transfercase fluid

Dirtautoguy · August 9, 2015

I'm pretty sure that I have the NP241 transfer case in my 1996 k1500 with the 4l60e and 350 vortec. I checked the fluid in it the other day and it is low. the fluid that is in it is pink like tranny fluid so Im pretty sure thats what it takes is the dexron 3. however I know that dexron 3 has undergone some name changes and a few things in like 2007. but I have heard that dexron vI isnt good for the transfer case so in a way its a pretty simple question. what fluid do I need to replace it with? is there anything that would be better? I do have a quart of napa ATF fluid that I was going to use to top it off untill I could just change it this week. I would also like to put lucas oil stabilizer or tranny fix but I wanted to make sure that would be ok. it looks like it is leaking at the seals but its not leaking very bad yet.

My last question is is the front driveline always supposed to turn?? because I think mine does.

thanks for the help

Dirtautoguy · August 10, 2015

nevermind it does not stay locked in. I did add the napa premium ATF fluid that is supposed to be good for dexron 3 just to top it off and I still plan on changing it this week

barry G · August 10, 2015

you could put the updated synchromesh as found in the nv3500..

expensive, and not in any instructions that I have found.

I had some left over, saving it for the transfer.

I worked at a quick lube, atf in the newer stuff is not like the gear fluid in a cast iron classic.

Always gets my thoughts.

Edited August 10, 2015 by barry G

nikita · August 22, 2015

Is the transfer case manual lever type or pushbutton? If pushbutton, ATF is not the recommeded lubricant. The factory service manual calls for "Automatic Transfer Case Fluid (GM Part No.12378396)" and does not say "or equivalent". The manual case does specify Dexron III.

The manual specifies GM Goodwrench Synthetic Manual Transmission Fluid, with a GM part number, for the manual transmission, but allows for 75W-90 GL-4 gear oil as an equivalent. So, I would not use it in a modern transfer case, more like the old cast iron ones.

If not a pushbutton tcase, I would use "high mileage" ATF, which has seal conditioner. Do not worry that Dexron III is no longer officially listed on the bottle, its a GM legal department thing. Ford and GM stopped licensing old Dexron/Mercon ATF. The oil companies are now forced to use weasel words on the bottle to let you know its the same stuff. "Universal", "Older Vehicle" or Chevron "MD-3" are what to look for.

My front driveshaft turns free in 2H, but is locked (with some gear tooth play) in 4H, just as I expected. If yours is the pushbutton one, the automatic feature may make it difficult to tell when it should turn free or not.

Edited August 25, 2015 by nikita

Dirtautoguy · October 3, 2015

holy crap bat man!! I thought I answered this. maybe it just didnt post I cant remember. I changed the case fluid and did the 2 seals I could get too. It is just a regular shift lever on the floor. and I used ATF in it nothing special. although looking back high mileage woul have been a good idea.

another quick question. my dad has a GMC with the push button 4wd and sometimes it takes a minute for it to go into 4h. is that normal? I have heard that the hydrostatic ones take a minute but I thought his being a 98 it wouldnt have this. thanks!!

GmJunkie · May 25, 2022

Couldn't say for sure but I've heard the GMT-400, obs, whatever you want to call them had issues with the 4wd actuator foinf out, if you aren't careful itll get stuck in 4h or 4l