C8.3 Mechanical - leak under tranny?

[GoWestMan]

Engine Oil is leaking quite a bit from the hole in the bottom of the tranny. Could this be anything other than the rear main seal going?

Also oil gauge is topping out at 80 psi when engine is highway speed. Occasionally drops to 40 psi when idling but sometimes its high even at idle and startup. Is that related and why?


Pic:


https://i.imgur.com/lBeH22t.jpg

[Craig1960]

Sure looks like a rear main seal leak. When cruising my oil pressure is around 80 and 20 after warm at idle. I'm not sure what's normal for these engines but 40 and up at idle when warm sounds a little high to me.

[Ray,IN]

Cummins 8.3 oil pressure,

Lubricating Oil System
Specifications
Oil Pressure
At Low Idle (minimum allowable)........................................ 69 kPa [10 psi]
At Rated Speed (minimum allowable)...............................207 kPa [30 psi]
Regulated Oil Pressure.......................................... ..........517 kPa [75 psi)


.

[GoWestMan]

So only 30 psi while highway cruising? And 75 psi is the max it should hit.


Mine's definitely higher than all those at all times. Not sure why.

Originally Posted by Ray,IN

Cummins 8.3 oil pressure,

Lubricating Oil System
Specifications
Oil Pressure
At Low Idle (minimum allowable)........................................ 69 kPa [10 psi]
At Rated Speed (minimum allowable)...............................207 kPa [30 psi]
Regulated Oil Pressure.......................................... ..........517 kPa [75 psi)


.

[Craig1960]

Originally Posted by NorthOrSouth

So only 30 psi while highway cruising? And 75 psi is the max it should hit.


Mine's definitely higher than all those at all times. Not sure why.

30 in the min. and I'm guessing you may have a pressure regulator problem.