I just had a lot of maintenance work done on my '08 RX 350 AWD at the Lexus dealer. I have 137,000 miles. Asked them to replace front and rear differential oils, transfer case oil and a drain and fill on the transmission fluid. I know about the lifetime fluid, but I do a lot of miles and plan on keeping it for a long time so it's cheap insurance.

The Lexus rep told me the Transmission fluid and transfer case oil are the same thing. By draining and refilling the transmission, this takes care of the transfer case as well. However, I see in the manual they specifically list to check the transfer case oil and transmission fluid seperately. What's the deal? Are these one in the same?

 

I know on the RX300 the transfer case fluid is the same as the Tranny fluid...not sure on the RX350...

 

For the front, they are one in the same. If you are draining and filling the transmission you are also taking care of the front differential. The rear differential needs done separate.

Like many topics, this one has been discussed many times previous. You can use the search features for Club Lexus to find these existing threads for more information.

 

That's incorrect.

The transmission shares fluid with the front differential in the RX300, not transfer case. The transfer case and rear differential take gear oil and have their separate fill and drain plugs.

 

I second that since I've done the fluid changes myself a couple of months ago and the rear diff fluid is the same as the transfer case fluid (and they are separate entities and different size drain/fill plugs), however the transmission fluid and the front diff share the same fluid (and those are connected).

Long story short, please, see the following thread:
https://www.clublexus.com/forums/rx-...-interval.html

 

Aw yes I forget, the differential is shared with the tranny...My bad I was thinking assembly correctly but not the word...(transfer case).