OK so I looked through the diy links and didn't find anything. What all is entaled in changing the oil pump? I got a 99 360 4x4 and I believe the oil pump is going out. Basically when I stop my pressure goes to 0 but I give it some throttle and it goes up then drops when my rpms get below like 1000 any thoughts?

 

I've never changed one out myself but I have read through the DIY's too and I think I recall the basics.

I know to get the oil pan off you need to either jack up the front of the engine or take the trans inspection cover off to get it to come off. Then I think you need to take the last crank bearing cap off to get the pump out. Then take the screen and tube off and take out the pump.

I know the way I put it it sounds pretty easy, but again, I've never done it and it would probably be a Sat. or Sun. project to take your time and do it right. I'm sure more people will chime in and add/correct my advice. Good Luck!

 

does my symptoms sound like an oil pump

 

it could be a pump. but it could also be excessive bearing clearence. you might be able to get away with using a thicker oil, like 15-40. when you change the oil, check for a metallic shimmer in the old oil when you look at it in the light. this would indicate alot of wear on the internals, most likely bearings.

 

I have the exact same problem. I have a 1999 Dodge Ram 1500 SLT 4x4 5.2L. It has 180,000 km on it ( I'm from Canada so I don't know the conversion) but I noticed that it got worse when I changed from 10w30 to 5w30 for winter. We get -40 celsius up here. I went thru the whole thing with the oil pres. sending unit and instrumnent cluster at a shop but was told that I needed a new motor because it doesn't have enough pressure at idle in gear. 4psi. I also talk to a guy who has 20 + yrs as a mechanic you says the same thing as helms did...oil pump or bearing clearance. But he also told me that Dodge motors have a problem of getting lots of sludge in the pan and it might clog the pump screen. I am probably gonna have the pan removed and cleaned and replace the pump with a high volume pump. I hope I can get it fixed right cause even though it has high mileage, this truck is mint...long box, regular cab 4x4, just what I was looking for... it's the only truck my chopper fits in!

 

Changing the oil pump in our Magnum engines is a simple process. I did this in my 2001 in about 30 minutes and that was taking my time.

For my 01 I had to remove the starter, transmission dust cover, and both transmission to engine brackets. The brackets are just long bars that bolt to the sides of the engine. My truck had enough room to remove all of the oil pan bolts and drop the pan. I have heard some members have had to lift their engine a little to get enought room to pull the pan out.

The oil pump has 2 bolts that hold it in place. When you remove these the oil pump pulls right off and may actually fall off so be careful. Also, the oil pump shaft runs directly from the bottom of the distributor to the top of the oil pump. Be careful about this falling out onto you. If it falls out it can be re-inserted, but make sure it gets seated all the way back onto the distributor.

You can re-use your oil pump pickup screen or just bite the bullet and buy a new one for $20. I bought a new one. I would recommend for higher mileage engines buying a Melling High Volume oil pump. While at the parts store take it out of the box and inspect it for cracks in the following places.
1) Where the oli pump shaft inserts into the top of the pump.
2) In the cast metal that surrounds the oil pump shaft insert.
3) Around the oil pump bolt holes.

Also manually turn the oil pump by spinning the piece where the shaft inserts. You may be able to do this with your fingers or may need the appropriate size allen wrench. Only spin it with your fingers. If it does not move smoothly without a ton of effort, tell them you want another one. I had actually receive a broken one so that's why I recommend checking it.

When installing the new oil pump, extra care needs taken to ensure you fully seat the pump to the engine block mating surface. Don't forget to use the gasket they provide with the oil pump. It should not need any sealant on it. Do not use the bolts to snug it up because the oil pump casting will break and its back to the parts store for you. When you are 100% sure it is mated properly to the engine block surface you can tighten your bolts. I'm not sure of the torque specs but again take the extra care.

Reassembly is the reverse of taking it apart. The oil pan gasket is a reusable rubber gasket so unless yours is damaged, you do not need a new one.

Good luck.