best ATF for transfer case

[Cumsterdump]

quick answer is ATF+4!!!

before coming at me for not searching before posting i did some forum digging before asking as i knew i would be far from the first but the more digging i did the more questions i came across so here i am squashing all the questions.

i’m aware for the np231 that atf+4 is whats called for but ive been hearing viscosity thrown around in forums and how old stuff was best, but old stuff got replaced with new stuff, but the really new stuff is bad for old stuff?!

Long story short what name brand should i look to for this application? because even tho all “will work fine” and i’m aware even the gas station brand is passable id rather take the extra second to get what’s really best for my components so they last as long as possible and so i can learn.

 

[TheBoogieman]

 

[Gilaguy23]

Im curious if anyone has tried 5/20 in the T case. Said to work well. Im going to when i get off my duffer and service the 242 in my ZJ. If it craters..oh well.

 

[jeepguy03]

I've owned various Jeeps with the NP231 and NP242 and serviced several of them for family/friends. I've run ATF+4, Dex/Merc III, and Valvoline Maxlife ATF in them. Each one worked well. The key is keeping the fluid full and clean.

 

[machoheadgames]

It's a transfer case. Any ATF will be fine. It doesn't even have to be ATF. Some run motor oil, some run a light weight gear oil. It really isn't that critical, it just needs some sort of liquid, pumpable lube.

 

[Mr. Bills]

i’m aware for the np231 that atf+4 is whats called for. . . .

Long story short what name brand should i look to for this application?

It doesn't matter what brand.

Every ATF labeled as "ATF+4" meets Chrysler specs.

There is no "premium" ATF+4.

 

[lumberjacklloyd]

Valvoline is probably the top. I run

It's a transfer case. Any ATF will be fine. It doesn't even have to be ATF. Some run motor oil, some run a light weight gear oil. It really isn't that critical, it just needs some sort of liquid, pumpable lube.

The only thing that does matter is viscosity. ANY ATF will work, be careful running motor or gear oils that may be higher than ATF viscosity. The pump is driven off of the output shaft and is not designed for a heavier fluid. This aside, there would be no issue with thicker oils.

 

[mrblaine]

It doesn't matter what brand.

Every ATF labeled as "ATF+4" meets Chrysler specs.

There is no "premium" ATF+4.

One of the few times where "buy any of them, they are all the same", is actually true.

 

[Cumsterdump]

One of the few times where "buy any of them, they are all the same", is actually true.

i assumed they would have detergents or additive packages like engine oil

 

[mrblaine]

i assumed they would have detergents or additive packages like engine oil

The full quote matters. I was reinforcing the fact that all ATF+4 has to meet the Chrysler spec or it can't be called ATF+4 regardless of what brand it is. There is no premium and there is no non premium, there is only ATF+4.

 

[machoheadgames]

The only thing that does matter is viscosity. ANY ATF will work, be careful running motor or gear oils that may be higher than ATF viscosity. The pump is driven off of the output shaft and is not designed for a heavier fluid. This aside, there would be no issue with thicker oils.

The pump is not weak, it can handle the thicker viscosity just fine.

 

[lumberjacklloyd]

The pump is not weak, it can handle the thicker viscosity just fine.

If your pump is supported correctly by the bearing housing...sure.

Put in thick oil with an unsupported pump like so many SYE bearing housings...trouble.

 

[hear]

Agreed that the t-case doesn't actually care that it's even ATF.

As far as ATFs, I've used the walmart brand a TON, but here lately I've used the O'reilly brand because you can get a gallon for like $26. I'll use valvoline if I only need a quart and I've already bought Walmart out their house brand (which happens frequently if I'm working on one).

 

[machoheadgames]

If your pump is supported correctly by the bearing housing...sure.

Put in thick oil with an unsupported pump like so many SYE bearing housings...trouble.

My pump is supported perfectly fine with the stock tail housing and the JB Conversions SYE tailhousing that is installing soon. That's a bad SYE design problem, not a fluid problem. Been there, done that. Rugged Ridge had no support for the pump and it was a problem even with ATF. Two of the tabs broke off of the pump because of the lack of support. Junk.

 

[lumberjacklloyd]

My pump is supported perfectly fine with the stock tail housing and the JB Conversions SYE tailhousing that is installing soon. That's a bad SYE design problem, not a fluid problem. Been there, done that. Rugged Ridge had no support for the pump and it was a problem even with ATF. Two of the tabs broke off of the pump because of the lack of support. Junk.

That's great and I agree. This is an open forum with other vehicles and rigs as well.

 

[mrblaine]

That's great and I agree. This is an open forum with other vehicles and rigs as well.

My apologies for being lost. I thought I was on the Wrangler TJ forum. When did Chris change it?

 

[lumberjacklloyd]

My apologies for being lost. I thought I was on the Wrangler TJ forum. When did Chris change it?

Nothing changed. Just because @machoheadgames is aware of oil pump support and how thicker oils could affect that doesn't mean other people and their associated rigs are.

 

[mrblaine]

Nothing changed. Just because @machoheadgames is aware of oil pump support and how thicker oils could affect that doesn't mean other people and their associated rigs are.

Which TJ transfer cases have that problem?

 

[lumberjacklloyd]

Which TJ transfer cases have that problem?

This whole thread has been about an NP231

 

[jonny jeep]

In the service and owners manuals jeep specified whatever ATF was being used in the auto transmissions used in that particular model year.

Doing that meant owners of autos would only have one fluid in there home and reduced the risk of the wrong fluid being used in the auto transmission.

If you have an auto, use the same fluid that is in your transmission. If you have a manual transmission, ANY ATF is fine.