Originally Posted by ArcticXJ

Hi all, just finished my NP231 fixed yoke conversion last week, and while I was worming around under my XJ installing the Advanced Adapters kit, I was staring the ugly leaks coming from the transmission and oil pan right in the face. I knew the leaks existed, but now they are really bugging me (they're really not that bad but I'm paranoid about my driveline and they will only get worse). So I am planning on resealing both and putting in some new components (trans filter and oil pump) in the process. My quest for a straight answer using the search function yielded no satisfactory results about high-volume oil pumps. My understanding has always been that oil pumps create flow, not pressure, and the engine creates pressure on it's own (sorta, without going into detail). But others have stated that high volume pumps can create too much pressure and rupture gaskets/seals? Also, some claim that the high volume pumps can sump the stock oil pan dry? I'm thinking that since no one can give a straight answer for the pan capacity problem I will just get an aftermarket pan, but the overpressure issue is still there. So is the overpressure concern a real issue or no? (All my internal engine components are still stock) Please no huge arguments about the subject (that's why I have to ask in the first place), I just need a straight answer from those who have been there and done that, good and bad experiences. As always, everyone's input is appreciated.

Originally Posted by LittleRed94

I can't speak for the 4.0 but I know in 1.8 and 2.0 Honda motors you can use high flow oil pumps without rupturing seals and gaskets.

Originally Posted by Turbo X_J

No oil pump ever made will magically replace the cam bearings.

Originally Posted by TheGreatGazoo

I put in a high volume mopar oil pump in my 89 4.0 at around 100k miles. before I installed the pump I had around 5psi at idle in gear warmed up. at highway speed about 15 psi. after replacing the it with the mopar high volume pump around 20 psi at idle and 45 highway speeds. I currently have 189,000 miles on my 4.0 it works great for me no ticks or knocking when running. my engine builder always installs high volume pumps in my motors I even have one in my 440 CI in my 1969 roadrunner. all engines are using stock pans.

Originally Posted by ArcticXJ

They don't need replaced, if I get in there and inspect them and they are worn, then I'll replace. NOTHING is wrong with my engine, other than a leaky rear main seal. I HAVE good oil pressure and everything. However, I think it would be a good idea to replace the oil pump since it has 165,xxx miles on it. I'd hate to spend the time resealing everything only to have an old (or crappy aftermarket) oil pump go out. If I am going to replace, I want to upgrade. That's what I do with everything I replace. A bigger oil pan would help with cooling. That, coupled with a high-volume pump, would be really pampering my engine as long as the pump does not create "overpressure", which is what I want. Less wear, more cooling, longer service life.