I have a 03 1500 silvy 4x4 with auto trac. My truck was impounded for four months (not my fault, dont let friends borrow your vehicle) and I want to swap out my tranny, transfer case, and rear end fluid. The question I have is can I use a synthetic fluid in all of them? If so does anyone have a recomendation on a good fluid? Also if anyone knows the fluid weights for each that would be helpfull as well.
Thanks

 

Yes you can use synthetic in everything with the exception of the Auto-Trac transfer case. Use the GM spec fluid in the transfer case. Is your truck a HD? If not which engine do you have?

I use Amsoil in everything except the transmission because I read that it is too slippery but I am not sure that it really is. Maybe in the 4L60E it is because that transmission is a little on the light side for our trucks. So yes you can use synthetic in everything but maybe not the best idea in the transmission if you are planning to make any large HP increases through performance mods and have the 4L60E.

Here is a link to the Amsoil Application Guide for a '03 1500 . Amsoil makes everything you need and they have very good synthetic products.

 

The rear end fluid can be replaced with synthetic, don't forget the additive for posi, if your truck has one. The Autotrac requires the special fluid from the dealer, it is synthetic. Manual transmission requires a special synthetic fluid from the dealer. Automatic Transmission I would call the dealer, I think (don't quote me) the fluid is synthetic.

 

No I have a light duty 1500 with 5.3.

 

royal purple has everything you need to do the fluids in your intire truck from the front diff to the rear diff with everything inbetween.

 

As an Amsoil dealer that currently drives a 1500 with a 5.3 I will suggest that you use the Severe Gear 75-90 in the diffs, no additive necessary, and the ATF in your transmission. Your transfer case will require you to use the GM auto-trac fluid. As far as motor oil I am currently using the Series 3000 HDD 5-30 and am very happy with the smoothness of the engine since switching from Mobil 1.

I have a number of people using this combo and they are very happy with it and the discounts I give them.

ken@modernoils.com