[newhl2016]

Hi, I am purchasing a 2009 Highlander Limited AWD tomorrow. Had it checked today and the mechanic said fluid was leaking from the transfer case vent hole. I've read the tsb for this and understand it is likely a $2k repair. However, my question is: must it be repaired or can it be left alone? If left alone, what are the risks and how would I manage them? It has 138k miles. Thanks.

 

[sweeneyp]

So I just looked at that TSB (its T-SB-0138-10 for anyone interested), it looks like the cause is the inner bearing seal on the passenger side output letting fluid past into the pressure relief cavity between bearings. If its not a fast leak, and you stay on top of fluid level within the transfer case, I don't see anything major that could happen. There is nothing fancy going on in that transfer case, its simply a spool and ring/pinion gearset. If it has enough oil, it'll be fine. Let it run dry and it could chew itself up though. If its anything like my old Jeep was, you'll hear the gears whine if they don't have enough oil (don't make that be your indicator to fill it). I'd say talk to the mechanic to get his opinion on how fast of a leak it is.

 

[Greasymechtech]

It can't be left alone, unless you're a suicidal gambler. The ATF leaking into the transfer case is a tickingtimebomb.

It must be dealt with now, if you don't want it seizing while you're driving. When it fails, it will lock up. You will have the front/rear wheels locking up, as you skid uncontrollably to a stop.

ATF does not have the EP additives or viscosity film thickness that a GL5 gearbox requires. ATF's AW additives and low viscosity will thin the gear oil out. Eventually, that lack of proper lubrication will cause the transfer case to fail.

Bandaid for temporary relief.... flush the ATF completely with a good ATF. Valvoline Maxlife, Lubegard, or Redline D4/D6 are a few to consider since one has extra seal conditioners and the others have a little more ester base oil which is also a good seal conditioner. And, add a bottle of Lucas trans fix to the current fluid NOW, add a measured dose to any ATF that you choose to use.

http://lucasoil.com/products/problem-solvers-utility/lucas-transmission-fix

http://www.valvoline.com/our-products/automatic-transmission-products/maxlife-dex-merc-atf

http://www.redlineoil.com/product.aspx?pid=115&pcid=9

http://www.redlineoil.com/product.aspx?pid=51&pcid=9

http://www.lubegard.com/~/C-1036/COMPLETE+Full+Synthetic+ATF

Since the transfer case calls for 85w90 or pretty much any 90 grade GL5 gear oil, and you have ATF diluting it constantly, simply change it out more often and use a 140 grade gear oil. If you use a 75w140, 80w140, or 85w140, you'll have the bandaid of viscosity to temporarily prevent catastrophic transfer case failure, until you can fix it. Change the gear oil IMMEDIATELY. I would change it 'quarterly' with Used Oil Analysis to determine how quickly it is being diluted. A UOA could give a little peace of mind and allow you to run the 140 grade gear oil for a longer interval. Once you collect a few transfer case gear oil UOAs, at 1 month of usage, and again at 3 months, you can determine the extent of the ATF leak gear oil dilution. A gallon of 140-grade gear oil at your local store is <$20 and good for at least 3 transfer case drain/refills.

Labor is the issue since if you can't DIY, you'll have to source the fluids and drain plug o-ring gaskets, pay the local shop for each drain/refill, transfer case sample collection, the ATF flush.... which can quickly add up to the $3k proper fix.

 

[sweeneyp]

How on earth did atf leaking into the transfer case come up??? The seal that is bad is on the opposite side of the transfer case......it has zero contact with atf.....

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[Greasymechtech]

... the mechanic said fluid was leaking from the transfer case vent hole....

ATF leaks into transfer case. Transfer case vent pukes it out.

Hows does fluid leak out of the vent? When it is overfilled or something(which is ATF) is displacing it.

It is a KNOWN issue with Toyota Rav4, RX, Highlander, Sienna.... AWD vehicles.

DO NOT BUY THIS VEHICLE UNLESS IT IS REPAIRED 1st! You do NOT know how long its leaking. And, you do NOT know if it will fail tomorrow, in 30 days, or whenever. But, if ATF is in the transfer case, it WILL fail, usually unexpectedly.

 

[sweeneyp]

You realize we are talking about the right side (opposite side from transmission) bearing housing pressure releif vent right? Its essentially a weep hole just like you see on a water pump, literally the same thing. We aren't talking about the main pressure vent for the case cavity itself... Its coming out because the inner seal (before the vent, the part redesigned that the whole TSB is about...) is leaking due to bad design...not displacement :facepalm:

 

[Greasymechtech]

T-SB-0335-08

Some customers may complain about a red fluid leaking from the transfer case vent on top of the transfer case or between the transfer case and transaxle. The root cause of this issue is related to damage to an O-ring during the transfer case assembly process allowing automatic transmission fluid (ATF) to enter the transfer case during vehicle operation. Production countermeasures have been implemented at the transfer case supplier. Replacement of the transfer case assembly will be required to repair the vehicle.

 

[sweeneyp]

Oh I wasn't aware there was a second vent leak TSB for the transfer case (solid Toyota...), my bad. I was reading the other one wondering what on earth you were going on about :lol:

Guess it comes down to which one was leaking, OP's post is kinda vague

 

[newhl2016]

Thanks all for the great information. I only had a day to consider this before buying the car so did not get to read your posts before buying it. I am pretty good with cars and always do the easy stuff, like timing belts and brakes, myself, but trannys and transfer cases are way over my head (other than having replaced a few pressure switches - again very easy). Anyway, I got the car for $15k OTD - a very good price for my area. It is a black Limited with gray leather/Navi and looks great. It has 138k miles and was serviced by Toyota literally every 3k miles and is up-to-date on the maintenance. The transfer case fluid was flushed/changed almost a year ago at 121k so I guess I'll have that done again along with the tranny fluid - it's a little dark. Wondering if I should do them myself.

I have a 1999 Solara V6 that is still running strong at 212k miles and with the HL being so well built (except for that $20 o-ring), I am guessing it has at least another 5-10 years left in it. The last 3 family cars have been Honda V6's, and we also have a 2009 Acura now that is not doing very well, so wanted to go back to Toyota. Anyway, all-in-all, I'm happy with the purchase and if I have to drop another few thousand on a new transfer case, then so be it. My oldest son just graduated college and took our 2005 Pilot and my other 2 are in high school and needed a safe car they can drive now and then take to college in a few years. I put all new brake pads on the other night, just ordered the draw-tite hitch and am trying to figure out how to get the XM working and we're good to go. Thanks again for the in-depth replies.

 

[DJSteve]

If you search my posts you can read a full account of my experience fixing my 06... I also put together a blog write up with some pictures and tips that you can find at http://www.stevesalt.com/toyota-0138-10-tsb-transfer-case-inner-seal-highlander-sienna-rav4-2/

sweeneyp, I'm not sure if I misunderstood your comments about leaking ATF, but there *is* normally ATF in the outer portion of that bearing carrier. There's an ATF passage through the top of the transfer case that connects that outer cavity to the transmission. The part that fails is actually two seals back to back, which are centered over the other end of that weep hole in the bearing carrier housing.
Gear Oil/Transfer case - Seal1 - weep - Seal2 - ATF/outer bearing carrier cavity

If Seal1 fails, gear oil comes out the weep hole.
If Seal2 fails, ATF comes out the weep hole.
And presumably if there is more pressure on one side or the other than can be relieved through the weep hole--or both seals are compromised--you end up with fluid mixing

 

[sweeneyp]

Interesting, I wouldn't have noticed that little o-ring above the input on the transmission mounting side unless you said that... Are you talking about the weep hole on the transmission side or the passenger side?

 

[DJSteve]

I'm talking passenger side of the transfer case.

There is a small o-ring between the transmission and transfer case for the ATF passage as you mention, and and another one between the bearing carrier and transfer case body (see figure 15 on pg 13 of the TSB).

There is a ball bearing in the outer end of the bearing carrier assembly that supports the RH axle, and that bearing runs in ATF. This is shown in Figure 6 of the TSB--behind the axle seal (it's in the diagram even though the instructions never mention removing it). In addition to the ATF passage through the transfer case, I think ATF can also pass through the center of the ring gear carrier.

Sort of hokey, but I'm guessing there was no good way to seal around the RH axle at the transaxle-transfer case interface.

 

[dcm0123]

Are these that complex a mechanical can not open it up and replace an O-ring?
Resealed a Volvo transfer case recently which was very simple inside. Unfortunately the Volvo units have issues with coupling wear.

 

[sweeneyp]

Didn't even think about the inner axle not being sealed at the transaxle/tcase joint , now it makes a lot more sense having fluid at the opposite side.

Dcm, as far as spool transfer cases go, it's pretty straight forward. You wont find anything crazy you won't find in a differential rebuild. It's just access to the tcase itself is not what you'd call easy

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[MileHighlander]

Well I went in for an oil change at the dealer last week and they noticed the leak, said it was the TSB 0138-10 leak at the Transfer Case. My extended warranty thru MaxCare / CNA (CarMax) covered all but my $50 deductible. They dealer even covered the $90 synthetic oil change for no charge since this was a big repair. 15.5 hours of Labor



Running total on my extended warranty payouts, still have 2 more years or up to 150K miles:

Water Pump: $700
Intermediate Steering Shaft: $250
Replaced Drivers Seat due to heater not working: $400
Transfer Case leak TSB 0138: $2.8K
= $4150

 

[twinster2]

Anyway, I got the car for $15k OTD - a very good price for my area. It is a black Limited with gray leather/Navi and looks great. It has 138k miles and was serviced by Toyota literally every 3k miles and is up-to-date on the maintenance.

Maybe its me but that seems kinda high for a 8 year old Highlander with 138,000 miles on it. Where do you live?