After putting it off I got around to changing most of the fluids in my 2003 GMC Sierra HD 4X4. I put amsoil synthetic gear lube & both differentials & Dextron III in the transfer case & the partial exchange in the tranny. I also did the air & fuel filter. It went so well I plan to help the brother with his 2004 truck when I visit this weekend. The worst looking fluid was the front differential, a fair amount of shavings on the magnetic plug too. This truck has been lightly used the last few years with 64,000 miles currently. I know there are many that never check some of the fluids & then you have some that change every 2 years or so. I guess I fall right in the middle with much of this. I did check levels one other time, but this was the 1st change. Negligent or average?
