Synthetic Fluids

[Smoker_98]

I have some conflicting info on starting to run synthetic fluids on higher mileage vehicles. My truck has just over 80k on it and as far as I know has not ever had anything but regular fluids in it. I was going to flush everything here soon and do all synthetics. What do you all think? I have heard bad things about making the swap after higher miles.

[DUALLS]

You can do it.It won't cause a problem,just use a quality synthetic.The differentals should have synthetic anyway from the factory.

[Smoker_98]

You can do it.It won't cause a problem,just use a quality synthetic.The differentals should have synthetic anyway from the factory.

Thanks, I was going to go with Mobile, what is a good synthetic for the trans? I was going to flush do a new filter then fill up with synthetic. How long is the diff fluid good for? As far as I can see it is dry as a bone, no leaks at all.

[tanz45]

I use Mobile 1 5w30 for motor, valvoline Synthetic in tranny, Mobile 1 90/140 in Diffs w/addative, regular atf in T-Case.

Some say not to use synthetic in the tranny because it will clean out all the junk. Just make sure you use a line/converter cleaner. Comes in a pressurized can that you hook up the cooling line and pump it through the system.

[Smoker_98]

I use Mobile 1 5w30 for motor, valvoline Synthetic in tranny, Mobile 1 90/140 in Diffs w/addative, regular atf in T-Case.

Some say not to use synthetic in the tranny because it will clean out all the junk. Just make sure you use a line/converter cleaner. Comes in a pressurized can that you hook up the cooling line and pump it through the system.

Thanks, I was going to hook up the trans to the BG machine at my friends shop and do a full tranny flush first. Then fill it up with synthetic, would this be acceptable? Do you know what the recommended change on the diff oil is? It is a 4wd Z71.

[tanz45]

Used those flush machines before, I never had any issues with them.

Diff fluid, prob 80-100K. Depends I guess on what you are doing with it.

[Smoker_98]

Used those flush machines before, I never had any issues with them.

Diff fluid, prob 80-100K. Depends I guess on what you are doing with it.

Do you know if the BG semi syntheitc trans fluid is any good? I can get it at cost for el cheapo.

To all the rest of you guys thanks! Cheers!

[SLO TRUCK]

I use Royal Purple in the my whole truck. Engine RP 5w30, RP ATF, and RP 90wt in the diff

[GRsilverado]

+1 ^ i only use royal purple for my whole truck along with my other cars

[Ydtrack]

I switched my truck over to all synthetic fluids after I bought it at 70k miles. I run Amsoil in everything and don't have any problems.