vu0219

Hello all,

I recently acquired a 2003 RX300 AWD with 110k miles. Everything seems fine except the transmission oil level even when cool is roughly 1.5-2" above the hot mark on the dipstick.

I want to drain some of the excess oil out and at the same time change the filter, drop the pan, also the transfer case as well.

What would be the proper way to do? How much oil should I pour back in? Can I pour like 1-2 quarts, then start engine, wait a little, row through gears, then check the fluid level, then add more if need?

Will I damage the transmission if I do not have enough oil in the oil pan?

Also, please correct me if I am wrong. Transmission and transfer case both use ATF (OEM T-IV, Mobile ATF 3309, Amsoil) while front and rear differential use gear oil like Royal Purple 75W90 Synthetic Gear Oil.

Thank you for your help.

Lexmex

Welcome to the Club.

Good questions.

I am quite notorious for overfilling my tranny and I regularly go to the IV point (on Type IV) on my dipstick without issue.

There is a thread at the top of the RX300 forum done by TunedRX300 that describes changing out the tranny fluid. He has an AWD just like you and me.

What happens if you don't have enough tranny fluid (I know this from recent experience, within the last 2 months, after working on my tranny) that if you are short say 2 quarts or so you will feel a surging sensation in your shifts and the shifts will be hard jerks. It was then that my uncle and I knew that before we took her around the block again to give it 2 more quarts. You won't damage the tranny just taking it around the block to check it out, but just follow TunedRX300's steps to the letter and if you still aren't sure, just ask.

On the gear oil, if you are talking about the transfer case that has a driveshaft leading to the rear differential, yes both of those take 75W90 gear oil like Royal Purple (I use that). Each one hold .9 L of gear oil.

However, there are two drain plugs on the tranny, one that I like to call the front differential (see below in the photo on the left) and the transmission pan plug on the right. Both of these have ATF in them and both are filled via the tranny dipstick (the ATF will trickle over to the front differential).

salimshah

If you plan to drop the pan, you might as well drain the pan. I do not recommend re-using the oil.

You can suck out the fluid through the fill and check point (dip stick).

Please read the thread on Not getting a good read on transmission fluid level.

Salim

vu0219

Thank you Lexmex and Salimshah for the reply.

Another question. How come the front differential uses AFT fluid while rear differential uses gear fluid.

Is it because the front differential in the same unit of the transmission? But then if the front differential can use AFT fluid, how come the rear one must be filled with gear fulid? In theory, differential is differential.

Lexmex

Yes, it is part of the same unit.

Let me show you so you can get an easier grasp of this.

Blue is the tranny drain plug, holds ATF
Yellow is the front differential (part of the transmission) and hold ATF.

Red is the transfer case and that holds grear fluid and there is a shaft extending to the rear differential (next photo coming up) that also hold gear fluid). The transfer case and rear differential only exist on AWD vehicles.

Lexmex

And here is the shaft leading to the rear differential.

vu0219

Thanks Lexmex, awesome pictures