Diff and Transfer Case oil change at 40-45k?

JLM3rd said:
Hi All,
When I was last at my dealer for the 40k mile service, the service writer recommended changing the front and rear differential, and transfer case oil.
I declined, but I expect it'll come up at my next visit her shortly.

I do a lot of highway driving (>75%), and rarely use 4WD. Is this a service worth doing, for longevity, or is it just plus-selling by the dealer? I've no objection to getting it done, if it will truly help maintain the vehicle.

Thanks
John
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I'd highly recommend it. I changed mine at 5k miles and the rear diff was pretty dark and the plug was pretty caked with shavings already (not totally uncommon though from initial break in). I plan to change the diffs every 15k. The transfer case oil was clean, probably do that every 30k.

You can buy a seal kit off amazon that comes with all the washers you need for like $10. You'll need a hand pump from the Auto Parts store but that's about it other than wrenches / sockets. It's not a difficult job, I wouldn't pay anyone to do it for you. If you can change your engine oil, you can change your diff fluid.


I went with Amsoil Severe Gear, highly recommend that fluid. It tends to outperform most everything on the market in oil tests I've read.
 
Nastyman said:
I recommend checking the differentials and transfer case at least once, even if you don't drain/refill.

I purchased a 2016 Limited 4R in January of 2017 with 2 miles on odometer. Checked the "hard to get to" fluids at 500 miles. Both differentials were low (i.e., couldn't touch fluid through fill hole for either differential). Needed 3/4 qt to fill rear and 1/4 qt for the front to raise levels to bottom of fill holes. Transmission and transfer case were okay, though.

FWIW, my 2016 Taco was 3/4 qt low on transmission fluid. Beginning to make me wonder about Toyota quality control.
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My guess is Toyota does this on purpose to account for heat expansion and to save money by not adding unnecessary oil to each car they make. Spec is within 5mm of the fill hole. You can bet Toyota knows exactly how much oil to add in the factory to be 5mm below that fill hole.

Servicing is different because no tech or person is going to worry about trying to get the oil level 5mm below the fill hole. The FSM even states to fill it until oil run out of the fill hole. But the actual spec is 5mm below or higher up to the fill hole. The 5mm below the fill hole amount of oil is easily controlled in the factory during assembly.
 
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Kenstaroni said:
I'd highly recommend it. I changed mine at 5k miles and the rear diff was pretty dark and the plug was pretty caked with shavings already (not totally uncommon though from initial break in). I plan to change the diffs every 15k. The transfer case oil was clean, probably do that every 30k.

You can buy a seal kit off amazon that comes with all the washers you need for like $10. You'll need a hand pump from the Auto Parts store but that's about it other than wrenches / sockets. It's not a difficult job, I wouldn't pay anyone to do it for you. If you can change your engine oil, you can change your diff fluid.


I went with Amsoil Severe Gear, highly recommend that fluid. It tends to outperform most everything on the market in oil tests I've read.
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15K is overkill isnt it? Unless you're constantly towing and 4 wheeling I'd do it every 50K for the rear diff and 100K for the front. Amsoil severe gear is supposed to last a very long time. I bet you could bottle up your 15K severe gear fluid and resell it.

https://www.amsoil.com/shop/by-product/gear-lube/severe-gear-75w-90/

check out their interval guide on the website.
 
WallyT4R said:
My guess is Toyota does this on purpose to account for heat expansion and to save money by not adding unnecessary oil to each car they make. Spec is within 5mm of the fill hole. You can bet Toyota knows exactly how much oil to add in the factory to be 5mm below that fill hole.

Servicing is different because no tech or person is going to worry about trying to get the oil level 5mm below the fill hole. The FSM even states to fill it until oil run out of the fill hole. But the actual spec is 5mm below or higher up to the fill hole. The 5mm below the fill hole amount of oil is easily controlled in the factory during assembly.
Click to expand...

Not trying to argue the point, but both differentials in my 4R were underfilled below the 5mm spec (which is less than 1/4", by the way). Stuck my pinky into the differential to the second knuckle and bent it, which is maybe 3/4" to 1" below the bottom edge of the hole, never touching gear oil. So....not even close to minimum spec.

I might agree with your point about Toyota using minimum fill levels to save money, but that isn't consistent with what I observed on my 2016 Taco differentials, which were filled correctly. Also, while my Taco was at a minimal to low fill for the AT fluid and I didn't personally have any problems, the low-fill AT issue was a problem reported by many other 2016+ Taco owners who actually had transmission problems as a result. Appears to be a quality control issue to me.

FWIW, I only submitted my original post so folks are aware that at least one person has experienced what appears to be low fluid fills on two brand new Toyota vehicles.
 
the oil level on diff will be below the fill hole slightly if the oil is cold. the gear oil does expand quite a bit.. if the diff oil is replaced when cold it may pour out if you drive it a few miles to then check the level.

also IMO DIY do not set vehicle exactly level so if the front end is slightly lower than rear that will do it ..

when pumping the oil in the diff air bubbles will be created .. so when the air releases then the oil level will drop.

if its cold and 1/2 inch below the fill hole using a plastic tyrap/strap then its good. but the vehicle must be level for accurate check .. same deal on the tranny check ..I put a level on tranny pan set vehicle level then check it @105-110F..
 
Finding the gear oils

I posted this in a similar thread on Friday. The info may help those of you trying to find the right gear oils.

The gear oils are hard to find locally. I tried to find the right gear oils in auto parts stores here yesterday. The only thing I found were quart bottles of Mobil 1 75W-90 gear oil in quart bottles for around $12 each. I found the new canister style oil filter to fit the Baxter Performance inverted remote oil filter adapter, the Mobil 1, M1-209. I didn't find any 75W for the transfer case, in store or on Amazon, except for the Toyota brand which appears to be made by Exxon Mobil.

I read the Mobil website on gear oils and looked for the local distributor. I found two distributors, both in the Long Beach area, 40 miles from here and hard to reach with LA traffic.

So I'm ordering everything on line from Amazon: 1 Liter of the Toyota 75W transfer case gear oil (~$32) and the 2 gallons of Mobil 1 LT 75W-90 Delvac Synthetic gear oil for the differentials.

I'll gather all the oils and parts and then let my local neighborhood mechanic do the work. I need his invoice to keep my drive train warranty current, I need a place to dump the used oil and I need to patronize the shop where I'll go for repairs I can't do or don't have time to do myself.

How do you guys verify your service maintenance for warranty if you do the work yourselves?

Juan's Automotive on Allen in Pasadena is a good shop. He really liked my ICON lift and he's been repairing my '95 Jeep GC for a few years already. I got a lot of street cred' with him for doing the install myself.
 
Just another vote for using the Toyota 75w transfer gear oil in the T case. I ponied up the money for the “authentic”fluid and just did the change. It is much different than the 75w-90 used in the diffs. Don’t skimp. Use the right fluid!

I also did it at 50k and it looked “pretty good”. That is ridiculously unscientific I know but I bet the transfer case could be changed at a 100k interval?

I am doing it every 50k however.
 
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