I'm going to change the oil in my transmission (NP435), and through reading countless articles online I've decided to go with 50wt motor oil instead of gear lube. When I went to buy it all I could find was 20w-50 motor oil. Is this going to be the same as regular 50wt?

I read a couple of articles on what the 20w means, but honestly I'm having trouble grasping what in the world it means. So is putting 20w-50 in the tranny going to be the same as putting SAE 50 in there?

 

Gear oil is what you want in your tranny.



John

 

50wt oil is what is listed for this tranny, so that's what I'm wanting to use. Even if 80/90 gear lube is around the same viscosity. I guess it's just me being stubborn . Again, I'm wondering if the 20w50 is going to work the same as straight 50w, being as I can't seem to grasp the whole 20w thing.

 

I don't know what kind of transmission you have, but on my 63 f100 i used gear oil for the differentials, transmission and transfer case. I haven't driven it a whole lot, but it works better than it did before.

 

You don't want high detergent motor oil in you gear box. Buy hey it's your truck and if you want to be stubborn, go ahead and play like Burger King and have it your way.





John

 

PM,
I understand you'd like to follow the manufacturer's recommendations.
But stop and realize that your manual was written decades ago!
Just like many things, lubricants have made massive improvements over the years.

For most folks, a readily-available, quality name-brand, manual transmission gear lube is fine. I tell my friends I stay away from the expensive, synthetic oils and lubes - and I use the saved $$ for other things.

Here is a well-worded article on the subject of motor oil vs. gear lube:
Gear Lube and Gear Oil Ratings Basic Functions and Requirements
Although this article is putting some spin on the benefits of AMSOIL, I think the article is factually good.

In my vehicles, I use a quality petro-based 75W-140 gear lube in my '60s/'70s-designed manual transmissions and differentials; nothing fancy.
I schedule a lube change every 3-4 years, depending on the amount of usage. Because I know these boxes are vented to the air, thus are capable of getting moisture inside and loosing some of the ingredients via the cycles of lube heating & cooling. For my 4X4 Jeep, I change the gear lubes every Spring. I figure it's cheap insurance considering the cost of repairing / replacing gearboxes.

SOAPBOX TIME:
Whenever I partake in conversations regarding which lube to use, I really don't care if you use this brand or that brand, petroleum-based or synthetic-based. I just must stress that the largest KILLER of engines, transmissions, differentials, transfer cases, steering box or other gearboxes isn't WHAT BRAND or WEIGHT of lube you put in it --- rather that the lube is IN THERE at all!

The #1 reason so many engines & gearboxes die a terrible death is due to being operated without the correct AMOUNT of lube. So the moral is: ALWAYS keep an eye out for any such leaks/drips; if any are detected, repair them. Lastly, check & maintain the lube level.

Even if I don't suspect a leak or drip, I like to check the level of lube in my vehicle gearboxes at least every 6 months to ensure the lube level is still maintained.
Praise the Lord, Amen......

BarnieTrk

P.S.
Here is some more good info on types of gear lube: http://www.finalube.com/reference_ma...Categories.htm

 

Straight 50 is available. Most auto parts stores will order it for you. Regular 80W-90 gear oil works fine in The NP435 unless you have a very cold climate. Then it will make for some slow shifts.

50W is non sulfarized/non detergent engine oil. It should have no detergents.-jowilker?
20W-50 is a 20W oil that has 50W proprities due to rising heat, unwinding polymers in it.
20W-50 is not a substitute for 50W in gear usage.

 

Thank you flipklos for finally answering what I had originally asked. The difference between 20w-50 and 50 wt. I will go ahead and have the auto store order me some straight 50wt oil for the tranny.