My son has a 1994 Ram 1500 5.2L 2WD (~125k miles). Recently the oil pressure began dropping to zero and the oil light would come on when the truck was idling (at traffic lights or just in the driveway) -- checked the oil level and it was fine. When the RPMs increased the pressured shot back to "normal." Put the truck on jack stands and it sat for a week. Decided to replace the oil pump and did with no issues -- actually a relatively straight forward job with no complications. rolled the truck off the stands -- the oil pressure problem seemed fixed, but suddenly the transmission would not shift (stuck in first) -- no previous problems with this. changed the transmission filter and have checked transmission fluid levels (seems good, may actually be a little high). truck now shifts normally, but is very noisy (almost a rattling sound). Oil pressure seemed fine until 2 days ago when it began dropping to zero again when idling -- I'm puzzled about both issues (oil pressure drops and the noisy transmission). Any thoughts or suggestions?

 

Did you change the oil pump pickup/screen?

For the noise, you might have bent the trans access cover taking the oil pan off. It may be pushed in hitting the flex plate.

 

Verify oil pressure with a mechanical gauge. If the m-gauge says its ok, replace the oil pressure sending unit.

 

Thank you for the quick replies.

Yes, we changed the pickup screen as well -- i like your suggestion about the bent access cover possibly causing the noise. Will also check the oil pressure with a mechanical gauge and post back the findings.

thanks again for the suggestions.