I am thinking about switching my trans and diff fluid over to full synthetic when I hit 100,000k miles. I already use Royal Purple in the engine, but I would like to know from you all on here what type and weights of synthetic to use for my trans and diff's. Thanks!

-Tim-

 

If I am not mistaken these transmissions need ATF+4 fluid.. and your choices are limited.

When I did my rear diff, I went with Valvoline full synth.

 

IIRC your 2005 diff require synthetic GL-5 rated gear oil and cane from the factory with synthetic gear oil and the trans uses ATF+4.

 

My personal choice is AMSOIL, http://www.amsoil.com/

 

Many of the companies that offer high performance syn fluids label them without a specific weight on the bottle but I'm sure you could find out what weight it is before pouring it in.