September 2, 1998

TT #6 Instruments And Gauges Part 2

By: Rob Lowe

Technical Tips #6 


Instruments & Gauges (Part 2)

The Transmission Temperature gauge is a valuable instrument, protecting one of the most delicate components in the powertrain of our Bounders. Heat is the arch enemy of automatic transmissions, yet by the very design of this transmission, heat is generated. The chassis manufacturers address this by supplying radiators equipped with transmission cooling sections and auxiliary transmission coolers mounted in front of the engine radiator. Most transmission temperature gauges measure the temperature in the oil pan of the transmission; better quality instruments measure the temperature of the fluid leaving the transmission (after receiving the heat) and entering the transmission (after being cooled). The differential in temperatures is usually 40 degrees Fahrenheit.

As one surveys the market for quality instruments and looks at the dashboard of the Bounder, you quickly come to the realization that there is not a lot of room for additional instruments, such as tachometer, vacuum gauge, and transmission oil temperature gauge. Placing them within the dash panel is impossible, adding them around the panel can be unsightly. In Class C motorhomes, many owners have mounted these extra instruments from the roof near the rearview mirror, similar to those found in new cars and vans. However that is quite a stretch in a Bounder. I added a tachometer and vacuum gauge on the left side of the dash, mounted flush with the instrument panel. This winter, after researching instrumentation, I chose a gauge package made by VIP Systems known as the Sensitor 1060 to view transmission temperature and several other functions. This digital readout, electronic instrument monitors seven items, sounding a warning alarm and flashing light emitting diodes (LEDs) when an out of range reading is detected. First advertised about one year ago in MotorHome magazine, then evaluated in the November 1996 issue (Page 79), I decided that this package would suit the Bounder, both in terms of quality of the information it provided and in locating the room to install it. The unit monitors outdoor temperature, engine oil pressure, battery voltage, and the temperatures of engine oil, water coolant, and transmission (both in and out). It provides two green LEDs for each parameter and a manually selectable digital display. The system gives three levels of alert all accompanied by a warning tone: "Caution" (a reading is outside of the norm) with two amber flashing LEDs; "Warning" (a reading is in the danger zone) with two red flashing LEDs and "Fault" (a sensor has failed or become disconnected) with two amber LEDs. The warning buzzer is disabled by pressing a MUTE button and you can monitor any specific function by pressing a SEL button to get the digital readout. A recent improvement is a scan function that allows regular scanning or the readings of all functions. I mounted the display panel on the instrument panel centred over the speedometer and other factory gauges. It looks as if it was part of the factory-supplied instruments. By comparing the digital display to the Ford instruments, I was able to calibrate the Ford gauges and determine that they are quite accurate, displaying coolant temperature changes as little as 3 degrees. Using the Sensitor, I can determine what specific reading Normal is.

Installation of the Sensitor 1060 is about a four hour task, with all high quality components being supplied. The display adjusts its brightness to the ambient light conditions. A feature I appreciated driving back from Florida in March, was the warning that the outside temperature had dropped to 35 degrees (F). This feature warns you of impending black ice conditions, which in motorhomes can be quite treacherous. It is interesting to note how much the engine oil temperature rises climbing a long grade and how much difference wind conditions make to effective cooling, even in cool weather conditions that we experienced this spring. The Sensitor 1060 is available from rv-parts plus.com.


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