I have a 1994 Ram 1500 4x4 and was wondering what steps to take to solve this problem? I changed the oil and filter but did not help.

 

wheres your pressure at if its really low you may just need a rebuild

 

When troubleshooting and unsure of the problem, always start by replacing the cheapest parts first.

You changed the oil and filter, great.
I would run the engine for a good 20-30 minutes, then check the oil.
Probably easiest to do this after a bit of a drive, so wait until you do that.
Or, if the truck has already ran (after the change) for a good period of time (really at least 30 minutes straight), you can check it now.
When you check it, if it's black, you need to change it again.

If it's not black, I'd replace the sensor next, see what that does.

 

Yes I agree about the sensor. I had the same problem and a new sensor did the trick. It's a bugger to get to but it can be done. Here's a tip, invest in a 1 1/16 deep well socket and make sure it will fit over the sensor. That will make the job a WHOLE LOT easier.