A few months back I started to notice a bad smell coming into my cab - smells like synthetic gear oil or something. It happened only when I got into my truck after I had it up to temp, then shut it off, hooked up my trailer, then got back in...there was the smell.

Now it has become a lot worse. When the engine gets up to temp and I stop at any intersection I smell it. Even when going down the highway now it is faintly there.

Today when changing the engine oil, the smell is even in the engine bay. But no leaks that I can see.

I'm taking it into a Dodge dealership tomorrow as I can't stand it any longer and it's getting too cold to roll down the windows. Any thoughts?

 

I'm an idiot. My post should have been in the 5.9 forum. Sorry.

 

If you are using Rotella, it will smell like that for a couple hundred miles every time you change oil until the additives burn off. I use Delo and no more stink.

 

I agree with Lary. I use Rotella and I get the "smell" just about everytime I change the oil for a couple of hundred miles or so. Doesn't bother me though. If fact, I kinda like it.


If you didn't use Rotella....maybe it is the brand of oil you are using.

..

 

No Rotella (I use Royal Purple). And it got worse & worse over a few THOUSAND miles. Just change the oil yesterday and it didn't get better or change.

It's not a faint smell either, it's strong enough that one thinks they're getting gassed in the cab...I'm the son of a heavy duty mechanic and like the industrial smells of diesel...but this not a good smell and is WAY too strong now.

 

Check the front diff it see if it leaking at the pinion seal.

 

Manual or automatic? If manual check for a torn shifter boot on the transmission.

MikeyB

 

If you have a 6 speed, the shifter boot may be split (common), but you list a "mag-tech" tranny pan so I'm guessing an auto?

Maybe you can get the truck in a slight breeze and by turning it and sniffing around you could narrow down where it is coming from. If it's that strong you should be able to track it. Get your wife to help, mine's got a nose like a blood hound .

Good luck

 

If it's gear oil, you'll know it. Way more pungent than ATF or engine oil.
Only do it after you run/tow hard with the truck? Had an 01 that the rear axle would get so hot towing that it would burn the gear oil and melt the speedo sensor off the top of the pumpkin. Went thru 3 complete axle replacements, bad setups I guess. Cehck how hot your rear diff is when it smells bad.

 

If your smelling it in the cab while going down the road I would think you could focus your search from the T-Case forward. Like billie said, enlist the help of a woman, I had a girlfriend once that had such a powerful sniffer that...oh never mind, you get the drift!

 

I have a 2005 2500 Dodge that has the same problem. I was just trying to find something like it on the net. Mine started smelling like diesel a couple months ago. Although at the beginning I didn't really think it was diesel. It smelled less pungent. However, now it is getting much worse. I don't really smell it while I'm driving. After I park it, get out, and return in a few minutes it wreaks. It smells horrible after being parked in my garage over night. I must roll down the windows now every time I get in. After a couple minutes I can roll them up and I'm fine. I was hoping to have something to tell the mechanics before I put it into the shop.

 

If you have a diesel smell after you part it check your CP3 for weaping diesel out the bottom. That is a common problem.

 

Boiling batteries? Not really a gear oil smell but it can be bad.

 

Just added two new batteries four months ago. My son just came into town and said it smells like transmission fluid or gear oil? He's pretty sure that its transmission oil.

Any idea how that would come into the cab when it stops running?

 

(The truck is automatic)

Found out it was the front diff with a leak and expired oil. I used Amsoil and thought it would last longer than it did...especially since I hardly use 4x4.

I was told that there is a pickup hose nearby the front diff that if there are any fumes, they get aspirated into the heating system of the cab interior. Odd design.

And my pinion seal was going too leaking oil as there was a slight bend in the joint.

"OOPS" ... looks like you had the best guess!