wet clutch/brakes in case the PTO shaft seal is failing .

 

[Karl Kostman]

I just wanted to thanks you guys for the information I kind of figured 80/90 was going to be OK but always best to make sure! Thanks again!

 

[buickanddeere]

(quoted from post at 18:21:29 09/26/20) I just wanted to thanks you guys for the information I kind of figured 80/90 was going to be OK but always best to make sure! Thanks again!

You are not grasping the concept of gear oil viscosity vs motor oil viscosity .
Why pour SA 90 GL-1 oil into a transmission that will ruin PTO clutches if it leave past the seal ? Vs 50wt motor oil which is GL-4 and yellow metal friendly. And wet clutch/wet brake compatible.

https://www.thelubricantstore.com/understanding-the-viscosity-grade-chart

 

[buickanddeere]

(quoted from post at 18:21:29 09/26/20) I just wanted to thanks you guys for the information I kind of figured 80/90 was going to be OK but always best to make sure! Thanks again!

You are not grasping the concept of gear oil viscosity vs motor oil viscosity .
Why pour SA 90 GL-1 oil into a transmission that will ruin PTO clutches if it leave past the seal ? Vs 50wt motor oil which is GL-4 and yellow metal friendly. And wet clutch/wet brake compatible.

https://www.thelubricantstore.com/understanding-the-viscosity-grade-chart

 

[Karl Kostman]

Buickanddeere you are correct I have a basic understanding of lubricants etc. and the more I learn the more I find out I dont know! Thanks for your suggestion and It does make sense from the clutch wet clutch
standpoint, I like that idea a lot! Will this 50 wt engine oil need to be treated any different than gear oil once its put into the transmission? Will the life of this oil be similar to gear oil? If that
matches up with gear oil than I will proceed in your suggested direction Buickanddeere

Thanks much for your thoughts and they do make sense to me!
Karl

 

[55 50 Ron]

That web site lists 50 weight crankcase as GL-5

 

[buickanddeere]

Motor oil is yellow metal safe.