I did the potemtiometer install last night. Everything went pretty good until I went for a test drive. The speedo, cruise, overdrive still are not working. The weird part when I drive the truck is while adjusting the "Pot" control ****, the check engine light and several message center lights briefly flash on!!???

What is the wiring match-up between the "pot" and TPS female plug????? What can happen if you mismatch the 3 wires? I just don't want to fry something. Need some help on matching the wires correctly.

 

did you follow these directions?

https://www.dieseltruckresource.com/...al-t42003.html

was the speedo working prior to this?

 

Ditto. If your speedo isnt working then it might be a bigger problem.

The POT mod doesnt fix anything but the problem of having to deal with the throttle position sensor.

Sounds like you have other problems at hand...VSS, CPS, PCM....

 

Check the connectors at the bottom of the steering wheel....
Mine work loose every 10K miles or so.
Don't know how or why but there is slight play in them. When I tighten them up, all the problems stop.

 

So let me get this straight................. The potentiometer upgrade for the TPS is not a fix for Overdrive & Speedometer not working???? I have had intermitant problems with the OD kicking off and losing my speedo. Most members reply: "Oh yeah, dead giveaway.......its the TPS!" So, I follow the crowd and do the TPS - potentiometer upgrade. This has not fixed my problem at all. Here are the facts:

I have experienced the speedometer bouncing and then quickly losing overdrive 6 seperate times since buying it back in 2007 Every single time the speedometer has bounced a few times and then OD went out.

I have a new Dodge dealership VSS installed

All wires/connections are clean and not damaged

The transmission has been fully rebuilt with all new parts just 3 weeks ago.

The new transmission has about 250 miles on it.

I'm really sick of this OD intermitant junk I pulled off the new VSS tonight and hooked a cordless drill up to it. While the drill was turning the squared shaft, the speedometer moved flawlessly!!!! I then hooked up the VSS to the transfer case and test drove...........nothing! no workie! So......is it something screwed up in the transfer case? I have seen pictures of little plastic gears inside. Could these plastic gears be worn out? I'm starting to run out of options on why the speedometer randomly quits, therefore losing Overdrive.

 

Your overdrive kicking in and out; Yes, that can be a definite sign of a bad or misaligned TPS.

But, the speedo bouncing around randomly leads me to think it something else is the problem. When my TPS went out my speedo worked fine.
Even this past week with a 'dead' computer my speedo still worked, as long as the computer was still plugged in.

2 years ago or so whenmy VSS went out, the needle would hop constantly and it would cause my overdrive to kick in and out.

Perhaps yours has come loose...?

When mine would come loose, the speedo would jump around like crazy. It almost sounded like the needle was going to break off it was jumping so hard. Id have to pull over and twist and tighten the VSS up again and it would clear things up for a couple of miles or the next day.

But, the plastic gears in the transfer case may be the issue. Ive never had to deal with those though. Perhaps someone who has, or has had experience rebuilding these t-cases knows.

 

It sounds like the VSS drive gears are shot. If your truck has a ratio adapter between the transfer case and the VSS that is another source of trouble.

When the VSS drops out, the PCM thinks you have stopped and kicks you out of OD. The pot will only "fix" a bad TPS.

 

The VSS itself is almost brand new from the dealership. I also put a cordless drill to it and the speedo worked. I took out the ratio adapter 2 years ago because it gave me intermitant trouble. Wannadiesel, are you talking about the drive gears beyond the VSS (inside the transfer case)??

 

Yes, it sounds like those are the problem. It's that or a flaky connection somewhere.

 

I read some older threads on here about the VSS, speedometer, etc and how they work. I also learned that 4WD & 2WD pickups have different VSS gear drives. So, with that said........... what is beyond my "all-metal" VSS gear drive? I included a picture of what I'm dealing with. I am curious as to what the small metal pinion rides on inside the transfer case. Does anyone have a good picture of how this assembly looks inside the transfer case?

 

At this point I am about to do some more troubleshooting on my speedometer not working. I realize that the OD and cruise control not working as well is just a side symptom of the inop speedo. I would just like to set things straight in my mind: What are all the pieces/parts that can affect the speedometer and cause it not to work anymore?

 

Ok, I just got done troubleshooting and discovered one thing that did not make sense. I decided to use pictures to tell the story. Just an FYI, the VSS & ratio reducer are new from the Dodge dealership.

Any ideas or suggestions?

 

I discovered that the Pinion Drive Gear has a worn out and rusted female coupling. The male end of the speedo gear ratio reducer has nothing to grip onto since the female part is rounded and rusted. Sadly I called the local Dodge dealership and they explained that the part is no longer available and discontinued!!!!! Yikes! I need this part to get my speedo and overdrive to work correctly again. The part number is:

4329816 (16 spline teeth) Here is a picture of it:

 

That'll do it.

You could try cleaning it out real good, filling it with JB Weld, and then pushing a greased stick whittled the same size as the VSS drive into the JB Weld until it sets up.

 

Nice job on using the old grey matter, that's one i'll file away and remember