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.