I have a 2006 4 x 4 3500 diesel auto RE . 105,000 miles
Have an oil leak thats never ending. The dealer said it was the oil pan and lifted the motor and installed a new gasket. It still leaked so he pulled the transmission and changed the rear main seal. Again it leaked just as bad.
So they pulled the transmission again and found a small rubber gasket about 2 1/2" above the rear main seal. It still leaked so they did it again with another new gasket and some gasket sealant. It still leaks and it is coming from that same small gasket ???? I'm out $ 4,600.00 and still have the oil leak and of course I know find out they don't have a certified cummins mechanic.
I can't drive my truck ! help

 

A common place is the rocker box gasket, drivers rear corner. Always start at the top of the motor and work down to the oil pan.

 

Finding oil leaks can always be a frustrating exercise. But the the real key is to spend some time in diagnosis prior to spending money on repair. These three methods will usually find the problem.

-- Corn starch. Get the engine hot, and then Clean the entire engine really well with a good degreaser and hot water. Let it sit long enough for it to be completly dry.

Blow corn starch around the engine areas where the leak is most likely. Start at the top and work your way down.

Go for a drive. Where the cor starch is dark is where the oil is leaking.

--- Leak detector kits. Puts a black light dye in the oil.

--- Smoke injector machine. Injcts a petroleum based smoke into the engine, like into the dip stick hole. Where the smoke leaks out is where the oil leaks out. Most shops have one of these.


Diagnose first, then repair.