Transfer Case Oil

[Torkman66]

Lots of threads about this with everything from motor oil to ATF to gear oil. I have a bunch of this oil. Ok to run it in Transfer Case?

 

[Speedrdr]

I’m thinking that ATF would be a mighty thin fluid to run in T/C.

Randy
[T/C to mean transfer case]

 

[Torkman66]

I thought so too, but several folks run it. Manual calls for 50w motor oil. I’ve always run 90 w gear oil in them. But one guru said any oil is fine. I just so happen to have several cases of this stuff.

I also have a bunch of Mobile One 15-50. Hate buying more oil if something I have will work fine.

 

[abrogate932]

I thought so too, but several folks run it. Manual calls for 50w motor oil. I’ve always run 90 w gear oil in them. But one guru said any oil is fine. I just so happen to have several cases of this stuff.

I also have a bunch of Mobile One 15-50. Hate buying more oil if something I have will work fine.

https://www.oreillyauto.com/detail/...or-oil-50w-1-quart/val0/race50?q=sae+50&pos=0

I recently rebuilt my Dana 20 and have been running this with no issues. My local O O O'reillys has it on the shelf.

 

[Gupster88]

 

[JB Fab]

View attachment 937378

NOPE! GL5 rated gear-lubes have sulphur based pressure additives that act on the 'yellow metal' of the thrust washers. the microscopic etching of the thrust washer causes friction (=heat). I have torn down too many D20s that the PO had used gear-lube and spun the thrust washer damaging the case and/or the the idler gear.
It doesn't help that most of us are are putting 2-3X the horsepower/torque and running larger tires than stock. Give your D20 a fighting chance...

NOTE: There is an exception where you have had your idler gear machined to accept bearings (eliminating the thrust washers).

 

[Gupster88]

NOPE! GL5 rated gear-lubes have sulphur based pressure additives that act on the 'yellow metal' of the thrust washers. the microscopic etching of the thrust washer causes friction (=heat). I have torn down too many D20s that the PO had used gear-lube and spun the thrust washer damaging the case and/or the the idler gear.
It doesn't help that most of us are are putting 2-3X the horsepower/torque and running larger tires than stock. Give your D20 a fighting chance...

NOTE: There is an exception where you have had your idler gear machined to accept bearings (eliminating the thrust washers).

Good to know. Thanks for the intel. So what is your best recommendation?

 

[bronco italiano]

Call Driven oils or Swepcolube.com and speak to someone about what you have and your application. Swepco 201 gear oil is ok for the D-20 but as Jon from JB said, most GL-5's will damage it.

 

[bronco italiano]

NOPE! GL5 rated gear-lubes have sulphur based pressure additives that act on the 'yellow metal' of the thrust washers. the microscopic etching of the thrust washer causes friction (=heat). I have torn down too many D20s that the PO had used gear-lube and spun the thrust washer damaging the case and/or the the idler gear.
It doesn't help that most of us are are putting 2-3X the horsepower/torque and running larger tires than stock. Give your D20 a fighting chance...

NOTE: There is an exception where you have had your idler gear machined to accept bearings (eliminating the thrust washers).

Jon, Do you have someone in your area that performs the bearing conversion?

 

[ba123]

I’ve thought about this topic as well and wonder what I should be running.

Both my D20 and 9” rear and Detroit locker have this. Should I dump it?

 

[bronco italiano]

I’ve thought about this topic as well and wonder what I should be running.

Both my D20 and 9” rear and Detroit locker have this. Should I dump it?

call AmsOil, some high quality oils may be safe for the thrust washers.

 

[bronco italiano]

This brand is in my VW bus https://drivenracingoil.com/i-30497...DW030oYphWevuPgrBA0KJHF8907qWSJqpvD4CWi-DOjJq

And this in my T-case/drive axles. https://www.swepcolube.com/wp-conte...e-Gear-Lube_Product-Information_English-2.pdf

 

[serial car restorer]

I always used GL-4 gear oil in manual transmissions and t-cases way back when, and GL-5 in diffs. These days I generally use a synthetic MT oil in transmissions, but will still use GL-4 in the t-case and GL-5 in the diffs.

 

[Broncobowsher]

Ford was strange back in the day. For a given transmission (or transfer case) they would spec out 50wt motor oil. That same transmission used by IH, Jeep, GM, Mopar, or anyone else would get regular gear oil.
To confuse people even more, gear oil has a different viscosity scale from motor oil. 50wt motor oil is the same thickness as 90wt gear oil (there is a range for both and it has a lot of overlap)
To make matters even more confusing, GL5 changed. Old GL5 (like 30+ years ago) was fine for bronze. But something changed and GL5 isn't acceptable for bronze now.

 

[Lawndart]

There is plenty of confusion! I'll add another - I have been running AeroShell W100 (50wt) in mine for nearly 100k miles.
Pop by your local small airport, get a quart or two and possibly make a new friend (or two).

 

[Torkman66]

Could not find any 50w at auto parts store. Could you just run 15w-50w motor oil or synthetic (mobile one)? Seems like motor oil or even synthetic would be fine and having the 15-50 would be good for cold mornings.

 

[Broncobowsher]

There is plenty of confusion! I'll add another - I have been running AeroShell W100 (50wt) in mine for nearly 100k miles.
Pop by your local small airport, get a quart or two and possibly make a new friend (or two).

While stirring the pot, I forgot about something.
Detergent vs non-detergent oils. What is detergent oil? It is oil designed to keep contaminates in suspension. Non-detergent oil lets the contaminates settle out. If you go back to pre-50's it was common to maintain an engine by removing the oil can and scraping the crud off the bottom. Then detergent oil came out and is paired with oil filters. The detergent keeps the contaminates in suspension so they can flow through the oil filter and be removed at that time.

So using motor oil as transmission fluid. The oil back in the day, you could easily find non-detergent straight weight motor oils. That is extremely rare today. That leaves you detergent motor oils. But the transfer case doesn't have a filter. Settling out would be a great option. Settling is sort of a filter. But now you have the contaminates held in suspension because detergent oil is in use.

 

[Lawndart]

While stirring the pot, I forgot about something.
Detergent vs non-detergent oils. What is detergent oil? It is oil designed to keep contaminates in suspension. Non-detergent oil lets the contaminates settle out. If you go back to pre-50's it was common to maintain an engine by removing the oil can and scraping the crud off the bottom. Then detergent oil came out and is paired with oil filters. The detergent keeps the contaminates in suspension so they can flow through the oil filter and be removed at that time.

So using motor oil as transmission fluid. The oil back in the day, you could easily find non-detergent straight weight motor oils. That is extremely rare today. That leaves you detergent motor oils. But the transfer case doesn't have a filter. Settling out would be a great option. Settling is sort of a filter. But now you have the contaminates held in suspension because detergent oil is in use.

Good question.
What to use with engines with a centrifuge oil cleaner?
I have access to Aeroshell. It has worked fine for me and drains nearly as clean as it goes in (in my case, once a year with 8000-10000 miles accumulated).

 

[nvrstuk]

I thought so too, but several folks run it. Manual calls for 50w motor oil. I’ve always run 90 w gear oil in them. But one guru said any oil is fine. I just so happen to have several cases of this stuff.

I also have a bunch of Mobile One 15-50. Hate buying more oil if something I have will work fine.

I don't need or want a name, but a gura that says "any oil is fine", means you need to find a new "guru"... Difference between ATF and 50W oil is literally night and day and still trying to be politically correct, just because people use it doesn't lend ANY credibility to the belief that it's the correct stuff to use.

Just saying, don't use it. Spend 20 dollars and use the 50wt. Sell the 15w-50 to your neighbor and use the ATF for starting the bonfire out back. My oil shelves look like a parts store I have so many types of oils that I bought and quit using as I learned that they can't be interchanged.

Here's the article by East Coast Gear Supply that I saved years ago and if you talk with the dozen rear end shops that I talked to they ALL say "Never" use synthetics in 4wd/truck/old car applications. Rice burner might be different but we aren't discussing them.

Shock loading and shear is important. What nobody seems to address is the "clinginess" of dino gear lube. A D20 and a rear end ring gear needs the oil to "climb" the gear to lube the brgs and provide shock/shear protection.

chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://eastcoastgearsupply.com/files/PDF Files/ecgs-gear-oil-recommendation1.pdf?srsltid=AfmBOopG5uRsHA9VSmxBJjMyE2qhGDjxdgK2Asq5xNZ-4JEjcVIslZvu

 

[Torkman66]

Yep, lots of opinions for sure. Liked the article. Thanks. @nvrstuk what brand do you recommend? The Valvoline VR1 listed prior is assessable locally. Thoughts?