Gear oil smell no leaks

I've owned my truck for 15 years. The previous owner (who had it less than a year from new) was apparently a smoker, and I can still smell it occasionally when it gets

 

I swear it’s just part of life, I dumped my transmission and dif’s a year ago, I occasionally get a wiff of both. Gear oil has heavy odor that clings to everything. Kinda like you can smell a skunk a 1/4 mile away. And if you tracked a molecule of it into the cab.....

 

Yeah, it's amazing how that stuff can just make everything smell. I doubt it's a cracked line, as everything was fine pre-replace and stinks post-replace. And as I said, it only smells under load. i might siphon off just a little from my transfer case and see if that does anything.

 

Well I give up. Just returned from another camping trip. Took the exact same route that I've taken many times before. And now my stink is gone! No trace of it while driving the same roads at the same speeds at the same times of day and during the same times of the year. Go figger...

 

This issue has been ongoing for about a year. Seems like it's gone, then at some random time it comes back really strong. Wouldn't it be convenient to armchair solve it, to say it's just a spill or overfilling or a breather...but no. I'm glad at least there are others with the same issue. It's beyond frustrating after owning my taco for 14 years to have mechanics tell me there is no smell and no problem. I've given up. Buying another truck. If anyone gets to the root of it I'd love to know what you find. I've checked everything for months!

 

i had the saem issue as you i spilled some on the trans case and differential case. the smell is less noticeable now maybe if you clean your casing and differential case the smell would be non existent ive been meaning to clean it just lazy lol.

 

Bringing this back to the top.
I have this same issue in my 04 m/t TRD OR. Maybe it is a torn shift boot. It is exactly as OP described.
Anyone have luck diagnosing it?

 

I have a 2019 Toyota tacoma trd off rd and I changed front and rear diff oil and I have the same smell no leak at all. I can really smell it when I'm going up hills and such. Like it's driving me to string up at this point my breather caps are good move up and down nicely it's like what in gods name is happening

 

Most times it is pushing out the vent then lays on top of the trans or case .

sometimes it pushes out past the shifters .

it does not take much to be able to smell.

 

Yeah I didn't touch my tranny I just did my front Diff and rear Diff that's it

 

Any chance you got some on you and then on the inside of the truck? Only thing I can think of if all you did was the diffs.

 

No couse only time I smell it is when I drive it

 

That's weird. No leaks from the drain/fill plugs since the maintenance?

 

Nope

 

I'd take a look at the front diff breather under the hood.

The actual spec to fill the front diff is like 10mm below the plug, so if you fill it to the plug, it's overfilled.

As the oil heats up it will push out the breather. It'll keep doing that for a while until the oil level is right.

 

Well that explains it. I filled my front diff to the plug hole, not 10mm below. Symptoms same as everyone else. Don’t mind the smell, just glad to know it’s not something actually going wrong.

 

Like others here, every time I change out the tranny oil the smell sticks for weeks, even if I clean it up with acetone where I was working. If you have no leaks and didn't overfill it, give it time, it will fade away.

 

I've had the same experience. I started running Redline MT-90 for the last 200k. the problem was reduced and stunk less.

 

Smells are different I think gear oil smells good.

Then with any scent be exposed long enough you no longer notice.