D4 Axle Code on '98 AWD

[X6StringerX]

I was wondering if this code applied to both the rear and front differentials? I know it means 3.73 limited-slip. Of course, the front and rear both HAVE to be the same ratio, but is the front limited-slip as well? I'm a little unclear on this and I'm planning on changing the fluid in both differentials to full synthetic soon. I've read that some synthetics already include the limited-slip additive and I didn't want to use the wrong kind of fluid in either of the differentials.

Also, any recommendations for gear oil? Amsoil looks promising, but what weights and viscosities are recommended for our rides?

 

[410Fortune]

no truck came from the factory with front limited slip
AWD and 4x4 MUST have the same gear ratio in both differentials otherwise the drivetrain would explode.

You have 3.73, with a rear limited slip.
It is NEVER a bad idea to add friction modifier to gear lube, even in a non limited slip diff, it helps prevent "foaming"