Engine/Transmission (1998.5 - 2002) Oil Leak

[Bobalos]

I was under my truck this weekend (99, 2-wd, Auto) & it kind of looks like the oil pan is leaking from the cross member back. its pretty dry & clean from the cross member forward. Its kind of hard to tell though, because its pretty dirty about 3 or 4 inches above the oil pan. I suppose it could be oil blowing up there, but... ... ... ...



I tried to snug up the oil pan bolts, but they were all prety snug.



so, my question is, does the pan leak much?



is there a rear main seal on the Cummins motor like on a small/large chevy that can leak? there does seem to be a lot dirtier the more aft I go. the Torque converter inspection cover & the front of the trans pan is covered in oil/grease/dirt. Kind of like the steering linkage thats covered in oil from the vent.



thanks guys.

Bob

 

[nps]

Wipe it down clean, run it, and get up underneath to see where it is coming from. I thought my rear main was leaking but found out instead that it is coming from the block-off plate that is used as the lift pump mounting bracket. A whole lot easier than dropping the transmission.



Could be the valve cover gasket, vacuum pump, vacuum pump oil return line, turbo oil return line, a blocking plug, or maybe even the oil pan gasket itself.

 

[Nate]

Good luck!



My truck was a leaking mess when I bought it. I think I've got it all fixed now though.



Front cover seal, Vac pump seal, power steering pump O rings, steering box, turbo drain line, transmission lines and pan, transfer case output, pinion seals on both axles, front axle carrier seals.

 

[Bobalos]

Goodness... ... ... ... ... ... ... . I guess I need to clean it all off & check it out. I hope its something simple... ... ... .



thanks guys

Bob

 

[Joe Mc]

Bob - Like nps the LP mount/mechanical LP block off plate was leaking on mine too. When I moved the LP back to the frame I used a Chevy Big Block fuel pump block off plate and new gasket in place of the big Cummins factory LP mount - no more leaks.

 

[Tiger Rag]

I stopped using synthetic oil and what do you know..... no more leaks. I'm using standard diesel oil 15w40 and just changing it more often now. From what I understand the synthetic molecules are smaller and the oil generally flows better (dependent on weight and temp I guess), but the standard dino oils larger molecules can't get through some of smaller opportunities at a leak. Anyway, just thought I'd pass along since it worked for me. Someone had suggested it to me and although skeptical, I finally decided to switch and low and behold it did work. Good luck,

 

[Bobalos]

Cool, more stuff to check out. now all I have to do, is to open the manual & find out what the heck you guys are talking about. this aint no Cheby motor. ROFLOL.



Bob