Well after driving pass one of those Whats your speed warning signs, I have found that my spedo is off. Between 5 to 10 mph (drove past it several times cause I was trying to figure how off it was).

What little R&D I could do online (via google) there is very little information on how to trouble shot/fix this. I see there are two different speed sensors (manual to elec impulse & impulse). There was also something I saw about re-calibrate the cluster but didn't say how to do this.

Chilton manual is about as helpful as a box of rocks, wish I had a FSM (might have to dig around for one) But thought I would ask here first.

Oh and on a side note, does anyone know of a Energy Suspension Transmission mount for these 97's? The part store anchor mount says will fit but when you cross it with the years it says 99 and up. When I look at Energy Suspension's web site, there is nothing listed for the 97's at all.

Thanks in advance

1997 Dodge Ram Van 2500 w/ Mark III conversion
5.2 auto
2 wheel drive w/ tow package
tire size matches door sticker 235/75/15

 

Don't know if I would trust one of those "Your Speed" traffic gizmos more than your speedo. Really easy way to double-check is to bring a TomTom or Garmin portable GPS unit with you and see what that says for MPH as you drive.

For '97 the speedo is still mechanical so if the MPH indicated while driving is verified incorrect I'd suggest just replacing the speedo with a junkyard unit rather than spending money trying to fix or calibrate yours.

I have a few clusters saved from previously owned vans with the mechanical speedo you would need - PM me if interested and we can work something out I'm sure.

 

Gone past plenty of those speed readers and they are spot on with GPS speed. Infact most vehicles are out by a good 5 mph on their instrument panel. (a good 400 Ford E 350 Van in the fleet I drove to prove this) one brand of speedo was out by 8 or 9 MPH. I just ended up getting a GPS and using that, even turned off the dash light, and just used the GPS. speedos are have a large range of tolerance they are required to be accurate.

 

Are you sure it is mechanical? It seems that the speed sensors are electronic not cable (one for the tail of the transmission and one for transmission speed). Maybe its not the speedo at all, it might lay within the PCM seeing as they are electronic impulse.

A spare cluster is always a good idea to have around for mod work or customizing

 

A more precise statement would be to say it is electro-mechanical. The speedo does work off readings from a sensor (there is no spinning cable from the trans) and I believe the odometer and trip odometer are turned by a small stepper motor. The gauge is analog, of course.

 

UPDATE:

Alright I checked tire size they are spot on 235/75/15
I have read up and seems that there is some ways to check the electronics to the speed sensors. But the FSM that I ordered can take up to 6 weeks or more before it gets here.

My Speedometer is off by 10 MPH, ran side by side a buddy and they went to 55 spot on and my speedometer reads 65 (roughly) to be doing the same speed.

I have read that most have to take it to the dealership to have it set, I would like to make sure that is the problem before I go dumping money at a dealership to hook some computer up that can make more problems for me in the long run (as we all know how they work to make sure you have to return and return and return and return)

 

Our VSS for the speedometer are installed on the transmission. According to my FSM the speed can be off for any of the following reasons: Incorrect tire size, incorrect axle ratio, a faulty or incorrect speedometer pinion gear or a faulty VSS.

When you get your FSM check page 8E-9 for more diagnostic information for there are several things to check and the procedures are in different parts of the manual. That page will give you much more information.

 

Wont be for several weeks (almost 2 months) before I can look at the FSM or ordered. I did pickup the VSS (both sensors) they were cheap enough. The clips and wires look good, so might just switch them out and see if it corrects it. If not then left with the gauge cluster.

Already looked at the under hood tag and what info I could find off of it, along with checking with the dealership (Chrysler) for the build sheet. Crossing with the ID tag on the rear end, that rules that out.