Could low LSD fluid set off a check engine light? I ask becasue mine has been on for a week or two now and I haven't had trouble driving or wheeling...nothing seems different but I noticed today that there is a wet spot (not drippingj ust moist) on the bottom plug of my differential. I just had it serviced a few months ago. Maybe this is the cause?

Having appearance of leaking is common. Well at least most of the truck I have seen have a little spot on the diff near the plug. Why don't you go have the codes pulled at Auto Zone and then search them instead of stressing yourself over the guessing game because it really could be alot of different things, that set off a code.

No, low gear oil will not trigger a check engine light.

Have you checked to see that it's not engine or tranny oil that sprayed back to the diff and is wet when you stop? For sure it's gear oil and not something else?

Just a thought, because if your engine oil dropped, that might trigger a light.

Low engine oil will not trigger the 'check engine' light. Also if you pull the codes from Auto Zone you don't have to search for them, they can tall you what the code means in the store. Saves a little more time there. I just had that done a few weeks ago on my dad's Maxima.

The codes are related to emissions equipment and all the various sensors from the charcoal canister to the O2 sensor and everything in between.

Low oil, broken motor mounts, wheels falling off, and throwing a rod won't cause that light to come on.

so what do i do? i go to auto zone and just say scan my truck? how much does this cost? sorry i am new to this

Go to Auto Zone and ask them to run an engine diagnostics on your truck. The best part is that it's a freebie! They can also look up what exactly that code means. Good luck. Even if you don't know when the explanation means you can always search it online when you get home or ask here!

AAhh I see it now...Thanks a lot for your help guys...better than bringing it to the stealership.