Wheatley

iTrader: (12)

Amsoil

Mort

Another vote for Amsoil. I use 5W30 ASL and a Baldwin filter.

one03sierra

iTrader: (1)

royal purple and a gm filter

Leroy_454

Valvoline 10W-30 and givin it hell!

tooquick2beslo

Same here. Its good to use the GM filter. They have the check valve in them.

James B.

iTrader: (1)

copy/paste of my full fluid breakdown:

Currently:
- Mobil-1 10W-30 in the crankcase with a Mobil-1 filter.
- Valvoline Dexron-III ATF in the Trans.
- GM #12346190 Synthetic Manual Trans Fluid in the Gear Vendors
- GM #12345977 80W-90 non-synthetic Axle Lubricant with GM #1052358 friction modifier.
- GM #12377967 DOT3 Delco Supreme Brake Fluid
- GM #89020661 Power Steering Fluid
- Prestone Dex-Cool 50/50% with distilled water in the Radiator
- Castrol Syntec 5W-50 in the Whipple

With my next oil change I will be switching to Lucas 15/40 High TBN Truck Oil with the Mobil-1 Filter.

02sierraz71_5.3

iTrader: (2)

not to steal the thread
do the oil filter magnets work?? or is this another tornado they seem like a good idea

GMCHammer

iTrader: (4)

Mobil 1 Synthetic 5-30

slamed 04 silverado

Amsoil, Redline or Mobil 1 10/30.

TG02Z71

iTrader: (2)

I have been using Mobil1 5w30 since 4000 mile mark in the cold and Mobil1 15w50 extreme driving formula in the summer. Still don't know if I'm going to use the 15w50 now that I have the STS kit on. Never had a problem with the Mobil1 and have been using it on my last three trucks.