Gear Oil Smell in Cabin (1 Viewer)

[ATXGX470]

Gents,

I'm a new owner of a 2008 GX470. It's a very clean truck for the most part with an extensive service history. Currently it has 120K on the odometer.

As part of my ownership process I typically change all fluids. This always serves as a great way to get to know the vehicle and serve as a starting point to record my own maintenance intervals.

I decided to drain the front and rear diffs along with the transfer case. Filled them all up with Redline 75W90 gear oil.

The transfer case and rear diff were clean. The front diff was a little dirty.

What I'm noticing now is that when the HVAC is running on Auto setting and it's pulling fresh air from outside I get a faint gear oil smell in the cabin after stopping the vehicle. The smell last for a few seconds and then seems to dissipate. It can also happen intermittently. The one consistent time I will get the smell is if I exit the highway and stop at a stop light. My workaround has been to press the recirculate button as I approach the stop. Then there is no smell.

I don't think that I overfilled the diffs or transfer case.

Anyone have a clue as to what could be causing this? It was not happening before the gear oil drain/fill, so I'm scratching my head a bit.

Thanks for any info - !

 

[ATXGX470]

The stock differential breather should have a rubber hose leading from the differential to the cowl area under the hood. The hose is then terminated with the breather plug, which acts as a check valve to prevent water/debris from entering the hose leading to the differential. You should be able to remove the stock breather plug from the underhood hose and replace it with a new Doorman (or OEM Toyota) plug.

Awesome - plug(s) ordered from Amazon. Should be able to wrench this weekend, so I’ll report back.

Thanks for the info guys.

 

[Bigtime]

Interested to hear any remedies with this issue. I have the exact same problem and have been pouring over all possible sources. I did notice that the smell was reduced after changing the fluid in the front/rear diffs and T-case.

I'm going to look at the top of the transfer case when I install the Grom Vline 2 this weekend and see if the shifter has a seal that is allowing fluid to leak through the top.

 

[ATXGX470]

Interested to hear any remedies with this issue. I have the exact same problem and have been pouring over all possible sources. I did notice that the smell was reduced after changing the fluid in the front/rear diffs and T-case.

I'm going to look at the top of the transfer case when I install the Grom Vline 2 this weekend and see if the shifter has a seal that is allowing fluid to leak through the top

OK - I replaced the OEM front diff breather plug with the Dorman plug listed above. Very easy to do - took about a minute to install once I located the plug.

It seems to have made a difference for the better- but I still get an occasional faint smell of gear oil when I come to a stop after driving on the freeway.

I’ve used Redline fluid - and I’m wondering now if I should switch back to Toyota OEM?

Will keep everyone posted...

 

[GXO]

I removed the overfull fluid in my diffs and transfer case and it is helping. I need to put some new breathers on when I can get down there, but it is still stinky. I washed the truck with the pressure washer and got into the skids and nooks and crannies as much as I could as well. Haven't really run it much since.

 

[Shoegy]

Hey all, I am having a similar issue to this, I have an ARB rear air locker and just had a bunch of seals and bearings replaced in the back end. Had the landcruiser going down the hwy at about 100km/hr, noticed speed and power dropping to about 80 km/hr. Pulled over and checked under the hood, noticed gear oil around and under the air compressor. Reading on here it looks like an issue with fill volume and maybe a faulty O ring on the compressor. I will get these two items looked at and see if that gets it covered.

I can't think of any other reasons than fill volume as to why oil is coming back up the air lines? Could be a different gear oil was used and is expanding as it heats up? I thought the drop in speed and power was quite peculiar and must be a tell to something more going on here.

Thanks

 

[GXO]

Hey all, I am having a similar issue to this, I have an ARB rear air locker and just had a bunch of seals and bearings replaced in the back end. Had the landcruiser going down the hwy at about 100km/hr, noticed speed and power dropping to about 80 km/hr. Pulled over and checked under the hood, noticed gear oil around and under the air compressor. Reading on here it looks like an issue with fill volume and maybe a faulty O ring on the compressor. I will get these two items looked at and see if that gets it covered.

I can't think of any other reasons than fill volume as to why oil is coming back up the air lines? Could be a different gear oil was used and is expanding as it heats up? I thought the drop in speed and power was quite peculiar and must be a tell to something more going on here.

Thanks

If oil is coming up the air line you have an internal oring seal failure in the diff. If they are new the shop built it wrong.

Update on mine: Redline gear oil and shockproof additive apparently just STINKS for a while. Once I drove the GX for a few hundred highway miles the smell is gone. I think it is just an additive or something that fades with heat and time.

 

[Shoegy]

If oil is coming up the air line you have an internal oring seal failure in the diff. If they are new the shop built it wrong.

Update on mine: Redline gear oil and shockproof additive apparently just STINKS for a while. Once I drove the GX for a few hundred highway miles the smell is gone. I think it is just an additive or something that fades with heat and time.

Awesome, makes sense thank you