Transfer case fluid change

weo38 · 03-14-2007, 02:23 PM

I am preparing to do a fluid change on my 04 Silverado. I plan on doing the tranny, both diffs and the transfer case. I am going to use synthetic oils and lubes but the manufacturer has no recommendation for my transfer case (NVG 246-NP8). I have the push button 4WD. They list a GM part number (12378508) for this transfer case. I tried looking the part number up online but got no definitive answers. Any thoughts on this? I was going to see if there was a tag on the transfer case to see what it says for lube. Thanks.

taber.gmc · 03-14-2007, 02:51 PM

I had the same problem with my 2000 GMC Sierra. The manual had no recommendations for the transfer case. I called a dealership, and they told me to use Dexron III (Transmission Fluid). On the other hand, our transfer case on the Duramax has to use super expensive GM Transfer Case lube.

**shadams** · 03-14-2007, 03:07 PM

Can vary depending on type of t/case. If you want to PM me the last 8 of your VIN I can tell you which. Some use transmission fluid, some use what GM calls Autotrac fluid, and some use manual transmission/transfer case fluid.

DOH! See you listed you case, hold on.

OK, the fluid part # you listed is for Autotrak-II fluid which goes in that t/case. Is that the info you wanted?

weo38 · 03-14-2007, 03:24 PM

shadams here is the last 8 of my vin just in case my assumptions were wrong: 4Z273410

howpeculiar · 03-14-2007, 05:29 PM

The blue transfer case fluid can be sourced at GM, you should need 2qt, and it isn't expensive.

weo38 · 03-15-2007, 09:41 AM

Thanks for the info. Now that I have that cleared up how do I tell which ring gear I have in the rear end? My truck has 3.73 ratio. And how do I tell which tranny pan i have on my truck deep or shallow and if it is a reusable gasket?

**GMCSonoma** · 03-15-2007, 09:46 AM

You have the 8.6" rear diff with Posi & 3.73 ratio...both diffs use 75w90 synthetic...

Your transmission is a deep pan...oe# for the transmission service kit is# 24208576.

You will need two liters of the Auto Trac fluid for the tcase....#12378508

Headymusk · 04-17-2008, 08:48 AM

In my "2001 Diesel Supplement" manual it says for "manual transfer case" you should use Dexron III. For an "automatic transfer case" use Auto-Trak II. I was confused at first then after a couple of days of research I found out that the meaning of automatic trasfer case was if you have a 'Auto 4X4" button in your truck. In which I do not recall ever seeing one in a full size truck. I have however had one in my wife's 2001 ZR2 Blazer. Weather this is differnt because my truck is a diesel, I have no idea, but manual is manual and automatic is automatic.

03-14-2007, 02:23 PM	#1 (permalink)
weo38 1.8 Liter ECOTEC Join Date: Mar 2007 Location: Kendall, NY Drives: 2004 Silverado Z-71 ECSB 2007 Ski-Doo 500SS Posts: 30	Transfer case fluid change I am preparing to do a fluid change on my 04 Silverado. I plan on doing the tranny, both diffs and the transfer case. I am going to use synthetic oils and lubes but the manufacturer has no recommendation for my transfer case (NVG 246-NP8). I have the push button 4WD. They list a GM part number (12378508) for this transfer case. I tried looking the part number up online but got no definitive answers. Any thoughts on this? I was going to see if there was a tag on the transfer case to see what it says for lube. Thanks.

03-14-2007, 02:51 PM	#2 (permalink)
taber.gmc 1.4 Liter Turbocharged ECOTEC Join Date: Jul 2006 Location: Stillwater, Oklahoma Drives: 2000 GMC Sierra Z71 Posts: 77	Re: Transfer case fluid change I had the same problem with my 2000 GMC Sierra. The manual had no recommendations for the transfer case. I called a dealership, and they told me to use Dexron III (Transmission Fluid). On the other hand, our transfer case on the Duramax has to use super expensive GM Transfer Case lube. __________________ Current Ride: 2000 GMC Sierra Z71 Previous Ride: 1989 Toyota Pickup Farm Vehicles: 2006 Chevy Silverado 3500 2001 Chevy Silverado 2500HD 1992 Chevy K2500HD

03-14-2007, 03:07 PM	#3 (permalink)
shadams GMI Staff Member Join Date: Apr 2005 Location: Texas Hill Country Drives: 09' G8 GT 08' GMC X-CAB Posts: 3,347	Re: Transfer case fluid change Can vary depending on type of t/case. If you want to PM me the last 8 of your VIN I can tell you which. Some use transmission fluid, some use what GM calls Autotrac fluid, and some use manual transmission/transfer case fluid. DOH! See you listed you case, hold on. OK, the fluid part # you listed is for Autotrak-II fluid which goes in that t/case. Is that the info you wanted? __________________ 2008 GMC Sierra XCab Z-71 4x4 Onyx Black 2009 G8 GT Magnetic Gray GM/ASE Certified Service Consultant MOE Platinum 04-05-06-07-08 "Contrary to common belief, planning is complicated and is not run by complete idiots, so you'll just have to trust that the decisions were made on good information that's not made available to you." Last edited by shadams : 03-14-2007 at 03:41 PM.

03-14-2007, 03:24 PM	#4 (permalink)
weo38 1.8 Liter ECOTEC Join Date: Mar 2007 Location: Kendall, NY Drives: 2004 Silverado Z-71 ECSB 2007 Ski-Doo 500SS Posts: 30	Re: Transfer case fluid change shadams here is the last 8 of my vin just in case my assumptions were wrong: 4Z273410

03-14-2007, 05:29 PM	#5 (permalink)
howpeculiar 2.4 Liter SIDI ECOTEC Join Date: Jul 2006 Posts: 368	Re: Transfer case fluid change The blue transfer case fluid can be sourced at GM, you should need 2qt, and it isn't expensive.

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03-15-2007, 09:41 AM	#6 (permalink)
weo38 1.8 Liter ECOTEC Join Date: Mar 2007 Location: Kendall, NY Drives: 2004 Silverado Z-71 ECSB 2007 Ski-Doo 500SS Posts: 30	Re: Transfer case fluid change Thanks for the info. Now that I have that cleared up how do I tell which ring gear I have in the rear end? My truck has 3.73 ratio. And how do I tell which tranny pan i have on my truck deep or shallow and if it is a reusable gasket? Last edited by weo38 : 03-15-2007 at 09:45 AM.

03-15-2007, 09:46 AM	#7 (permalink)
GMCSonoma GMI Staff Member Join Date: Sep 2004 Posts: 10,053	Re: Transfer case fluid change You have the 8.6" rear diff with Posi & 3.73 ratio...both diffs use 75w90 synthetic... Your transmission is a deep pan...oe# for the transmission service kit is# 24208576. You will need two liters of the Auto Trac fluid for the tcase....#12378508 __________________ GM dealer parts manager...for a lot of years! *Please post all tech questions to the GMI Tech Forum, not my message box! Thanks! Last edited by GMCSonoma : 03-15-2007 at 09:49 AM.*

04-17-2008, 08:48 AM	#8 (permalink)
Headymusk Walking Join Date: Apr 2008 Posts: 1	Re: Transfer case fluid change In my "2001 Diesel Supplement" manual it says for "manual transfer case" you should use Dexron III. For an "automatic transfer case" use Auto-Trak II. I was confused at first then after a couple of days of research I found out that the meaning of automatic trasfer case was if you have a 'Auto 4X4" button in your truck. In which I do not recall ever seeing one in a full size truck. I have however had one in my wife's 2001 ZR2 Blazer. Weather this is differnt because my truck is a diesel, I have no idea, but manual is manual and automatic is automatic. Last edited by Headymusk : 04-17-2008 at 09:19 AM.

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