my oil pressure usually stays pretty low and i have a pretty bad leak. if i fix the rear main seal will that help any?

 

I doubt if your oil press is really low unless the engine is worn out. Try cleaning the sender contacts or replacing the sender. My gauge started reading correctly again after I unplugged the sender, sprayed it with WD40 and re-plugged it a few times to re-establish the electrical connection.

 

Ya my oil pressure was scarry at idle and when i changed the sensor the guages work properly!!!

 

The electrical sending units are known for being inaccurate. The best way to check the pressure is to do on a hot engine with a mechanical gauge to verify the pressure. 10psi is the minimum pressure at idle. I typically see 30psi at hot idle and it buries my 50psi gauge when I bring it off of idle.

 

the rear main seal is not pressurized and therefore wouldn't change the pressure either way. if it's a 2-piece seal those are fairly easy to change, but the 1-piece one requires removing the trans. i don't know which one of these the cummins is, but i'm sure that many others do.

personally, i don't mess with rear mains unless they are leaking VERY bad, or i've already got the trans out or the pan off, etc.

 

The rear mains seals are 1 piece and the only time you should fool with them is when its leaking or you have a transmission out. This will not help a low oil pressure problem if one really exists. Where is it leaking? Between the trans and the engine?

 

doesnt the main seals leaking generally indicate that your main bearings are worn, thus causing play in the crankshaft which in turn causes the main seals to leak?

 

Not necessarily, seals will eventually wear out from friction or foreign material on their own.

 

And some time that foreign material will put grove in the crank causing the new one to leak allso.....hypotheticially
speeking!

are you shore that its not leaking from the valve cover and down the back side of the block!

 

Or, when they are dried out and hard from not using the truck enough.

Mine was seeping a little when the trans was replaced. I brought a new seal along just in case and they put it in for me.