Front Differential Fluid

[spbutler]

My 2004 2500 HD Silverado manual calls for 80 - 90 for the front and 75 -90 synthetic for the rear. Would using

Royal Purple 75 -90 Synthetic in the front cause problems?

[Black02Silverado]

No problems at all. You can use 75w-90 in both front and rear.

[jwhjr]

I've been running 75-90 in the front diff on my 04 for close to 6 yrs now with no issues. Go for it!

[gmtech4]

the frt diffs up north here did not like the cold with 90w and blew up the pinions so there was a campaign to change every new 4X4 diff fluid to synthertic during the PDI

[spbutler]

Thanks for the responses. I changed the front to the Royal Purple and the rear to Lucas Synthetic since all the Royal Purple was gone. I'm glad I did as the front didn't look clean but the rear did.

Not sure if it was just the stock oil that was poor quality or something else could be wrong, contaminating the fluid, I see no visible leaks.

I also changed the transfer case to Mobil 1 Full Synthetic ATF and got the transmission flush at the dealer to Dexron VI.

[Nytemare]

A full synthetic drivetrain is so much nicer...you will definitely notice a difference in shifting smoothness and probably some fuel economy improvements.

 

I did when I switched.

[spbutler]

I did think it seemed smoother and any improvement on 8 - 9 mpg around town would help.

[Nytemare]

I did think it seemed smoother and any improvement on 8 - 9 mpg around town would help.

when I bough my truck first..I got 450km per tank...I got a tune and it went up to 550km. Than I went with Royal purple in everything and it increased to 575 guaranteed, and I have gotten slightly over 600 on occasion. This is city/highway combined...so depending on how much highway depends if i get over 600.

 

The difference in price of fuel and royal purple oil just about makes up the difference, but I get royal purple at cost.

 

Yes...at 5 bucks + a gallon for 94 octane...every little bit counts.

[bossier62guy]

Thanks for the responses. I changed the front to the Royal Purple and the rear to Lucas Synthetic since all the Royal Purple was gone. I'm glad I did as the front didn't look clean but the rear did.

Not sure if it was just the stock oil that was poor quality or something else could be wrong, contaminating the fluid, I see no visible leaks.

I also changed the transfer case to Mobil 1 Full Synthetic ATF and got the transmission flush at the dealer to Dexron VI.

 

Isn't the transfer case supposed to be filled w/ the GM stuff only? Or maybe it's a manual transfer case....hmmm.

[Nytemare]

Anything that calls for Dexron (I, II, III) can be substituted with a synthetic that meets the Dexron standards. Its written on the back of the bottle if its compatible.

[bossier62guy]

Anything that calls for Dexron (I, II, III) can be substituted with a synthetic that meets the Dexron standards. Its written on the back of the bottle if its compatible.

 

Did you actually read what I typed? Obviously he has a manual transfer case.....

[zaac]

Anything that calls for Dexron (I, II, III) can be substituted with a synthetic that meets the Dexron standards. Its written on the back of the bottle if its compatible.

 

Did you actually read what I typed? Obviously he has a manual transfer case.....

 

Yeah, he has a 3/4 ton. Don't think they come with the auto 4x4.

[Nytemare]

Even in the Auto Xfer case man.

 

The difference in an auto and a manual is the auto has a motor that shifts it. Its basically the same Xfer case.

 

Or do you mean an the autotrack Xfer case...because that's a full time AWD Xfer case..and that's different.

[bossier62guy]

Even in the Auto Xfer case man.

 

The difference in an auto and a manual is the auto has a motor that shifts it. Its basically the same Xfer case.

 

Or do you mean an the autotrack Xfer case...because that's a full time AWD Xfer case..and that's different.

 

The auto transfer case in my truck takes the autotrak fluid.....sounds like he's good to go though.

[zaac]

Even in the Auto Xfer case man.

Hey, I didn't know that. I thought if I didn't use Autotrak II fluid I would ruin the TC for sure.