trhs75

The owner's manual for my 99 RX300 recommends 90W oil for transfer case and rear diff for outside temps over zero degrees Fahrenheit, and 80W-90 for below zero. Obviously, I'm not going to change the oil every season. (I'm thinking of using all-synthetic, as I do for engine oil.) Does anyone know which weight is generally recommended? I live in Iowa, so we see temperature extremes each way!

thomas1

I have changed twice, oncle with Mobil synthetic 75-90 and second time with royal purple 75-90. Works fine last a long time...

Noypi

Hi I used redline syntetic 75-90, it seem to be fine.

Lexmex

75W90, I use Royal Purple, but take your pick Amsoil, Mobil 1, Redline are also good gear oils.

lexus114

I thought the transfer case uses the transmissions fluid,and the front & rear diff. use the gear lube? If not, then i`m all confused.

Lexmex

Don't worry, I will explain with some photos now.

Lexmex

Rear differential at top of picture (only if you have AWD) uses .9 L of gear fluid.

Lexmex

Transfer case (and only if you have AWD) also uses .9 L of gear fluid.

Lexmex

Now many switch the terms front differential and transfer case. This is ok, just as long as you know what is what.

For me, this is the front differential on the left and to the right is the tranny pan. Although they have separate drain plugs, BOTH are filled through the transmission dipstick hole on top. The front differential and the rest of the transmission are interconnected.

They only use ATF fluid, not gear fluid.

Lexmex

Here is the rear differential from the bottom (blue square).

Lexmex

In this photo under the engine, blue square is the transfer case (uses gear fluid) and the red circle is the front differential that uses ATF.

salimshah

Correct names are:

Transmission Transfluid
Transaxle Transfluid (same fill via transmission dip stick)

Then the
front / rear differential [if equipped]


The again I am bad in terminology

Salim

trhs75

I appreciate everyone's help. Thanks! Pics will help when I actually get under there, too.

sarah

Hi!

Do you have the above photo in a much larger size?

I'm currently having a problem. I went to a shop to ask them to change the rear differential oil and the transfer case oil, both of which use gear oil.

However, I suspect a mechanic opened the front differential drain hole and drined out some of the ATF. (the transmission and the front transmission share the same ATF.

He then opened the front differential fill-hole and filled it with gear oil. In fact, I do not think he know the difference between the transfer case and the front differential.

The reason for my suspicion is that I looked under my AWD RX300 and noticed that the tranfer case had no signs of having been touched at all. It's got the usual road dust, but no finger prints and no oil smudges, no nothing. On the other hand, the front differential drain hole was greasy, like someone just drained fluid out and even fingerprints...

Just so you guys know that I know what I'm talking about. The transfer case is near the engine oil pan. The front differential drain hole is next to the transmisson fluid pan.

The strange thing is that I pulled the ATF dipstick and the ATF is still pretty clean, having been changed a few weeks earlier.

I'm so confused right now. The mechanic still insist that he drained and then refilled the transfer case.

Lexmex

I don't think I have a bigger photo of above, but it came out of this thread. I did the drain and fill three times in that thread so there are plenty of photos of the process,

https://www.clublexus.com/forums/rx-...sfer-case.html