I was told I have a bad alternator but when Im driving I can here like a grinding sound but only while the truck is rolling??. I was told that when a alternator is going bad you can hear a grinding noise but could it be that? Because I've also spun the tires and don't really hear it could it be worn out rotors? And another problem is my speedometer needle sometimes don't work or sometimes it starts to bounce around a bit??

 

Take fan belt off and spin all the pulleys by hand you WILL hear if a bearing is going out

What year Ranger and is it 2WD or 4x4?

 

Ok thanks and it 4wd but I try to avoid using it because when I engage 4wd it tends to stay locked in for a while until eventually I manage to disingage it.

 

And it's 2003 4.0 sohc

 

2003 gets speedometer signal from the Computer(PCM pin 68), PCM gets its signal from the OSS(output shaft speed) sensor on the back of transfer case, rear drive shaft

PCM pin 68 feeds the speed signal out on a Grey/black stripe wire, to the speedometer, cruise, 4x4 module and GEM module

If you have Cruise see if it drops speed or acts funny when speedometer does, if not then problem will be in instrument cluster, may be loose wire?


For the 4x4 stuff, is sounds like shift motor needs some attention

Have the 4WD lights ever flashed when it doesn't shift to 2WD or 4high?
If not and it doesn't shift the 4x4 module may need to be replaced, the 2001 to 2005 4x4 modules where know to fail.
If the shift motor doesn't move when commanded to the 4x4 module will flash the 4WD lights on the dash.
So if it doesn't shift back to 2WD then lights should flash, if they don't then 4x4 module is most likely suspect.
If lights do flash the Shift motor is most likely problem

in 2003 the 4x4 module is behind passenger kick panel, it has a relay inside that should "click" anytime you select a different transfer case position
The 4WD switch on the dash is just 3 resistors and unless its been hit with a hammer they never fail, lol


Have a look here for shift motor: https://www.explorerforum.com/forums...-motor.123542/

Park on level ground, if possible, block tires so vehicle can't roll away
Shift trans to Neutral, then key off

Remove the shift motor, 4 bolts
Use vise grips to see if shift rod in the transfer case can be moved easily, if you are not on level ground you may need to rock vehicle to get it out of 2wd the first time
It should shift fairly easy and feel OK, hard to describe something like that, lol

Have some one shift to 4high and then 4low while you watch the shift motor, then back to 2WD repeat as you see fit.

 

Ok I will try that I'm not to concerned with the 4wd since I really don't use it but definitely the speedometer needle but I will do what you said appreciate the help!!

 

The PCM will set a P0500 code, and turn on CEL, if the OSS(speed) sensor on transfer case is the problem, so don't bother with that, even though its popular to change the speed sensor when speedometer is acting funny

The PCM get the 20,000ppm signal then converters it to 8,000ppm signal needed by speedometer, cruise, ect............

 

Ok i will take a look at that thanks!!