Transfer Case Fluid Question

[WalterMitty]

First some long winded background info before the question.... My transfer case is leaking a little...nothing major, but I am a new MV owner, have close to zero mechanical skills, and it was worrying me a lot. So I read what I could online, and figured out how to check the fluid level, so I wouldn't be driving around with a bone dry case. I parked nearly level, and once the check/fill plug was removed, fluid came running out...so maybe my issue is that it was overfilled. Again, I wasn't 100% flat...so I plan to check again when I can. I do know the transfer case was replaced by the previous owner right before I purchased it, so I know that the fluid is new...it came running out still looking pretty. In any case, here's my question if/when I need to top off the case...which fluid should I use? In looking at the TM/PMs, I read to use Dexron II, and that "Failure to use Dexron II will cause damage...". I've also read that Dexron III is okay to use, as is Dexron VI since it is backward compatible. Also, since I really don't know what is currently in the case, is it okay to "mix" whatever you guys tell me to use, and whatever is in there? After all of this is said maybe I don't have an issue, maybe it just was overfilled, since the leaking seems to have slowed a bit even before I let more out when I was checking the levels.

 

[avlon01]

I just ran into this question also. My GM dealer stated that Dexron III and Dexron II are interchangeable. He also stated that Dexron VI is way more expensive and does not offer any extra benefits.

I topped off my transfer case with III (unknown what was in it) and replaced my transmission fluid with III. S far so good over the last 200 miles.

If you are worried about it, just drain everything and refill. Then you know when it was done and what you used.

Edit: I was confused from a different conversation at the dealer. VI and III are compatible, just VI is much more expensive and does not offer any benefits over III in an older transmission.

 

[Action]

You can't overfill a transfer case unless the humvee is pointing downhill. Any excess will run out the hole before you get the plug back in. The problem can be that the trans fluid running through the cooling loop is leaking into your transfer case.

 

[Retiredwarhorses]

Yea, how much came out? Also, check your trans level...if it's low and the tcase is overflowing, you have a broken cooler loop. To bypass the cooler loop, just use a piece of 3/8 trans hose and loop the cooler back into the 2 nipples, then do the same for the 2 tubes coming form the trans tubes that run over the top of the tcase....you don't actually need this stupid designed cooling loop. But you will toast your trans if you don't correct it.

 

[WalterMitty]

The last I check, the trans fluid level was good, if not maybe a little too full. I think there is just a bad seal at the front of the transfer case...nothing major, but just a little drippy. Only a little streamed out...it always seems like a lot when it surprises you, but it was just a little...so maybe an ounce give or take. I will keep monitoring.

 

[Action]

The previous owner prolly added trans fluid to correct that levelm but ultimately did not fix the cause. The T/C drip you had could have just been too much fluid in it?

 

[BLK HMMWV]

What the **** is Prolly. Please I beg you learn to type the word Probably. Or at least click on the word prolly when the red line appears under it and you will notice it isn't a word . It's a little thing but it's driving me crazy. Now back to the Vampire problem. Sorry BH

 

[darkturbo]

What the **** is Prolly. Please I beg you learn to type the word Probably. Or at least click on the word prolly when the red line appears under it and you will notice it isn't a word . It's a little thing but it's driving me crazy. Now back to the Vampire problem. Sorry BH

hihhii it bother you that much ehh??? can we use "prob." then? I dont really care but spells check is a nice tool that I use often


Now back to the Vampire problem, which is much more interesting.

 

[WalterMitty]

Hey now...who said anything about a vampire problem...don't go there!!! It's just a mildly leaky transfer case front seal....I think. I will check out the air cleaner while I wear a garlic necklace in hopes there's zero trans fluid in there.

 

[Action]

"Vampire " is the phenomenon when your transfer case will suck the fluid from the transmission lines and get overfilled.

 

[WalterMitty]

I'm familiar with the "Vampire" issue, I'm just not sure mine has it. I'm hoping it doesn't. I will be monitoring the fluid levels to see.

 

[Action]

I cant see any other way that the transfer case can have too much fluid in it. I don't believe anyone would be changing fluids on a steep hill.

 

[WalterMitty]

I cant see any other way that the transfer case can have too much fluid in it. I don't believe anyone would be changing fluids on a steep hill.

A few reasons, it might not be the Vampire issue..... I wasn't 100% on flat ground when I checked the levels. The transfer case was recently replaced, so seals might not have been installed properly, and the installer could have overfilled the system (which I think he did). All that being said, I will still be checking trans levels to be sure it's not getting sucked out and running low. I've already read up and took pictures of how to solve the Vampire issue just in case.