Hey Fellas I bought a used 2003 Silverado back in February so far it runs good it just has a few little things to fix. My question is the diffs. Can I run I run Mobil 1 gear fluid or should I get Chev's synthetic??

 

Doesn't matter as long as it is the right weight and it is full synthetic. I used Mobil in the rear, Lucas on the front and Valvoline High Milelage stuff in the transfer case and transmission.

 

Do you or does any one the correct weight to put in each differential and the transfer case I plan on draining the fluid in all three if these and putting in new.

 

Trans and transfer case is Dextron. Rear diff is 75W90 synthetic gear oil, and front I believe is the same but you do not need to use synthetic.

 

Thanks for the info I appreciate it..

 

its gl5 (i think) that goes in the rear...any brand is ok,just make sure its approved.

and..ONLY the gm stuff is grape scented!

 

Argon - I have heard that there is a special fluid for the transfer case that you can only get from the dealer. Do you only recommend using the GM fluid and not any other aftermarket brand?

 

ok,the poop..it is illegal for a carmaker to say "use gm fluid..or exxon oil,etc"/..all they can do is set standards and say to ,meet it..

the rear end oil in a 99 and up is gl5 synthetic...as long as it meets that,its ok.

transfer case...they change those a lot...read your owners manual for specifics...there are probably 5 different cases for the 2008 model year...saome take atf...some synthetic.

so yes,i'd buy gm...not because its better...but because i'd know i was putting the correct stuff in

 

Find the model number for your transfer case and either look it up online or buy a service book. (Argon might be able to find it too). But there are around 3-4 different transfer cases I believe. Some require that "special stuff", others do not. My 99 takes plain old red stuff.