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Topic: Interesting Comparison Dash and VMSpc Transmission Temperature Gauges (Read 586 times) previous topic - next topic

Interesting Comparison Dash and VMSpc Transmission Temperature Gauges

We recently traveled to the Outer Banks and had the opportunity to compare the readings of the dash and VMSpc transmission temperature gauges. The sensor for the dash gauge appears to measure the output of the retarder, while the sensor for the VMSpc appears to measure the sump temperature. While the dash transmission temperature reading would shoot up very quickly when the retarder was used on the steep downgrades, the VMSps transmission temperature reading moved very slowly. The dash gauge would quickly move up to perhaps 250, while the VMSpc reading would slowly move to a maximum reading of just a little over 200.

Re: Interesting Comparison Dash and VMSpc Transmission Temperature Gauges

Reply #1 –
David, are you sure that there are different sensors for the two readouts? I suspect that the differences are in the readouts rather than the sensors, after all the VMSpc gets it's information from the wiring under the dash.

Re: Interesting Comparison Dash and VMSpc Transmission Temperature Gauges

Reply #2 –
Quote from: Horace B. Cupp –
David, are you sure that there are different sensors for the two readouts? I suspect that the differences are in the readouts rather than the sensors, after all the VMSpc gets it's information from the wiring under the dash.

The behavior of the two readouts is so different (when the retarder is being used) that I think the readings must come from two different physical locations.

Re: Interesting Comparison Dash and VMSpc Transmission Temperature Gauges

Reply #3 –
According to the technicians at Stewart Stephenson in Longview, there are two sensors in different locations. One goes to the temp guage, one goes to the light bar at the bottom of the instrument panel. Had the sending unit that goes to the sump go out about a year ago is the reason I got educated on this.

Re: Interesting Comparison Dash and VMSpc Transmission Temperature Gauges

Reply #4 –
Quote from: Forewheelers –
According to the technicians at Stewart Stephenson in Longview, there are two sensors in different locations. One goes to the temp guage, one goes to the light bar at the bottom of the instrument panel. Had the sending unit that goes to the sump go out about a year ago is the reason I got educated on this.

The transmission temperature light on the instrument panel illuminates when the dash gauge reads around 250 (and the VMSpc reading is under 210) and so I think the same sensor is used for the dash gauge and the instrument panel light, while a different sensor is used for the VMSpc indicator.