Engine oil leak
 

Rebuilt motor new injectors. Now I have little oil stains under the rear if the truck. Anyone know of common sites of leakage. ? Also oil gauge drops to zero sometimes when idling. I have already had to add 3 quarts if oil the past month
Any thought are appreciated
Thank

The factory gauge is a dummy gauge that is controlled by the ECM. If it drops to zero you many not have any thing actually wrong but need to add a real gauge to verify.

Have you crawled under to look around the oil pan and rear seal area? (back of pan)

I have. I was not able to pinpoint the leak. Are there any tricks to pinpointing a leak?

Dye and a black light. And you will most likely find the valve cover gasket leaking at the rear, or your rear main seal is shot. Add the dye, then get under the truck with a black light, while the truck is running, you'll be able to see where the oil is coming from. It could also be the quad ring between the flywheel housing and camshaft, but more likely one of the other two spots.

Good luck