Oil & Fuel Which Oil to use in the transmission?? Nortrac 254

[nt254]

I have a Nortrac 254. I am confused as to which oil to use in the transmission. A few people I have talked to and the tractor manual say to use 30wt oil. However others say to use gear oil 80w/90 or similar. How do I know which to use (Is 30wt oil too thin or is 80w/90 gear oil too thick??) I do have some noise in the transmission when the creaper gear is in high range. Any help would be very appreciated.
Thanks,
Nt254

[RonMar]

It is a GEAR box, it should have GEAR oil in it. Gear oil is engineered to be a little more "sticky" so it adheres to the gear teeth a little better and maintains a better film between the gear teeth as they mesh and unmesh while rotating under load. Since this is not a precision large surface area fit such as is found in a rod or crank bearing, and this is not a pressure lubricated application, you want the oil to be a little more sticky to protect the gear teeth faces. If you are any place remotely warm, 30Wt will thin out pretty well also and provide less protection.

Because of the composition of the bearings used, you want a gear oil that is "yellow metal friendly". Because they are straight cut gears, you also want an oil that has "low foam" or "anti foam" properties. I think most all makes of GL-4 oil are yellow metal compatible, but I had a hard time finding GL-4 when I had to look last. GL-5 is more common, but most don't mention anything about yellow metal compatibility, so read the label carefully.

[Bob Rooks]

Some common sense does apply here, and RonMar is correct. Typically, a universal 80w-90 gear lubricant will have a viscosity index of ~95, whereas a universal series-3 30w motor oil will have a viscosity index of ~104. The gear lubricants are formulated with non-foaming and extreme pressure (EP) additives not found in motor oils. A good quality gear lubricant is formulated from paraffinic base stocks, will meet the API service categories of GL-5 and MT-1, and will be indicated for all straight cut, spiral bevel, and hypoid gear sets, and ball, taper roller, and plain bearings.

[biggerten]

A few months ago I changed the transmission/differential oil on my Jinma 354, a bigger brother of your Nortarc (rebadged Jinma). After extensive research, I settled on Coastal 80W90, $40 for a 5 gallon pail at Autozone. This meets GL-5 and MT-1 specs, the MT-1 spec is indicative of the "yellow metal friendly" aspect.

If you live where it's warmer, you may want a higher weight.

[Diamondpilot]

Use the 80W90. I have a 254 and use the same Coastal stuff and it quited it down quite a bit. My tractor is pushing 500 hours and zero tranny or front axle problems. I changed it at 50 hours then again at 350 hours.

I use the same 80W90 in my gear boxes on my post hole digger, finish mower, bush hog, ect. I buy it in a 5 gallon pail and got a hand pump for it from TSC the fits on top of the bucket and has a dispensing hose.



Chris

[3RRL]

A side question to the "yellow metal" safe gear oils...
Has anybody determined if there is indeed and "yellow metals" in our gear boxes, transmission or differentials? I've had a peek inside the trans and also had the front drive units completely apart on my Kama, and don't recall seeing any "yellow metals". Looked like lots of roller bearings fut no bronze bushings that I can recall. Maybe someone can verify this? I'm saying if there aren't any, then yellow metal safe might not really be an issue for us?
Wouldn't that be nice to know?

[greg_g]

Has anybody determined if there is indeed and "yellow metals" in our gear boxes, transmission or differentials?

Yup. Chip Uren among others. Regardless, there must be plenty of machines out there that still do. Otherwise I don't think the oil companies would waste any time on Making their GL5 oils MT1 compliant. So I err on the side of caution, since I don't see any meaningful price difference between GL5 and GL5+MT1 rated gear oil

/./greg//

[nt254]

Hello,
Thanks for the great responses. So everyone agrees that 80w/90 gear oil is Not too thick for the transmission. Given time to get through the bearings, etc. Will the gear oil be able to get to the creaper box? I assume that it would be good to use for the front axle as well?
Thanks for all the information.
NT254

[greg_g]

Hello,
Thanks for the great responses. So everyone agrees that 80w/90 gear oil is Not too thick for the transmission. Given time to get through the bearings, etc. Will the gear oil be able to get to the creaper box? I assume that it would be good to use for the front axle as well?
Thanks for all the information.
NT254

The viscosity of 80W90 is roughly the equivalent of 20W50 engine oil (see chart). Not too thick at all for gear boxes. In fact - during the heat of July/August where I'm at - I find it too thin. I've migrated to 85W140.

There is an oil passage forward from the tranny case, but many owners don't trust it. They take off the creeper cover and make sure the level is correct. Some have gone as far as to drill and tap for a separate dipstick.

And whatever you elect to use for the creeper/tranny/rear diff - use that in the front diff too.

//greg//

[biggerten]

..... then yellow metal safe might not really be an issue for us?
Wouldn't that be nice to know?

It would be nice to know. But I don't know. Soooo..... I erred on the side of caution, since it doesn't hurt to have the MT-1 rating.

I just don't trust that since one owner doesn't have any, that the next one is the same, I've seen too many differences from one tractor to the next.

If I ever have to tear into mine, then I'll know.