5w30 oil in transfer case?

[Eric Pylant]

Hey everyone!

I just picked up a 2003 Tahoe LS and am slowly going thru and doing routine maintenance begining with the fluid changes first.

I realize fluids can be very specific for each application but is it so for our transfer cases?

I realize GM recommends Dex III but recently I have been reading about people using 5w30 in these cases.

I replaced my Toyota FJ Cruiser T-case oil and the factory calls for 75w90!! So why do our T-cases require tranny fluid?

Thoughts? Opinions? Facts?

Thanks!
Eric.

 

[Fless]

Different transfer cases spec different fluids due to different technology. My NP246 takes AutoTrakII fluid, and I wouldn't think of putting in anything other than what is spec'd.

What's the make and model of yours?

 

[Eric Pylant]

Different transfer cases spec different fluids due to different technology. My NP246 takes AutoTrakII fluid, and I wouldn't think of putting in anything other than what is spec'd.

What's the make and model of yours?

I believe I have the same T-case

In this video the author sites a editor of Transmission weekly name's Mike Weinberg who recommends using 5w30 in the transfer cases. Seems better than thin tranny fluid. I realize it's recommended from GM to use ATF but would 5w30 hurt anything?

 

[wjburken]

The two fluids are formulated differently. I don’t think 5W-30 has the same anti-foaming characteristics as ATF which may cause issues in the transfer case.

 

[Fless]

I believe I have the same T-case

In this video the author sites a editor of Transmission weekly name's Mike Weinberg who recommends using 5w30 in the transfer cases. Seems better than thin tranny fluid. I realize it's recommended from GM to use ATF but would 5w30 hurt anything?

"Believing" is not knowing; know which T/C you have and use the right fluid. GM does not spec tranny fluid for the NP246. Your T/C may have a tag on it to tell you the make and model.

If you use something else, have at it and report back your results.

 

[afpj]

Post that question on Bob is the oil guy (bitog) forums. I'd like to sit back and watch the responses. Toss in a third option such as cooking oil just for kicks and grins.

 

[Fless]

And it looks like the TC in the video was specifically built to use motor oil. Fine for their warranty, if there is one. Not the case with an OE TC.

 

[exp500]

I guess this is like running 15-40 in a TH-400, some do most don't. Maybe somebody else remembers when Non-detergent oil was considered hydraulic fluid, or even using non-detergent oil for ashless applications. Oils sure have changed over the years, I just wish marketing had to tell the truth. Re- what is synthetic? ALL of it. Never classified by type on the label usually.

 

[Eric Pylant]

Thanks for the replies. I'll dig a little deeper and maybe call some tranny shops who rebuild those T-cases and pick their brain.

I guess I just don't understand what the limiting factor would be in the T-case that would harm it by running 5w30 oil. Would it be too viscus for the oil pump? Maybe it's splash lubricated? Or will it make the TC slip? I'm not sure, but running oil in a T-case doest SEEM that it would cause harm, but maybe.

 

[wjburken]

Thanks for the replies. I'll dig a little deeper and maybe call some tranny shops who rebuild those T-cases and pick their brain.

I guess I just don't understand what the limiting factor would be in the T-case that would harm it by running 5w30 oil. Would it be too viscus for the oil pump? Maybe it's splash lubricated? Or will it make the TC slip? I'm not sure, but running oil in a T-case doest SEEM that it would cause harm, but maybe.

I guess my question is why not run what the manufacturer recommends? What are you hoping to accomplish? I’m not trying to be difficult here or burst your bubble, but if we understood what it is you are trying to achieve, we might be able to better answer your question. Right now, it appears that you read an article where some folks have done it and you think you’re missing out on some sort of utopian experience.

 

[George B]

My .02 but my 03 Suburban used Autotrac II fluid. I would recommend you figure out what case you have and run whats recommended.
Some cases have clutch packs that need the fluid to have a certain penetrating and lubricating property to work correctly.
Even if it's expensive it's not like you change it every 3,000 miles....

 

[Fless]

Thanks for the replies. I'll dig a little deeper and maybe call some tranny shops who rebuild those T-cases and pick their brain.

I guess I just don't understand what the limiting factor would be in the T-case that would harm it by running 5w30 oil. Would it be too viscus for the oil pump? Maybe it's splash lubricated? Or will it make the TC slip? I'm not sure, but running oil in a T-case doest SEEM that it would cause harm, but maybe.

If you do a little reading on wet clutches (which is what your TC probably uses) you'll find out that most of the newer motor oil that's out there will cause them to slip. Think about motorcycles with wet clutches that use the engine's motor oil to lube the clutches, and you'll see special oil with the proper frictional properties. Not the normal auto motor oil.
Here's one article: https://blog.amsoil.com/how-to-protect-a-motorcycle-wet-clutch-and-how-it-works/

 

[Eric Pylant]

It's not that I think 5w30 will add anything that tranny fluid won't, I was only asking to see if anyone knew anything about it.

I ended up following the oem guide. It just sure is interesting that there are so many variations for oil and applications. It makes me wonder if oem recommends a certain type of fluid not only just for protection and wear, but for things like fuel mileage etc.

Like I mentioned, my fj takes 75w oil. Such a far cry from thin tranny fluid; different design I know.

Thanks for all your replies and help!

 

[Eric Pylant]

Good points!

I forgot about dirt bikes and their wet clutches. I believe mine says not to use energy conserving due to the increase for slippage.

 

[ks03]

It makes me wonder if oem recommends a certain type of fluid not only just for protection and wear, but for things like fuel mileage etc.

Fuel economy...pfttt, whatever, right? I’d imagine though, that there is a direct correlation between fuel economy change and heat produced.

 

[79jasper]

Some cases have clutch packs that need the fluid to have a certain penetrating and lubricating property to work correctly.

Ding ding ding.
Now I see no reason to not run a compatible fluid that isn't ATII. But the ATII is readily available, and not that expensive.
I believe valvoline has a compatible fluid. Merchant automotive has one as well.
I prefer ATII since it is a oddball color. If it's leaking, I'll know right away what it is coming from.

Also, I need to do more research on the workings of these cases. I was seeming to understand the clutches only come into play in the auto mode. But i need to do more research.

Sent from my SM-N960U using Tapatalk

 

[Fless]

I think these two articles explain a lot about the NVG246:


https://atracom.blob.core.windows.net/gears/2006/2006-07/2006_07_10.pdf

https://atracom.blob.core.windows.net/gears/2006/2006-08/2006_08_08.pdf

 

[swathdiver]

Hey everyone!

I just picked up a 2003 Tahoe LS and am slowly going thru and doing routine maintenance begining with the fluid changes first.

I realize fluids can be very specific for each application but is it so for our transfer cases?

I realize GM recommends Dex III but recently I have been reading about people using 5w30 in these cases.

I replaced my Toyota FJ Cruiser T-case oil and the factory calls for 75w90!! So why do our T-cases require tranny fluid?

Thoughts? Opinions? Facts?

Thanks!
Eric.

Post up a photo of your transfer case controls on the dash.

 

[Rocket Man]

I run what’s spec’d for everything on my rigs. The last straw was trying to run non-AC Delco fluid in my G80 diff. I read somewhere about guys running Royal Purple 75-90 instead of the AC Delco 75-90 so I had that in for awhile and went down the wormhole about the limited-slip additive and I knew the consensus was lbs additive wasn’t needed or recommended for the G-80 and could cause damage but...I also read that some of the synthetic 75-90’s already had some so I started reading the bottle of RP and right there on the front it said “ With Limited Slip Additive” so I drained it and replaced it. So if it says to use AutoTrac II that’s what it gets. Engine oil is the only non-GM fluid I use. My G-80 diff and NVG149 transfer case have 170k on them with no issues. The rest of the drivetrain I’ve exploded due to supercharger not fluids lol.

 

[Eric Pylant]

Post up a photo of your transfer case controls on the dash.

I'm unable to right now but it has the auto 4x4 option.