Hi,<br />I have a 1995 Dodge Ram 1500 4wd 5.9L<br />My speedometer jumps up and down but usually just doesn't move at zero. My cruise control also stopped working. I replaced the<br />speed sensor on top of the differential and also did some work on the tranny and fixed shifting problems I was having yay! So Im <br />troubleshooting the speedometer/cruise control issue. I tested the connecter terminals per the service manual. I'm getting no voltage<br />when i put + probe to terminal 3 sensor supply and - probe to terminal 2 sensor ground. Should be 8 v<br />I'm getting .07 volts when putting +prob VSS signal to terminal 1 and - - probe to terminal 2. What do I do next???

 

Your truck has a speed sensor in the output tailhousing of the transfer case. That is the sensor you want to pay attention to. If you aren't getting voltage to it, time to start following the wire back to the pcm, and see where you are losing power.

 

I am getting power to the speed sensor. tested with my meter. I have a brand new vss installed (2nd one) and I have it aligned correctly.
I did the checks on the speedometer cable ports that connect behind instrument panel per the manual, all checked ok. all this and still my speedometer
either bounces around crazy, or doesnt do anything at all, and no cruise control. **There is this...... When I install the VSS and drive to test the speedometer
works at first up to about 20-25mph but then goes out again. Please help.

 

How does the drive gear on the t-case output shaft look? Same for the driven gear that actually turns the VSS. (it's just a signal generator.)

 

Your VSS sensor on the top of the differential is only for ABS function. It senses if your wheels are spinning at different speeds activating the ABS system.
Your speed sensor (one that controls the gauges) is on top of your transfer case.
Check all the connections there and replace if necessary.
Check if this speed sensor was installed properly.
There is 4 separate "clocking" indentations on the sensor housing. Make sure they are positioned correctly where there is smooth engagement between sensor gear and main shaft gear.
Hope this helps

 

I don't know exactly what I'm looking for, but I'll take a look and a pic and post it. I

 

The drive gear sometimes gets 'apple cored', so it works sometimes, but, at higher speeds, the gears just don't mesh properly.

 

Actually i took the vss out again last night and reinstalled it and it does start working ( the speedometer) at about 50 mph and up. So maybe you are right. I'll try and find what you're talking about heyyou

 

If I do find what you're talking about, what do I do about fixing it??

 

Replace the drive gear. (probably grey, reputedly a lot of fun to change......)