Front axle mustard?

[csimo]

We all know the famous rear axle fluid smells like grape juice, but I just changed my front axle fluid today. It looked like mustard! Thick and yellow.

Anybody else had this "situation" with the front axle fluid?

I replaced it with Red Line 75w-90 GL-5+ synthetic, but I think I will need to change it again to flush the rest of the mustard out.

-Joe
2002 Silverado D/A CC SB

[Lone Eagle]

When I changed mine a couple months ago it came out the color of split-pea soup. It looked gritty so I saved it in a transparent milk jug. It took quite awhile but the grit settled to the bottom leaving the oil on top. It looked and smelled like gear oil. The jug wasn't clear enough to get a picture to post so I transferred it to a glass jar just this morning. I would sure recommend everyone change theirs ASAP. Later! Lone Eagle

[Turbo Al]

I have posted numerous times on the NEED to change the frount diff oil. Please do it at 5,000 miles or 500 miles loaded (in 4x4) -- whichever comes first. I think this is the most common oversight 4x4 owners do, not changing the transfercase oil would probably be second.
Also I think the oils that colour from GM not because it's contaminated from external sources.

[01_Duramax_Dually]

Turbo AL,
Well I have not ran my truck in 4wd much more than 30 miles. So I should wait until about 500 miles or should I have changed it at 5000 miles regular 2wd driving? If so, I am 15K miles over that limit..Holy Schnikes!@!!!!

OK, so where is the drain and fill plug for the front?
How many qts?

What about the transfer case...?

Need info, will perform the service ASAP.

[Mic]

The front diff. has the same setup as the rear, drain and fill plugs. Will have to remove the skid plate (if equipped).

Transfer case was a breeze as well. two plugs one to drain and top one to fill. the upper was hidden a bit, unless you have the truck on a lift. I just worked on the floor.

[01_Duramax_Dually]

MIC,
Hey thanks and I will plan on that this week.

Does anybody know the fluid amounts for the Transfer case and Front diff?

Are they the same fluid?

Sorry to ask a dumb question like that, Just felt it easier then going and getting the manual....

[Mic]

01_Duramax_Dually

I can check on the amount (in the manual), but as for fluid I used sythetic ATF for the transfer case and 75W-90 synthetic for the front (same as the rear)

[Kanuck]

Hi Guys
Depends on the transfer case as to which oil you use.
NV 261 Manual Transfer case RPO NP2 uses 2 quarts of Dexron 3.
NV 263 Selectable Transfer case RPO NP1 uses 2 quarts of Dexron 3.
NV 246 Automatic Transfer case RPO NP8 uses 2 quarts of Auto Trac 2 fluid.
Front axle lube is PN 1052271 or SAE 80W-90 GL5
Kanuck

[Turbo Al]

OK guys I did forget one important point. I changed the frount diff oil to syn. at the 5,000 mile mark because it had over 500 miles of running time. I WOULD NOT change it over to syn. until it has 500 miles on it. Just my opionion but I think it should be broken in on regular gear oil.
So go ahead and change oil at 5,000 miles, just put reg gear oil in untill it has some running time on it.

[01_Duramax_Dually]

Turbo AL,
I checked my owners manual last night and like the rearend, the manual states nothing about amount of fluid required. I am gathering that GM does not want you to do this...Matter of fact when you ask the service department they do not know how much either, they said "We fill it until it is full" But they can sure bill you for a certain amount...

Anybody know fluid amount for front diff?

I have the NP8 electronic controlled Transfer case, so I will follow Kanucks info.

Thanks and await info

Jeff

[pullinpower]

I have 25k on mine and havent changed it yet going to today before the "dega" trip.How many quarts does it hold?

[Jake99Z71]

pullinpower,
I think I put about 2 quarts in it. To be safe just make sure to have 3qts on hand. I forgot to record this after I did the change for future reference.

[pullinpower]

Thanks jake99Z71,I bet there are alot of people changing the front diff. oil out after these "mustard" sightings?

[Jake99Z71]

Yeah, I did mine when I had 10K on it. I now have 26K. I'll probably do it again at 30K just to help get rid of the nasty residue that doesn't drain out since we can't wipe it out like the rear. Y/W

[01_Duramax_Dually]

Changed out the front Diff today, looked very much like rearend, had slight yellowish look but nothing Mustard colored.

Anyway, takes 2 1/4 qts to fill. I drained out and measured what was factory filled which was just a scoosh over 2 qts, when I filled it just started to roll out at 2 1/4. I went with Redline Synthetic 75w-90. I use their Diesel Synthetic Motor oil and am having excellent results.

I feel better now...

[Lone Eagle]

TurboAl, The oil that came out of the front of my 2500HD is different than any dino oil I have seen. This is my fourth Chevy with the aluminum differencial. I put Mobile I in all of them. My 2500 only had about 1.25 qts. in it. All my trucks had gritty oil come out. The grit looked like aluminum particles. My 89 had both axle seals leaking at 18K. I wiped the oil off with a clean white rag and it was aluminum. Since the truck was out of warantee I decided to change the oil and watch it. The seals stopped leaking immediately. Two quarts will fill it. For those that have not changed your's yet you can buy a neat bottle extention with built in valve to make filling easy. My oil is still green and settleing but it has a half inch of something dark grey in the bottom of the jar. I will get a picture when it is done. Later! Lone Eagle

[Lone Eagle]

01_Duramax_Dually, I don't think any of the 2500HD or your 3500 came with Auto Trac. This was covered thourghly a few months back. You can find it with the "search function". Later! Lone Eagle

[pullinpower]

Thats the dark gray gunk that I wiped off my magnet.Seems like it could be "clutch dust" from the clutch pack in the front end.

[01_Duramax_Dually]

Since people are using ATF in the transfer case can I use the Allison Transdyn synthetic ATF? I have a couple of gallons.

The owners manual is not clear.

Any thoughts?

Lone Eagle. Yes you are 100% correct, I do not have the Auto Trac...I just have the "On the fly, 4wd" option that Gm has named it....Essentially electronically controlled transfer case.

Regards

[hoot]

Just did mine yesterday because of this post. It was Goldens Brown Mustard color but had good consistancy. Not much on the magnet. 26,000 miles.

I used Red Line 70-90 full synthetic racing gear oil.

The color could be a couple of things. Pattern compound from when the gears were set up or purposefully colored to see if it was changed later on.