Just bought a 2007 RX350 and am wondering how and when transfer case oil should be changed.

 

Use the search function there's a lot of great posts about it here, same procedure as the 2004-2013 Highlander as well on Toyota Nation if you need more info

 

It seems hard to find the post about it so I'm going to post it here:



Tools: 24mm wrench, 3/8" flex head ratchet w/ 3/8" to 1/2" adapter w/ 1/2" 24mm socket and 18" 1/2" breaker bar



The t-case takes 1L (1 jug) of 85W-90 GL5 gear oil from the factory. I just used synthetic 75W-90 on mine as 85-90 is harder to find. You will need a pump to pump the oil into the t-case. Fill until it starts pouring out.


I used the breaker bar to get the fill plug loose first, you won't have a lot of room w/ the exhaust pipe in the way so a compact breaker bar like this will fit, a ratchet will not as it's too bulky. The 24mm closed end side is used to break open the drain plug. Make sure to apply a lot of pressure and hold down so it doesn't strip or fall off. When refilling, the 3/8" ratchet comes in handy to tighten the fill plug back in as it is very tight. I used the wrench again to get the drain plug tight. The plugs are torqued to 36 ft lbs and you need two drain plug washers to replace them. I have done this on 3 separate RX350s (my 08 and two 07s) and it has worked flawlessly each time.


Washers: 90430-18008 x2

 

There's several YouTube videos on how it's done, extremely simple/straightforward.

When? If you don't have a history on when it was done then the answer is "immediately" along with the rear diff, engine oil, coolant (carefully inspect the radiator at that time), and brake fluid. As a interval change, I'll do mine every 50k miles as again it is cheap and very easy. Bought my RX a year ago as a habit whenever I get a new-to-me car I always change all fluids so I know it's been done and with what fluid

 

^ This - definitely just do all fluids on any new car you purchase ^


When I first got mine, the t-case was half full and the oil was like a black sludge. The previous owner got the driveshaft changed and the ding dongs that replaced the shaft didn't even top up the t-case let alone drain & fill, factory fluid at 215k. It's a testament to how durable these things are

 

A close lady friend trusted Jiffy Lube on changing the oil in her cvt Nissan, a few months later it blew as that trans requires very specific fluid. She was told it is better than OEM. NEVER trust any shop or previous owner... like Matt experienced, I've seen many times even from dealerships... you don't know what is in there, how much is in there, when it was last changed unless you do it even if you're handed a receipt for work done.

For doing this fluid change I bought and used a 24mm crows foot wrench bought on eBay think it cost me $7 made life much easier highly suggest it I couldn't get a wrench or socket in there. For fluid I used Mobil 1 synthetic

 

Since your changing the PTU/transfer case oil, great time to change the rear end fluid as well as the transmission filter/fluid too. I used 2 qtrs of 75/90 Royal Purple gear oil, a gallon of Max-life trans fluid w/ a Wix trans filter. Great time to clean the two trans pan magnets. Before you drain the fluid make sure to undo the fill plugs first.......

 

Didn't quite have a couple of tools per @MattRX post #3

• 3/8x1/2 adapter isn't common
• 24mm wrench isn't common. Luckily neighbor had a cheap one
• Had a 24mm 1/2 socket in my 2nd toolkit (non in my main kit) 24mm 3/8 socket (also isn't common, my main kit ended at 22mm) would have been better as I had more 3/8 extensions and 3/8s are smaller and more maneuverable in this tight space in general.

Removal

• box end of 24mm wrench wouldn't fit on the drain plug. Transfer case require fairly thin walled. So used the open end carefully (one hand holding open end steady on the plug) and broke loose without too much force. Maybe last change didn't tighten 35ft/lb. Anyway, it's a big wrench with lots of leverage.
• breaker bar + 24 1/2 socket broke loose fill plug easily.

Install

• 950mL Synth GL5 75/90
• open end 24mm wrench on drain plug. Guesstimate 35ft/lb
• Didn't have a 3/8x1/2 adapter (1/2x3/8 is quite common) Was able to rig up 24mm 1/2 socket to universal to short extension to 1/2 torque wrench and tighten. Need to adjust and position the u-joint on the universal to to avoid binding up on surrounding structure.

Other likely helpful tools

• A long 1/2 extension would have helped torque wrench to reach from behind the cross member

Certainly tight quarters between

• transfer case's long nose towards the prop shaft
• exhaust pipe
• subframe cross member

Have to get the just the right combo of tools in the right orientation to get this




Potential Leak

~7/10L drained out for me so either it was previously slightly underfilled or maybe its the leak under the transmission transfer case mating seam

Breather

Tucked in between transfer case and rear bank of the engine. Impossible to each from bottom. Maybe from top when rear bank is more exposed? I guess most people don't change this due to access difficulty? haha

 

Nice job! I need to do mine again as it has been 4 yrs and I should have flushed out that fluid earlier as the first drain and fill was the first in its life... At 225k miles and it was NASTY! The fluid was like tar

 

>>>Thanx to the PO not doing the basic mantence, as most ppl have no clue. I've replaced a few pto's in varies ford's. The pto only holds a qtr & needs to be changed. At least on the '13+ sho taurus w/ the performance package comes w/ a pto cooler which helps, cooling & additional volume.

 

Is this a self-contained unit on the t-case itself, or is it a separate cooler? That's pretty neat, I've never heard of a diff / t-case using a cooler outside of racing applications. I'm guessing the Fords are likely using some kind of thinner, trans fluid maybe? Some of these Mercedes t-cases I've done the fluid on use thin fluid like Dexron 6