I've had several E4OD trannys R&R'd and the transfer case oil replaced when that happened. I have also had the rear axle seals go bad, so I had to replace the lube and limited-slip diff oil additive.

I never replaced the FRONT diff lube!! it has gone 190k miles. someone, somewhere, some time ago told me that if I didn't go into 4x4 mode it's not going to do much to the front diff. as far as wear and tear goes.

* is that true and what intervals before I should change it?

* is synthetic lube ok to use if I don't change it in both axles?

* do I still use the limited-slip additive with synthetic diff lube?

* does use of synthic lube mean longer change intervals?

Thanks for any help on these Questions!!

Ron