Oil Leak or Diff leak?

[Kody Budinger]

I noticed some oil on my garage floor and when I got home I looked under the truck and there is oil leaking from somewhere and is on the front of the drive shaft as well as near the left control arm. After searching the board I noticed some similiar leaks but they were diff leaks? Not sure where I should start with trying to find where its all coming from. Advice?

 

[Yardsale]

Crawl under and look.

 

[Gavin Allan]

If you can't find it after crawling under and looking, take it to the self-serve car wash and clean it all real good, then crawl under and look some more.

 

[Ken Hibbs]

maybe pinion seal

 

[Kody Budinger]

I spent half an hour under there when I first noticed it and couldn't anything

 

[Yardsale]

Do as Gavin suggests - clean it good and drive it a couple of days and inspect.



Potential culprits in that area are differential fill plug, pinion, cover, steering system leak, oil pan. Narrow by the type of fluid: if it's low viscosity, probably power steering fluid; if higher, then oil pan or (probably) differential fluid.



There's a lot of turbulence in that area while driving and the leaking fluid can get slung around.



Oh - might be more than one leak, so be observant.

 

[Kody Budinger]

Before seeing your post I narrowed it down to that but the oil seems to be green? Not like coolant green but like a sludge green.

 

[Yardsale]

Green? Green??



Can you post a pic?

 

[Igor Smetaniuk]

This sounds just like what mine is doing. I have the common thermostat housing leak.



You'd be damned to see anything going on around the base of the housing because hard to view with the throttle body and all in the way. The housing leaks coolant and cooks on the engine then leaks down past the water pump toward the bottom of the block. Then while driving the air forces it to spread to the back around the tranny. It has a greenish oily consistency because the engine heat has cooked the water out of it - just leaving the glycol in a thickened state.



Mine has been doing it for a while and I finally got the parts for my extensive list of Spring project repairs.



Also, check your freeze-out plugs for coolant leaks there. If it's greenish colored, you've got to be leaking coolant somewhere.

 

[Kody Budinger]

Its dark green and I've swabbed it and its definitely an oil. Thermostat and housing was replaced about 2 months ago and I checked it its fine.

 

[swshawaii]

If the A/C system has previously been tested for leaks, the dye is green and will be oily. Both tranny cooler fittings on the radiator checked?

 

[EddieS'04]

Green oil??

Even coolant can feel slippery.

Also some of the 4.0L motors can have an oil leak. @ the oil filter mount.

Some of them were porous. You have to pull the exhaust manifold to replace it.

 

[EddieS'04]

whoops double post.

 

[Eric Toften]

Smell it! Oil smells like... oil, sometimes has a slight gasoline or burnt odor. Burnt antifreeze often smells like cookies or syrup. Differential fluid has an unmistakable odor. Pure stink that doesn't go away. Now if we aren't far enough out of the box. Take location into consideration. Left control arm and front of driveshaft aren't common locations to find first signs of leaking systems for any of these systems. But if it's green it isn't differential or oil. Period. What's right above your control arm? Brake fluid and Power steering fluid reservoirs. Both of these can be slightly green. But you would see a leak even a small one very quick in one of these tiny reservoir bottles.