98 ram 2500 360 4x4 250k

the problem:
occassionally when the truck comes to a complete stop the oil pressure drops to 0psi. When I hold the brake and get the truck to 1000rpm's all is well again.

I am going to change the sending unit in the morning, but was wondering about the oil pump due to the age and mileage:

1. this obviously is not a performance vehicle etc therefore will installing a high volume pump on my truck have a negative effect?

2. if I am changing the pump and pick-up screen, do I need to use any type of thread sealant on the threads of the pick-up tube when threaded into the pump? my first thought is no, but the manual says to ensure its tight so air is not introduced into the oiling system. I am thinking I do not want to introduce any contaminates into the oiling system via thread sealant tape etc.

3. should I go ahead and replace the pump drive shaft? if so, how? i do not see anything in the manual on how to do this

any other thoughts are welcome.

 

a friend of mine had this same problem with his 97 ram. it was the oil pressure sending unit. but your case may be different. as for the other questions im not sure but i would like to find out as i am replacing my oil pump in about a week.

 

edit: nevermind...

 

1. no negative effects of a hi-vol pump except it costs a few more bucks. positive effects are it masks some loose bearings on a higher mileage engine and might improve your oil pressure back up to normal.

2. i'd put a round or two of teflon tape on the pipe threads. it'll give you a little leeway on twisting the pickup tube to the down position. keep it to a mimimum and trim off any excess to avoid loose pieces. unless its damaged or hopelessly sludged up, i see no reason to replace the pickup pipe and screen. just remove your old one, clean it good, and reinstall in the new pump. DO prime the new pump.

3. no. i think you'd have to remove the distributor, which is a major no no. do not remove or rotate the distributor.

4. replace the rear main seal. its a 2 piece seal that slides in around the crank. lots of info here at DF and a very good DIY over at pavementsucks.com. use the rtv and anaerobic sealer exactly as specified

 

1 - You don't need a HV pump. I didn't use one on my just dynoed 408 (412 RWHP), infact it could do more harm than good. Some of the HV pumps have blowing up oil filters of late. Absolutley no reason to run one a street motor unless it's worn out....

2 - Thread tape and as said prime the pump...Some builders put vaseline in the pump gear so it does not run dry at all.

3- If you do use an HV pump you willl need to run a hardened intermediate shaft, I run one with the standard volumn pump anyway, I run 20-50 oil in the 408, so it's under stress as it is.

 

I was having the same thing happen with mine, I replaced the oil pump thinking the old one was getting worn out, and there was no appreciable change. Thee were no odd noises when the guage was at 0 though so I put a good mechanical guage on, tee'd into the stock sender port, and the lowest i've seen on the mechanical guage is 18 psi. Also, since I added the guage, the stock one hasn't dropped to 0 again.
Gord.

 

the oil sending unit PITA I cant seem to get the 1-1/16 specialized socket (deepwell) all the way on. any ideas??????????????

 

if you still have the original with the 12 sides, but, no little dent in them, try 1 1/8th.

 

got it off simply by slipping the deepwell as far as it would (about 3/4 way down) and snapping the plastic off by torqueing sideways. Had no issues getting the socket on after that. Changed the sending unit, oil change (mobil1 10w-30 full synthetic as always), new filter, pcv valve etc. 13-17 psi at idle. On the cold start up it was about 55-60 psi (not sure if that's normal) It was definitely a bad sending unit or should I say oil pressure switch. Therefore I am not changing the oil pump.

 

for about a year or so my abs light has been on. I knew it was on the passenger side and when I changed the front bearings at that time (4x4 not cheap) I order them from Rock Auto to save some $$$. After installing the bearings the abs light came on and I figured the sensor was fractured by some irresponsible shipper due to dropping package etc. In my frustration lying across the motor working on this sending uniit, I took a breather and looked down the inner fender to see the abs wire was broke, fixed that - yay no more dash lights.