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New Front Dif.


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I changed my front diff fluid today with m1 75-90w.   The factory fluid however seems much thicker.   Did I use the right fluid???

Yes, M1 or other synthetic 75w-90 is what GM recommends, and the dealer actually put this in for me when they checked the growl out.

 

I think the std dino front diff gear oil is 80W-90 . . . . so I suppose that's maybe why it seemed thicker . . .

Just for completeness I was gonna post the P/N of the 75w-90 fluid the dealer used, but I can't find the service write-up . . . :banghead: I will locate it eventually and post the GM P/N for the synthetic, if anyone is interested.

 

All I can say is when I opened the drain plug, the stuff coming out looked, smelled, and tasted :D the same as the M1 I just topped off the rear diff with. So I did check back w/ parts, read the number off and had them tell me what it was - he said Mobil1 75w-90 synthetic, even though it's in a GM bottle.

 

My original OEM fluid, the dealer said, looked strangely brown, but no materials on the plug end, so that's why they changed it for me.

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My front diff makes a good amount of noise...

 

I changed the fluid recently at 26K miles. It was darker, but not bad at all. A good amount of "fuzzies" on the drain plug magnet... but I think it was acceptable. No big chunks - just a fine powder that almost dissolved in a rag.

 

I used M1 75/90 - My manual states that GM recommends synthetic up front. Something my '02 trucks manual did not...

 

Fill it til fluid is at the bottom of the fill-hole...

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My front diff makes a good amount of noise...

 

I changed the fluid recently at 26K miles.  It was darker, but not bad at all.  A good amount of "fuzzies" on the drain plug magnet... but I think it was acceptable.  No big chunks - just a fine powder that almost dissolved in a rag.

 

I used M1 75/90 - My manual states that GM recommends synthetic up front.  Something my '02 trucks manual did not...

 

Fill it til fluid is at the bottom of the fill-hole...

did you use a funnel?

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The M1 bottles, at least are thin and tall, and have nose that comes to a point that allows you to orient the bottle up there and squeeze it into the filler hole.

 

Of course that usually doesn't stop me from getting it all over the place anyway :banghead:

 

There are also pump kits that will attach to the threads if you take that nose off the top of the bottle - suppose that works too, but it's messy also at times, especially when having to clean it out afterwards.

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11,000 miles, never any front-end noise.

I thought these had synthetic from the factory.  :confused:

 

WW :cool:

 

I'm not sure about the '04/'05 SSS, but the 2 '03 trucks I've had, neither had synthetic front diff fluid from the factory.

 

Evidently, somewhere along the line, GM did change at least some of the front diffs to "synthetic-ready" is how I heard it. I saw a TSB - or maybe a note on GM Tech Link that indicated the front diff was synthetic ready if the plastic "vent hose" assembly, was white, rather than black. If white, it was OK. I noticed right away that the SSS diff vent hose assembly was white. But it still had dino diff flluid in it till service replaced it.

 

I also had an '03 std Silverado LS 4x4 and the breather tube assembly was black - it definitely had std dino fluid.

 

Found the write-up at Synthetic Front Axle Lubricant if anybody's interested. Lots of good info here, BTW.

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