Hello everyone. So I just bought a 2002 1500 Quad Cab 4x4 4.7L with approx 150k miles. I got at a very low price...because it had a few issues. I figured I have intermediate mechanical and electrical skills, so I should be able to figure things out. But now I'm stuck.

After first scanning the codes, I had a few bad senors, so I replaced them; ABS sensor on rear diff, upstream O2, downstream O2 & that EVAP purge solenoid. Even after putting in the new sensors I get the EVAP and the O2 code for bank 1 sensor 1. I put in Bosch sensors, so I'm assuming that it may not like them...not a big deal I'll investigate that further.

The main issue is the fact that the speedometer doesnt work. This is bc my ABS module isn't communicating with anything. I ordered a replacement and plugged it in to see if the scanner would pick it up...and nothing. The replacement doesnt even scan. Fuses are all good. No corrosion or moisture on the plug. Doesnt look like any wires are damaged. Really dumbfounded at this point. Any suggestions on the ABS? I just replaced the FCM and I also ran a self diagnostic on the instrument cluster and everything is fine.

Also, my reverse lights suddenly stopped working. The bulbs are good and the fuse is good, but they dont turn on... Don't know what to do with that either.

Lastly, the truck seems to shudder/vibrate at low rpms under load. I've only noticed it in 3rd and 4th. I've searched everywhere I can with no resolve. I've replaced the u-joints, transmission oil, differential fluids, spark plugs, air filter, cleaned the throttle body along with the sensor in there. The truck itself runs great. I just cant stand the fact that the truck starts to vibrate when trying to maintain speed on the highway. As soon as I accelerate significantly, the vibration goes away. It's not felt in the steering wheel. You kind of just feel the truck vibrate as if you were going over a tiny rumble strip. It's not the alingment or wheel balance or CV joints. All of those are perfect. Makes me think that something is wrong with the transmission. It's just hard to accept bc it shifts perfectly.

I apologize for the long list of problems, but if anyone has any suggestions for any of my problems, they would be greatly appreciated. I also have a remanufactured ECM coming in today. I'm hoping that may clear up at least one thing.

 

Your rear lights may be because of the reverse sensor in the transmission. I had the exact same problem with my 98 Jeep Wrangler and that's what it was. Just have to pull it fast and put the new one in. I think it sits out of the transmission fluid unless it is jacked up. Just a suggestion, but I don't have anything else to say about your other issues.

Good luck!

 

thanks. I think I'll have to replace that. by the time im done figuring out all these problems ill put together a brand new truck lol

 

You may need another tranny, Or at least a rebuild of the current one. All your problems seem to be tranny related. I dunno. lotta miles for sure. speedo is run off aa sensor in the tranny so is the reverse lights.The shudder is an obvious tranny problem. replace all tranny sensors and fush tranny. Thats about 400 bucks , but cheaper than a rebuild. Keep us posted,

 

I was under the assumption that the speedo sensor in the tranny has actually nothing to do with the speed shown in the cluster...at least not int he 3rd gen Rams. I might replace it anyway since its only a few $'s. I dropped the pan on the trans the other day. When I poured out the fluid, i found two metal pieces in there. The two pieces were identical. They looks like zig-zags. I looked all over the parts diagrams for the tranny and cannot find anything that resembles what I found. I'm starting to second guess myself since I didnt actually see the pieces fall out of the pan. Maybe they were from something else and were already laying in my oil catcher thing? Other than that there was just normal metal dust on the magnet. The studder seemed a little less noticable after the fluid and filter change. I'll have to do the sensors this week.

 

Did you drain your rear diff. The pieces of zig-zag could be the rear diff clutch retaining clips. All these problems with sensors could be the pcm and or tcm (computers) and changing them out didn't fix the problems. I would check the pcm/tcm main harness and re-seat the plug-in connections. Good luck

 

^ +1
Sounds like your "zig zag" pieces are your "W" clips holding the LSD in.

nateroach

 

I would check the rearend VSS/RWAL sensor (again). It is the signal source for the speedo and ABS. Also I would check the trans mount as it may cause a vibration if broken.
Good luck...

 

yea what red said if the sensor on the rear end is bad or if the plug is bad then the readings to the pc are going send the wrong signals to the speedo AND the abs, and that plug back there catches all kinds of h@#

 

i hope this helps but i would check out the drive shaft balance, if your missing weights or the drive shaft is not straight, then that's your vibration. sorry can't help with the other problems.