New here, Hello all. I have a 2015 IS250 Base, AWD. Trans/driveline code is GSE35L, I think. That is the code on the car info sticker and I see parts places asking about this code but not certain what GSE35L means exactly.

I have searched these forums for a couple of hours and I see threads that go on for years debating differential fluid change intervals, I'm not jumping in to those. What I haven't found is can I use the same fluid in the front and rear diff? The manual says:
Front: hypoid gear oil API GL-5 SAE90
Rear: Toyota differential gear oil LT 75W-85 GL-5 or equivalent

I find rear diff oil is Toyota p/n 08885-02506. I haven't yet found the Toyota p/n for the front diff oil.

It seems like the difference isn't significant. Both GL-5 and both about the same weight. Can I buy 3 quarts of Genuine Toyota diff gear oil LT 75W-85 and use that front and rear? Or a Redline/Amsoil or other fully synthetic 75W-85 or 75W-90 in both?

I guess I am confused by the differences in the manual. The front specifies "hypoid gear oil" but gear oil is agnostic about the gears it might get used on. Not to mention there are hypoid gears front and back. Also the rear specifies GL-5 while the front specifies API GL-5. The API is the source of the GL-5 category so isn't "GL-5" exactly the same as "API GL-5"? Sorry for nitpicking, I'm just trying to understand.

 

There were videos describing how to change diff fluids. I believe it is the same AWD system on the GS as on the IS.

 

Liquimoly says they’re the same but different weight.

Ravenol says they are different. I believe this option is in agreement with the manual.

I personally went with the Ravenol EPX 80w-90 yellow bottle of gear oil for front and the gold MTF-1 75w-85 for rear. My 2018 AWD has been running just fine. I think I have put 60k+ miles on the new fluids off the top of my head. I drive the car year round with full winter tire setup when necessary.

I addressed it here in post #9 some time ago.

There’s also this over on BITOG (though this might just confuse you more lol).

Hope this helps.

 

Thanks, good info. I ended up buying the Toyota branded oil. Called a couple of dealers and checked online prices and bought it from a Toyota dealer nearby for under $30/qt. Still expensive but about half of the lowest cost I could find from a Lexus dealer.

The rear 75W-85 from Toyota is synthetic while the 90W front diff oil is not, according to the guy at the parts counter. Good to see the Ravenol site agrees.

Toyota p/n 08885-02506 has been superseded by 08885-02906, both p/n are for the rear 75W-85.

 

Probably the smart choice. Why risk it?

 

Just realized I wanted to add to this for anyone doing this in the future. I used Toyota synthetic 75W-85 p/n 08885-02906 in the rear diff and LiquiMoly Hypoid Gear Oil (GL5) SAE 85W-90 in the front diff.

With nearly 120k miles on the car the rear diff oil came out looking almost as clean as the new stuff I put in.

The worst part of the job was trying to get the front fill plug back in. My hands are not the right size to position it and there is zero room to get a socket on that plug just to guide it to the correct place.

Pretty sure I am the first to replace the diff oil because we have owned the car since it had 50k miles on it. Front diff drain plug had a copper sealing washer, fill plug had a crush washer. Rear diff fill plug had a crush washer. Rear diff drain plug did not have a washer. Weird that 3 out of 4 plugs would have a seal and the 4th would not.

 

Diff oil is something that should be changed at least once. The first time it will come out dark or with lots of shavings on the magnet plug. After that it should be pretty clean unless there is an issue.

 

Did you have to do anything special to get to the drain bolt I could not get a 14mm on it without it wanting to round off.

 

The front diff fill plug is on tight. The video linked above in this thread is for a GS350 but the differentials are the same, I think. He used the old fashioned impact wrench, put a 14mm wrench on the plug and tap it with a hammer over and over. I used a long wrench and torqued back and forth until it broke free. A lot of torque to loosen, then a little in the other direction to tighten, then a lot to loosen, repeat until it breaks open. Use a box wrench for sure, not an open ended wrench. If you are worried about rounding it maybe buy or borrow a 6 point wrench? Good luck!

 

Thank you I appreciate it, was it hard to get the fill plug back in because of the limited space?

 

It was hard to get the fill plug back in because:
-I was on my back in the driveway not in a garage
-I had the front end on jack stands so not a lot of vertical space to maneuver my arms
-one of the jack stands was on the suspension mount nearby so in my way
-there is something, I think steering related but I did not investigate fully, half an inch behind the plug so no way to get a socket near there or to get fat fingers in there
-putting the plug at the tips of my index and forefingers I could just get it into position but couldn't then turn it
-with my hand crammed into the limited space to get the plug in place I could no longer see it so the operation was done blindly

What ended up being successful for me was balancing the plug at the tip top of the fingers on my right hand and raising it up to get it to the right height, then snake left arm up over axle and through maze of steering, exhaust, suspension, wiring etc and use left hand to twist it. All blindly so it took several attempts before it lined up correctly and caught the threads. As soon as the threads catch it is easy peasy.

 

i just did mine today, the front transfer case drain bolt and the fill bolt were the worst, my drain one was on the verge of rounding off.
but with enough force and leverage and making sure it wasnt angled in anyway, it cracked loose

 

What year Is do you have?

 

2015 IS250 AWD base model