i'm just bought 2007 flexfuel sub with 50k miles on it and looking to flush trany, breaks, diff oil, transfer case and coolant.
For engine i'm using royal purple 5w30 full synt. oil

any recommendations ?


Thx.

 

well from what I have seen, tranny fluid is tranny fluid. The rear end I use mobile 1 75-90. The fluid for your tansfer case depends on your truck. I think awd will take trans fluid and 4wd would take autotrak. I have always just used dexcool, but have herd from some it is crosive, not sure how true that is. They make green coolant now that will last just as long as dexcool but you can not mix them so you would have to do a really good flush.

 

In your owners manual on page 563 there is a list of our recommended luibricants and fluids that may prove to be useful. This list goes to page 565 and on page 566 there is a chart of normal replacement parts and their part numbers that should keep you in the know on what to get when you need to. I hope that helps!

Jeff Morris, Chevrolet Customer Service

 

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Do all of the above. Use a synthetic oil other than Royal Purple.

 

For the diffs, I like Lubrication Engineers 9919 Synolec. I even use it in gear boxes of my tractor. For years, I used Mobil 1 in the diffs of my Turbodiesel Ram, but switched to the LE Synolec after seeing a demonstration.

Engine oil, for years I've used Mobil 1 Truck & SUV, which is rebadged Mobil 1 Delvac. Easy to find, long drain intervals, works for me.

Transfer case, I use the GM lube.

 

hmmm, why not Royal purple ??? Engine stop knocking in cold start after change. It's little bit expensive (about 9$ p quart) but give you 0.5 MPG better mileage. Also, I'm installed K&N cold air intake. It makes engine little bit louder, but give you 1.5 MPG better mileage. Now i'm thinking to change spark plugs for pulstar iridium - up to 12% more HP, torque and better fuel efficient. Hmmm, Looks like Royal purple is the best oil if you go for performance and efficiency (there was dyno test which proved 14 HP after they replaced OEM oils for Roya purple.
Oki fellas, thx for help Ill keep you updated

* here is my list of oils, fluids and spark plugs, i'm going to change:
spark plugs Pulstar iridium electrode Transmission fluid Royal purple Max ATF
differencial oil Royal purple Max gear 75-90
Trasfer case Royal purple Synchromax

 

Would be interested at what rpm the 12% and 14 hp were realized at.

 

Every single fluid you have selected is not approved by GM for use in your vehicle. Claiming a 14 hp improvement on a dyno by only replacing the oil with Royal Purple is not possible and whoever told you is misinformed.

I use the following oils for my vehicle...

Engine - Synthetic 5w30 - Castrol, Mobil 1, etc. Royal Purple would be fine, but not worth the extra $.
Transfer Case - GM AutoTrak II ONLY - This is the only approved oil. Royal Purple is not approved and the friction modifiers in the Synchomesh will not work will with the clutches in this transfer case.
Transmission - Synthetic DEXRON VI - All trans fluid must be DEXRON VI specification. Royal Purple is not.
Axles - Amsoil SVG 75w90 - Not approved by GM, but Amsoil will cover if the failure is lubrication caused and not covered by GM.

The only thing Royal Purple is going to do for you is to separate more green from you wallet.

 

X2. royal purple, I have herd was a good oil. I have never used it, But seems to be a waste. it just cost to much. Anyone know why a AWD says to use trans fluid and not the autotrak like 4X4. On my Awd I can still put it in 4lo.