Front Diff Oil??

[busta]

Okay I have been reading on here what to use for oil in the front diff and there are several different opinions...I just had my front diff fluid changed at my local mechanic and he just put regular 80 weight i think...i read on here that if i have the auto four wheel drive system then it needs to be a special type of oil you can only but through GM...is this correct???I have a 2000 GMC Sierra 4x4 w/ the auto 4 wheel drive system

 

sorry if i am repeating a thread here i just want to be clear on this

THANKS

[busta]

or are we talking two different parts here...is the special GM fluid (auto Trac??) for the transfer case and not the front diff??

[MS3DALE]

Yep,The "Auto-Trac II" fluid is for the transfer case.

The front diff. calls for regular 80W-90 (GM Part#89021671)

Although you can run synthetic if you want (GM Part#89021677)

[busta]

Yep,The "Auto-Trac II" fluid is for the transfer case.

The front diff. calls for regular 80W-90 (GM Part#89021671)

Although you can run synthetic if you want (GM Part#89021677)

 

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Yeah I called the GM dealer this morning to find out I was getting kind of worried...thanks for the info...but now i guess I need to get my transfer case fluid changed

[99silveradoz71]

When you change the t-case fluid, check to see what the fluid color is coming out. There was a tsb that said when you change your fluid, drain, refill and drive a few miles, then drain and refill again. I know that's the method I used when I changed mine the first time. I had red fluid from the factory. There's also been some suggestion that the blue juice may quiet down driveline clunk.

[busta]

When you change the t-case fluid, check to see what the fluid color is coming out.  There was a tsb that said when you change your fluid, drain, refill and drive a few miles, then drain and refill again.  I know that's the method I used when I changed mine the first time.  I had red fluid from the factory.  There's also been some suggestion that the blue juice may quiet down driveline clunk.

 

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I will try that out when I do it this weekend...only reason I didnt do my front and rear diff it was already in the shop for something else

[MS3DALE]

Yep,Thats why they developed the "Blue Juice" was for the driveline clunk at first.

(Then later they came out with a TSB to change to the nickel-plated driveshaft yoke for the clunk)

[busta]

so what is this blue juice we are talking about

[MS3DALE]

so what is this blue juice we are talking about

 

 

 

 

 

Its the "Auto-Trac II" fluid (GM Part#12378508)

Its now the only Auto-Trac fluid available,the red stuff is long discontinued.

[GM-Tech]

The Autotrak fluid has nothing to do with alleviating driveline clunk. It originally came out to correct transfer case shudder on turns on AWD vehicles, like the Bravada and Astro.

 

The driveshaft stop clunk is a different issue altogether. This is due to a binding of the yoke on the splines of the trans output shaft. On 2WD vehicles, that's corrected by lubricating the yoke with the special lubricant. In fact, I think that's its official name... "Special Lubricant." The nickle plated yoke is for 4WD vehicles with the stop clunk.

[99silveradoz71]

Ah, well tech has taken me to school. I know there was some tsb about that drain, fill, drive, drain, refill change for the first time. I just thought someone told me or posted about the Autotrac II being part of a series of possible treatments for driveline noise. Oh well, I had the splines greased a few times and eventually the nickel yoke, so she's quiet as can be now.