I am new to the Dodge world. Just got my first- 1998 Ram 1500 Laramie SLT. Got some help here with an engine whine- turned out to be just the belt and the idler pulley. Had some other issues I thought I would post- though many of you likely know these tricks, anyway.
1. The ABS and Brake lights were on.
2. The speedometer would not work until I reached 30mph.
3. The tranny would not shift out of 1st until I reached about 3500-4000 RPM.
4. The check engine light came on.
I did some research and found out that I needed to replace two sensors: the rear speed sensor (located on the rear axle) and the transmission output sensor. About $60 for the parts (lifetime warranty) and 30 minutes worth of work, and all problems solved.
Truck runs great now, and I now feel like my $2k was well spent.

 

OMG! I am having the same problem with my 2000 Dodge 1500 4wd. What transmission output sensor are you talking about? The sensor on the tail shaft?

 

Except you left out the part about the abs,brake lite and speedo not working.

 

Attention to detail....lol

 

Yes, the output sensor I replaced is on the tail shaft. If you're directly under the transmission, it's at about 7:30 looking from the back, 4:30 looking from the front. It is white plastic and really easy to replace (watch for fluid to possibly come out when you remove it. I turned my truck around in the driveway and pointed the front downhill and didn't have that problem. The other sensor (rear speed sensor) on two-wheel drive is on the rear axle at the top- I'm not sure where it is on a four-wheel. I replaced both, but some of my reading says it may just be the output sensor, and not the rear speed sensor. Since it was just $60 for both, I did both.