Have a 2009 AWD RX-350[72,000 miles].....can't find any information on when to change the transfer case and differential fluids.....have heard fluids never need changing....my dealer wants to charge $280. to change both fluids....one[1] quart each of a synthetic oil....anyone have an experience with this situation...thanks.

 

welcome to CL...if you do a search, you will find this one:

https://www.clublexus.com/forums/rx-...ntial-oil.html

 

If i remember correctly, the transmission and transfer case are sealed assemblies. You cant really just drop the fluid and change them like that unless under extreme conditions.

the rear differential you can though. There are some people who say differently on what fluid to use. there is differential fluid but ive also heard people using ATF. Ive never done it tho so I will let someone else chime in on what fluids to use

 

People have different perspective on fluids and many people believes that there is such thing called lifetime fluids. I did drain and fill for ATF with my 08 at 60K and I am going to change the transfer case as well as rear differential fluids soon. Bot uses 80W-90 gear oil based on the spec. However for ATM I brought Toyota WS ATM fluid based on the spec.

 

My favorite gear lube is the Amsoil GL-5 75W-90 Long Life Synthetic Gear Lube. 0.9qt for front (actually the transfer case) and rear diff, so 2 qts for ~$25. I highly recommend picking up a Lowe's Kobalt Extreme Access 15/16 - 24mm spline socket. Use a 7/8 wrench to turn the socket (for the front xfer case). The rear diff uses Allen head wrenches (10mm if I remember right).

I recommend doing this service just after the car has been driven to normal operating temp as the OEM fluid is NOT synthetic and is very thick (will drain better and far quicker!) Also, unbolt the filler plug first in case you have any problems getting them broken loose...so you are not stuck with empty diffs. Oh you will also want a Allen head socket for the rear diff as those thing were a bugger to bust loose. Don't forget to clean the drain plug magnets too :-)

This service is not difficult. It's easier than I thought it would be once I got that extreme access socket. So save $250 and do it yourself in about an hour.

 

I got my car used in May and that was the the first thing I changed out(ATF, TC and rear diff). The bolts were a pain to crack open but doable.

I'm about to do an oil change and will change out 3.7qt of ATF out again. I should be good for awhile after this. The transmission did feel a lot smoother after I drain/fill the ATF, even my wife felt the difference.

 

On my 04 RX330, I used 80W-90 gear oil as that is what my local Lexus dealer said they used when they performed the service. It takes maybe 20 minutes or so to do if you can get under the car easily. It's not difficult to do, but if you are not sure of your mechanical abilities, I am sure you can find an independent shop to do it for you for $30-40 (or less) plus fluids. Bottom line, don't pay $280 to have it changed.