Speedometer/Gear Change?

[Snellville-Dave]

I've been planning on changing my differential from 3. 55 to 4. 10. Have called several Dodge dealers about getting the transmission/speedometer reprogramed to match the 4. 10 gears - have had answers farings from ya we can do it for $89. 00 to don't need anything changed. One dealer said to call a speedometer repair shop to get speedometer adjusted to match new gearing. Called a speedometer shop and they said they would have to install something that I didn't understand and that the total cost would be $285. 00 to get the speedometer corrected. Need thoughts about should I just get the gears changed and use the tach to judge speed, etc. and not worry about anything else.

 

[jelag]

When I brought a 01 down from Canada the speedometer shop that did the change out... had a connection to the computer and toggled it from KM/H to MPH and the odmeter was also changed..... both at the computer... with a new backface on the gauges for the American Standard based on DOT standards... . in talking to the guy he told me he also did corrections for oversized tires..... so I'm guessing that this is reprogram of the ECM... .



The guy here in Spokane does 300 plus of these a year for a local importer and dealer... his charge to me for the change over was 150... cheepest in town... . his guy drove up to my new truck and in 20 min drove away... . all done..... he exchanged the dash..... and did the reprogram..... you couldn't ever tell it had been touched... . the key is that he has to back his work for 7 years to meet DOT standards and had to put a sticker in the door jam.....



Jim

 

[jrobinson2]

The speedometer gets its signal from the tone ring in the rear differential, it counts tire revolutions not driveline revolutions so you shouldnt need to change anything. The dealer can reprogram the PCM for different tire sizes using the DRB scan tool.

Jared

 

[Thomas]

And the tone ring is the same part number in a Dana 70 axle regardless of gear ratio. Same with the Dana 80 axle. I don't know about your Ram 1500.