Transfer case oil

I only recently got my hmmwv, and while doing fluids and such across the board I found my transfer case quite low on fluid. I used what we had on hand at work. It’s called MD3. It’s an ATF meant for older vehicles calling for Dex 2/3 and the older Merc.
Should this be ok or should I source something labelled Dex 3 on the front? Personally I think it’s fine, but some guys know more hmmwv quirks then I do,

thank you ,

You should drain and replace ALL the fluids and filters, you have no idea how old any of the fluids are or even if any of the fluids are correct.
EDIT, this is CHEAP insurance that EVERY new owner should do as soon as they get their HMMWV, UNLESS it was just serviced by a credible experienced shop like RWH for example

Mogman said:

You should drain and replace ALL the fluids and filters, you have no idea how old any of the fluids are or even if any of the fluids are correct.
EDIT, this is CHEAP insurance EVERY new owner should do as soon as they get their HMMWV

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yes, I’m in process of doing this. I didn’t trust anything.
Have to do trans filter and fluid and wheel ends when my spindle locking hardware arrives.

But the question remains, is the Dex2/3 equivkianr fluid ok?

I would say if it is listed as a DEX3 equivalent, short term you will be OK, any oil is better than no oil!!

Still no reason not to change it tomorrow, not waiting on anything for that job, you have at least checked all the fluid levels including the hubs yes?

Trans and filter is being done this weekend. That fluid is correct level and very clean. I’ve been a diesel tech for 20 years, so all I’ve been doing is catching up on the maintenance before I start using the truck.

To be honest, every fluid except the coolant was clean and looked/smelled correct. Coolant was last checked by the army in 2017 and it was nasty, I changed all the rubber hoses and flushed every component.

Hub oil levels are ok, but will be changed soon regardless. Waiting on my washers.

When you say short term, is there a better fluid to run in the T case? It’s an NP218 if that matters, I did read NOT to use Dex VI. This stuff was all I had that was dex3 equivalent and needed to go
Home. I live 1.5miles from my work which is great.

I think most run DEX3 equivalent in the T case, some run DEX VI

Mogman said:

I think most run DEX3 equivalent in the T case, some run DEX VI

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Ok thanks. I guess if it’s no good I’ll find out eventually haha.

It’s solid advice though, change everything, that was my outlook. Even the last owner, I know he did nothing and even if he did, I wanted my own baseline of dates, mileages, what I used etc,
Same with spindle bearing hardware. Just replace it. Why wonder or worry?

I know the info is widely available but it might make a good sticky at the forum top.

Did not mean to pound on you, it just shocks me how many folks get a HMMWV especially out of DRMO and if it runs they just start driving it, then later wonder why they are having so many issues.
POST some pics!!
MM

Mogman said:

Did not mean to pound on you, it just shocks me how many folks get a HMMWV especially out of DRMO and if it runs they just start driving it, then later wonder why they are having so many issues.
POST some pics!!
MM

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No worries , it’s good advice. The the guy I got it from just drove it. But he only had it on the road for about 100 miles til I bought it. I disassembled all the carpets and such and shop vac all the junk out. Spray lubed a lot of stuff. It’s not an exotic truck but it’s mine.

I used ACDelco GM Original Equipment 10-4033 75W-90 Manual Transmission and Transfer Case Fluid in my transfer case

The pubs for mine said DexVI, so it got Dex VI.

Transmission fluid is usually a 10w with additives.
Gear oil is much thicker......
That is a big difference in oil!

juanprado said:

Transmission fluid is usually a 10w with additives.
Gear oil is much thicker......
That is a big difference in oil!

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Yes from 80w90 in the diff to Dex vi in the trans it’s a wide difference.

Hummer Guy said:

I used ACDelco GM Original Equipment 10-4033 75W-90 Manual Transmission and Transfer Case Fluid in my transfer case

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That is for cast iron transmissions/transfer cases not the aluminum ones

Mogman said:

That is for cast iron transmissions/transfer cases not the aluminum ones

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I was thinking of switching to that Delco manual
Trans/tcase one, should I ? Or as mine is aluminum just leave my dex3 equivalent ?

CanadianAR said:

I was thinking of switching to that Delco manual
Trans/tcase one, should I ? Or as mine is aluminum just leave my dex3 equivalent ?

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I would use what the TMs call for, depending on the publish date that would be DEX III or DEX VI, I personally use DEX III

Mogman said:

I would use what the TMs call for, depending on the publish date that would be DEX III or DEX VI, I personally use DEX III

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i guess my concern is that, GM no longer licenses Dexron 3, so everything is technically an equivalent.
I guess at that point I just need to trust the brand I choose,

Dexron III in the Us is widely available. It is what I would recommend to use. Transfer case failures are not a widespread military problem and I would use what is OE and has millions of miles of use. If in Canada it is not available then the later Dexron should work. The difference is in the additives for the friction materials and valve internal components which really don't come to play in the transfer case in this application.

Some of the later models have a rear differential cooler looped into the transfer case using ATF and I doubt gear oil could be pushed backed there and return efficiently. Some models were coolant cooled.

juanprado said:

Dexron III in the Us is widely available. It is what I would recommend to use. Transfer case failures are not a widespread military problem and I would use what is OE and has millions of miles of use. If in Canada it is not available then the later Dexron should work. The difference is in the additives for the friction materials and valve internal components which really don't come to play in the transfer case in this application.

Some of the later models have a rear differential cooler looped into the transfer case using ATF and I doubt gear oil could be pushed backed there and return efficiently. Some models were coolant cooled.

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AR is correct, there is only DEX III equivalent available now, I would stay away from the "all vehicle" BLAH BLAH fluids.