Lexmex

There are some good posts already about changing the transmission fluid. I wanted to pay more attention this time to the front differential. Also keep in mind, I have an AWD RX300, which will differ in the filling details for the ATF fluid.

Lexmex

Normally, I use 4.5 bottles of the Toyota Type-IV. Since I have no Lexus in Mexico, a nearby Toyota dealer readily sells this and has plenty of it in inventory.

Antonio Jr. first uses a mallet to punch in the hex wrench into position on the tranny pan. This time around we didn't remove the tranny pan unlike previous occasions since the fluid is practically new. Next time I do remove the pan, I will take a picture.

Lexmex

This is the old tranny fluid, but is red in color meaning it is still fresh.

Lexmex

There was a small amount of buildup (gray) on the tranny plug.

Lexmex

Now, let's turn our attention to the front differential. Many of you have seen this picture before, with the tranny drain plug on the right and the front differential drain plug on the left.

Lexmex

Antonio Jr. then took off the front differential drain plug.

Lexmex

And this was what came out, some red ATF. The drain plug itself was not dirty at all.

Lexmex

Now, we have been talking about in the forum that the front differential and transmission (even though they have two drain plugs), that they both get filled from the same area, the hole where the transmission fluid dipstick goes.

However, Antonio Jr. wanted to make sure.

Did you know we found on the very back side of the transmission a front differential filler plug?(see photo)

We actually removed it, since it was so difficult to take a picture of the actual location. We also poured some of the old fluid into that hole where the filler plug was found and sure enough it came out the bottom.

However, also wanted to make sure that the transmission ATF and the front differential ATF were indeed connected.

First, we put the transmission plug back on and left only the differential drain plug off. We poured some old fluid down the dipstick hole. Sure enough, the fluid poured out of the front differential drain hole.

What does all this mean?

You can pull both the drain plugs on the transmission and the front differential and replace the fluid for both simply by pouring ATF fluid back through the dipstick hole.

However, Antonio Jr. found out something else.

After we put all the plugs back on. We poured in 4 bottles of ATF. We then turned on the RX and let the motor run putting it into its gears. Now, normally on my AWD, Antonio Jr. only has to add .5 bottles more to get the level right. This time, he had to add 1 full bottle. Thus, that extra fluid in the front differential was likely the difference.

I still don't know what the purpose of the filler hole was on the back for the front differential.

BTW, I wanted to mention my RX had 107K miles on it.

duane

Lexmex,

I'm a new RX300 owner and I do all of my own work. Your posts and pictures are very helpful. Thanks for taking the time to post your work

Duane

TunedRX300

Kudos to all owners who DIY on simple maintenance work. The rear fill plug may be used to dry-fill tranny since tranny fill hole is small and it takes forever to fill 9.8 quarts of ATF. Every second counts when Toyota is shoving as many RXs through the assembly line to reap more return for the same fixed capital investment.

shawnst

Thanks Lexmex. Next time I will remember to drain the front differential too.

Lexmex

We must have waited like 20 seconds until that test fluid came out the front differential hole, so I can imagine it must have been to save time.

duane

Lexmex,

I wonder why it took 20 minutes to drain out the differential drain plug location when filled from the auto tranny dipstick tube. How much fluid did you put in, and did it all come back out.

Duane

Lexmex

We must have used about 2 liters of fluid. You probably mean 20 seconds according to my post above. I think that there was a discussion once on this forum about whether the ATF fluid circulates well into the front differential area. We weren't exactly sure how much came back out. However, I remember we also did pull the tranny plug afterwards and just a trickle came out, maybe .1 to .2 liters.

atag

So can you just drain them both at the same time just pull both plugs? And then fill with 4.5 bottles of Toyota Type-IV is that the just of it? And it gets fill through the dipstick hole
?