Does anyone know for sure if the axle ratio is a perameter in the factory programming? I was told that it is not. I question this because I installed a limited slip 3.92 (originally 3.55) the thing is a dog and shifts strange. This has become a question AGAIN because I am not able to run my programmer.

 

I'm looking for more information to verify this but I can't see how the ratio CAN'T be in the programming. The PCM has to know the tire size/gear ratio to calculate speed and shift points for the transmission.

 

the gear ratio is not a perameter, but im pretty sure the speedo signal is. you will have to re-calibrate the speedo when you install a different set of gears, then you should be on track.

Also remember that now with lower gears, you arent putting as much load on the engine at a given throttle position as your used to. The transmission will try and shift sooner because the MAP, TPS and RPM tell it to. Im not 100% on these transmissions but you may be able to adjust something to compensate for this... it may even be as simple as adjusting the TV cable.

 

I swapped to 4.10's and a truetrac about a year and a half ago and only noticed gains.

That being said even the FSM is fuzzy on the info. A few times it refers to the VSS, as it does here (ripped from the speedometer operations section:
The PCM continually monitors the vehicle speed
sensor to determine the vehicle road speed, then
sends the proper vehicle speed messages to the
instrument cluster. For further diagnosis of the
speedometer or the instrument cluster circuitry that
controls the gauge, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING).
For proper diagnosis of the vehicle speed
sensor, the PCM, the CCD data bus, or the message
inputs to the instrument cluster that control the
speedometer, a DRBIIIt scan tool is required. Refer
to the appropriate diagnostic information.


but in the speed control section (cruise control) it says this:

DESCRIPTION - VEHICLE SPEED INPUT
Gas Engines and/or Diesel With Automatic Trans.
The Vehicle Speed Sensor (VSS) is no longer used
for any Dodge Truck.
Vehicle speed and distance covered are measured by
the Rear Wheel Speed Sensor. The sensor is mounted
to the rear axle. A signal is sent from this sensor to the
Controller Antilock Brake (CAB) computer. A signal is
then sent from the CAB to the Powertrain Control
Module (PCM) to determine vehicle speed and distance
covered. The PCM will then determine strategies for
speed control system operation.

With the gear change the speedo read fine, shifting wasn't any different. With a tire size increase, the speedo was off. Go figure?

EDIT: I have been told the the RWSS reads the tone ring in the rear axle and that regardless of gearing the speedo will be correct. but that the tone ring won't compensate for tire changes.

 

You CAN adjust shift point for ALL gears with the TV cable:

http://www.bionicdodge.com/Download/...Adjustment.pdf

 

I thought 3 & 4 were electronically controlled?

 

I hope you mean everything that doesn't include the torque converter.

 

a converter isn't a gear.

 

just clarifying as neon thought you ment something else.


EDIT: LOLZ I forgot you blocked him aim... you prb didn't see the post then HAHAHAHAHA

 

I have adjusted the cables which did not effect it. It feels as if I am going into overdrive at 40mph at times. I also get what feels like a double shift when Im on it. Torque converter issue?