Cat 7155 Transmission-Winterization Kit (Control Block Strip Heaters) Installation?

[Mark Buller]

I am in need of some help with the installation of this winterization kit for the Cat 7155 transmission-- control block strip heater kit on my M920 & M916 Trucks. The kit came with 4 pages of diagrams--but only of the included items in the kit --NOT how to install it in the vehicle. I see that the strip heaters are clamped to the transmission control block and that there is a light installed in the cab showing the heating system is ON. However, there is no discription of HOW the system works NOR any instructions exactly how to install this kit . There are various components in the kit: 3X oil pressure sensor/switches, 1X temp. sensor/switch. 1X magnetic relay switch, wiring harness, the strip heater bars with insulation and covers, signal light for the cab, brackets & misc. hardware etc. I assume the magnetic relay is to provide main 12VDC power to the heaters....and I assume one oil pressure sensor/switch provides a 12VDC signal voltage to the magnetic relay to "close" (thereby supplying current to the strip heaters) with the other terminal of the magnetic relay going to a temp sensor mounted on the top of the transmission control block...this I assume is the GROUND for the magnetic relay ....i.e. when the control block is COLD, the temp sensor/switch is "closed " (providing a Ground) and when the control block is warm , this temp sensor switch...breaks the "ground" for the magnetic relay ....thereby opening the magnetic relay contacts---and cutting the power supply to the heaters i.e shutting the heaters off. But where do I draw the main 12VDC power supply from going to the magnetic relay?? - the main + terminal of the 12V Battery? I also assume, via one of the oil pressure sensor/switches provided, that signal voltage is only supplied to the magnetic relay (i,e, closing the contacts) with the engine running , so that the current supplied to the heaters, is provided by the Alternator rather than the vehicle batteries?? But there are 3ea, oil pressure sensor/switches/sending units included in this kit. What is the function of these other two? One, oil pressure sensor/switch/sending unit (titled: "Sending Unit") has P/N 1977-5965573, another oil pressure sensor/switch (titled: "Switch,low oil {pressure}) has P/N 1977-MB308B20000, and the third oil pressure sensor switch (titled: "Switch,oil pressure") has P/N 1977-MA308-20009. I wrote the supplier of this kit to the U.S. Govt, "Wheeler Fleet" ,384 Drum Ave. Somerset PA. and got NO response!! I would greatly appreciate any help anyone could provide. Perhaps someone has a truck with this kit installed and can tell me or make a few fotos of how this is all hooked up and if they have experienced any problems with shifting....ONLY....when the Transmission is COLD . Thanks in advance! P.S. I am thinking about installing this kit BECAUSE I have trouble shifting the transmission into nearly ANY gear on both my M920 and the M916 Trucks BUT ONLY WHEN THE OUTSIDE TEMPRETATURE DROPS BELOW SAY about 50-55 degrees F ,--i.e, NO PROBLEMS SHIFTING IN SUMMER even upon initial morning start up... BUT COOL Fall days or early Springtime ---BOTH transmissions do not want to shift into gear! I read all the other Cat 7155 Blog comments posted on Steel Sol. about oiling and pressure reg. etc. AND I AGRREE, I will also try these suggestions. But that I ONLY have these shifting problems when the transmission is COLD leads me to think that perhaps this heater kit could be the long term solution????

 

[Mullaney]

I am in need of some help with the installation of this winterization kit for the Cat 7155 transmission-- control block strip heater kit on my M920 & M916 Trucks. The kit came with 4 pages of diagrams--but only of the included items in the kit --NOT how to install it in the vehicle. I see that the strip heaters are clamped to the transmission control block and that there is a light installed in the cab showing the heating system is ON. However, there is no discription of HOW the system works NOR any instructions exactly how to install this kit . There are various components in the kit: 3X oil pressure sensor/switches, 1X temp. sensor/switch. 1X magnetic relay switch, wiring harness, the strip heater bars with insulation and covers, signal light for the cab, brackets & misc. hardware etc. I assume the magnetic relay is to provide main 12VDC power to the heaters....and I assume one oil pressure sensor/switch provides a 12VDC signal voltage to the magnetic relay to "close" (thereby supplying current to the strip heaters) with the other terminal of the magnetic relay going to a temp sensor mounted on the top of the transmission control block...this I assume is the GROUND for the magnetic relay ....i.e. when the control block is COLD, the temp sensor/switch is "closed " (providing a Ground) and when the control block is warm , this temp sensor switch...breaks the "ground" for the magnetic relay ....thereby opening the magnetic relay contacts---and cutting the power supply to the heaters i.e shutting the heaters off. But where do I draw the main 12VDC power supply from going to the magnetic relay?? - the main + terminal of the 12V Battery? I also assume, via one of the oil pressure sensor/switches provided, that signal voltage is only supplied to the magnetic relay (i,e, closing the contacts) with the engine running , so that the current supplied to the heaters, is provided by the Alternator rather than the vehicle batteries?? But there are 3ea, oil pressure sensor/switches/sending units included in this kit. What is the function of these other two? One, oil pressure sensor/switch/sending unit (titled: "Sending Unit") has P/N 1977-5965573, another oil pressure sensor/switch (titled: "Switch,low oil {pressure}) has P/N 1977-MB308B20000, and the third oil pressure sensor switch (titled: "Switch,oil pressure") has P/N 1977-MA308-20009. I wrote the supplier of this kit to the U.S. Govt, "Wheeler Fleet" ,384 Drum Ave. Somerset PA. and got NO response!! I would greatly appreciate any help anyone could provide. Perhaps someone has a truck with this kit installed and can tell me or make a few fotos of how this is all hooked up and if they have experienced any problems with shifting....ONLY....when the Transmission is COLD . Thanks in advance! P.S. I am thinking about installing this kit BECAUSE I have trouble shifting the transmission into nearly ANY gear on both my M920 and the M916 Trucks BUT ONLY WHEN THE OUTSIDE TEMPRETATURE DROPS BELOW SAY about 50-55 degrees F ,--i.e, NO PROBLEMS SHIFTING IN SUMMER even upon initial morning start up... BUT COOL Fall days or early Springtime ---BOTH transmissions do not want to shift into gear! I read all the other Cat 7155 Blog comments posted on Steel Sol. about oiling and pressure reg. etc. AND I AGRREE, I will also try these suggestions. But that I ONLY have these shifting problems when the transmission is COLD leads me to think that perhaps this heater kit could be the long term solution????

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I know absolutely NOTHING about the winterization kit and its installation. Do know that the 7155 has a real need for clean dry air though. Especially so if it is cold. Ice in the air lines is bad news for sure. Cold slows things down before it freezes and if the air dryer isn't doing its job, the problem just gets worse as the temperature drops...

 

[Floridianson]

Sure you are doing it but thought I would ask. Does doing the running gears warm up help at all. That is where after air pressure is built up Trans. in neutral then push in the side panel air control button and do regular truck warm up.

 

[simp5782]

The system is designed that oil pressure sends power to the transmission heater only when oil pressure is present. The thermostat bolted to the valve body has its own ground at itself and the power comes into it and the leaves it and sends power to the heater units.

The oil switch is there so that the power doesn't get left on and run the battery down after so long

 

[Mark Buller]

Thanks guys..I am doing the normal truck warm up ...leting it idle for sometimes half hour before it will slowly go into gear 6 or 7... then I drive it around in this gear only... for a couple of miles ...then as things start to warm up.... the transmission begins to slowly shift into more gears and the longer I drive ...the more "normal" everything becomes. And after 20-30 minutes of driving , everything is back to normal...shifting into all gears as if it were summer. Yes , of course Ice in the air lines is 100% trouble...but my problems start well before freezing temps.....just a little cool and the tranny does not want to go into gear.

 

[simp5782]

You know that the transmission runs off of oil pressure right? It uses its own oil to engage the front clutch to take off. What oil grade are you using?

 

[Mark Buller]

Hi thanks for your response. I am using what the U.S. Army put in the truck (the truck only has 2,800 miles total since rebuild at Texas RMS in 2007....I assume it is OE-HDO-10 (also because it looks and feels like grade 10 oil)...although a placard on the inside driver door says to use SAE 10W-30...which from my understanding would be even a thicker oil-as it warms up. Which does make sense for good internal transmission lubrication BUT makes no sense concerning the air control block. Iam sure Dextron ATF would be a little too thin except for perhaps Artic conditions. I can find no suggestions to change transmission oil based on ambient air temps. ???

 

[Floridianson]

Hi thanks for your response. I am using what the U.S. Army put in the truck (the truck only has 2,800 miles total since rebuild at Texas RMS in 2007....I assume it is OE-HDO-10 (also because it looks and feels like grade 10 oil)...although a placard on the inside driver door says to use SAE 10W-30...which from my understanding would be even a thicker oil-as it warms up. Which does make sense for good internal transmission lubrication BUT makes no sense concerning the air control block. Iam sure Dextron ATF would be a little too thin except for perhaps Artic conditions. I can find no suggestions to change transmission oil based on ambient air temps. ???

When I did have the 7155 I would have never put in ATF. Artic conditions the heater in your post I assume was used. In the manual for the 7155 it said to help limber up the oil some was to wait for air pressure to built after first start or if you held air pressure overnight enough to keep the button in then push it in after start. No air pressure after start then wait then push in the air control button on the side of the shift box as soon as you can. Then still wait for everything else to warm / limber up engine oil / coolant for your 20 mins. If you are not doing it just try it is all I can say.