Tranfer case fluid change

[Highbeam]

Well I changed the t/c to mobile 1 last night. I have the nv243 with a push button 4wd and low range non-autotrac. The t/c uses about 2.5 quarts of atf.

Warning: when you remove the bottom plug, 1" diameter, the atf will blow out of there like a red mexican dinner colon shot for about 2 feet of horizontal flight and then land either in your eye or make a huge puddle on the floor directly past your drain pan.

I had my wife ask what was so darn funny because I was laughing at the lame deal and the huge mess.

I pumped in the new fluid with the gear oil pump, used antiseize on the plugs and sealed her up. Good easy project for 15 bucks of mobile 1.

Really though, I made a bigger mess doing this than I did when dropping the tranny pan to change the filter in the transmission.

 

[Jeff Allen]

Highbeam,
Are your looking for added durability with the Mobil 1? Gm has an extreme use t/c fluid available, also helps with engagement noises and such. I don't remember the part number off hand, but I can look it up for you at work. It's dark blue in color and there was a service bulletin recommending it a while back.

 

[Highbeam]

Looking for efficiency and better low temperature engagement. I have the nv243 and the gm blue fluid is for the autotrac t/c from what I understand. I even called the dealer and went through a long process to figure out which fluid was correct and atf was the answer from two different sources, wtf is up with the owner's manual only giving gm part #s for the required fluids. I know the transfer case is pretty simple and may not benefit much from the better lube but since I was doing a b2b fluid change I had no intention of skimping for the standard fluid. It looks like there must be at least a couple t/c bearings that turn in 2wd that are bathed in t/c fluid and if they can spin more freely then it was worth it.

It was quite a colon blower though, so far the biggest surprise in my life after removing a drain plug.

 

[Jeff Allen]

Ask 3 different people what’s the correct part # at the dealer and you'll probably get 3 different answers. I'll see if I can find the TSB that mentioned it at work tomorrow and let you know.

 

[Highbeam]

I read the TSB referring to the new Autotrac 2 blue fluid and it applies to the NV246 transfer case only. I don't have the autotrac feature and I have the NV243 transfer case. There is a tag on the transfer case itself that indicates this. The part # in the owners manual is clear. What wasn't clear until I dumped out the old fluid is just what the GM part # is equivalent to and in my case that sure appears to be atf. If you can find something that states I shouldn't use atf in MY transfer case and that that crazy red fluid that poored out of the t/c is in fact some special superlube other than atf then I would sure like to know.

Thanks

 

[Jeff Allen]

The red stuff that came out most likely was just plain ATF. I forgot to look into it at work today to see if it's compatible with the T/C you have. All it is synthetic ATF. If memory severs me (we know how that works now :) ) It was to fix some noise issues that GM was having with the T/C. I'll try and remember on Monday to look at it and let you know, I've got about a case of it in our stock room.

 

[Jeff Allen]

Found a TSB for you Highbeam, it's number is 99-04-21-006
I typed it out just the way we get it from GM, hope this helps.

IMPROVED AUTOMATIC TRANSFER CASE FLUID

Models
99-00 Cadillac Escalde
98-00 Chevy and GMC K/T
99-00 chevy and GMC L van
99-00 Olds Bravada

Date 9/99
CONDITION
Effective with vehical production in late june 0f 99, all active transfer cases on the above listed vehicals have been filled with Autotrak II fluid, P/N 12378508(P/N 10953626 in Canada) .This fluid has a light blue color rather than the red color of the previous fluids and is the next generation Automatic Transfer Case Fluid. The fluid also cantains a better friction modifier.

On the models listed above, the active transfer cases should only be serviced usuing P/N 12378508 (P/N 10953626 in Canada) ,even if the original fluid was the red Autotrak II fluid. The previous fluid and new fluid can be mixed or topped off if necessary. The new Autotrak II fluid will be the only available fluid once the supply of the old red Autotrak II fluid is exhausted on units older than stated above.

The Owner's Manuals and some service information will specify the incorrect fluid due to printing the information prior to the fluid being introduced.