Hi all - my Check Engine light is on and it is throwing a P0720 code which indicates an OSS (output speed sensor) malfunction.....I know the sensor is on the transmission, but I'm not exactly sure where, or what the sensor looks like....will cost approx $120 for the mechanic to fix, but I'd like to do it myself if possible.....anyone know of a schematic drawing/illustration I can look at to see where the sensor is located? Anyone ever change this on their own? I'm just not sure exactly where to look on the tranny, or what exactly the sensor looks like. Thanks for any help!!!!

 

Just had another speed sensor prob on a '99 4x4. Speedo intermittent, ABS light, engine would die when clutch was pushed in, which led to the engine light a couple times during the week it took me to get time to fix it. (CEL would reset after a couple of heat cycles) Got a part from an unnamed local parts supplier that I think was the tranny speed sensor you might be referring to. In researching on here I determined it was probably the rear wheel speed sensor vs. the one on the tranny. Couldn't find the one that they sold me anyway (on my truck), so I went to Advance for a 2nd opinion and got the rear wheel speed sensor for $30. Voila - problem solved. Anyone that can tell me why this particular sensor failure would lead to the engine dying? Speed tied into the computer and the EFI somehow? Thanks.
And good luck finding the one on the tranny.

 

Went to Autozone - guy came out to look for location.....believe we found it....just before tranny connects to transfer case saw what looked like sensor....unplugged wiring harness then plugged in new part to wiring harness....fit perfectly, but I'm going to see if Dodge dealer has schematic that I can look at to make sure.
Hope someone knows what led to your engine dying!

 

Got a schematic from the dealer, proetty good drawing, but didn't show the exact location....guy I talked to verified what I thought....sensor on transmission, driver's side, just in front of transfer case.....will attempt to fix tonight!

 

Lost about 50ML of fluid in swapping out the OSS.......QUESTION: Is that a significant amount? Should I add 50ML back?

Anyway, this was an easy fix to replce the Output Speed Sensor. Took me about a minute to swap them out.......made sure I had a pan underneath to catch some of the tranny fluid that came out.

Cost me $20 for the part and to fix myself......garage would have charged $130+ to fix.