Allison 4000 temperature sensor

[Fred Cook]

Can someone tell me where the temp sensor is located on my 4000 transmission? I no longer get a temp reading on the dial gauge in the dash and a zero degree reading on the VMS. So…. I’m thinking I may have a bad sensor. Hopefully someone may have more expertise and point me in the right direction.

[Eric Maclean]

Fred
The Allison transmission has it own sensir which is part of the internal wiring harness inside the transmission, if that sensor fails there will be a transmission code set .
However the dash gauge is not run from the transmission sensor,it has its own sending unit which depending on the year and model of the coach is usually located in the transmission cooler lines near the cooler.
The sending unit will be screwed into a fitting near either the cooler or the transmission and will have a single wire connected.
You may also want to check the connections at the back of the gauge as they do get loose with time.
The gauge under normal conditions does not read very high as the trans temps run in the 140* to 160* range my unit takes nearly half an hour of driving to show on the gauge.
You should be able to read the trans temps from the Aladin or equivalent which is straight from the serial stream data from the transmission/ engine interface via the J1939 network.
Use that to compare your readings remembering  the aladin data will be far more accurate than the dash gauge.

Hope this helps
Eric

[Fred Cook]

Thanks Eric, appreciate your input very much. My SilverLeaf VMS was is also not working properly as the screen is practically unreadable and no parts or replacement is available. So I ordered a ScabGuage D hoping it will provide all readings including the transmission temperature.

[Paul Meehan]

Fred, when we had our 2001 Patriot our Silverleaf monitor began pixeling really bad and at time the gauge arrows did not consistently react to the coaches operation.  I read about Silverleaf's VMSPC to 6 or 9 pin diagnostic port to provide engine and transmission monitoring.  A competing product is called Bluefire (https://bluefire-llc.com/store/motorhomes) is what I went with.  I obtained a J1708 (6-pin) adapter which plugged into the diagnostic port under the dash and used the free software on a Lenovo laptop (various tablets can be used as well) to build and display a dashboard of various data points.  You may have a J1939 (9 pin diagnostic port.)

You might want to read about both options.  All I had to buy was the J1708 Dongle adapter which now cost $230.  I had the laptop and a tablet to fall back on if needed.  The Silverleaf solution was more expensive and required a harness and software.  Not sure what devices can be used to display your dashboard.

Silverleaf's product has come a long way since I first looked at them.

I know of one fellow Beaver member who tried the Bluefire solution in a Tiffin coach and ran into interference with the Bluetooth transfer of data and has since stopped using the BlueFire solution.  I did not experience any problems.

Attachments are the diagnostic port and a sample dashboard.

[Fred Cook]

Paul, thanks for the great info. Was the $230 cost for the J1708 Dongle adapter a typo error? Also, do you think the ScanGauge D would work just as well?  Fred

[Paul Meehan]

It looks as if the 6 pin adapter is no longer available.  The website instructs you to obtain a 9 pin to 6 pin cable and a 9 pin adapter.  The adapter is $230 not sure how much the cable is.  You could call them to find out what you need to make the conversion.  They used to be very helpful.

I downloaded the software and a few sample dashboards from other forums.  I built my own dashboard to determine how easy it would be.  Once I completed the build I bought the 6 pin adapter.  It was good experience.

[Bill Borden]

Hi Fred,

Our 2000 PAT Silverleaf display had been fading to the point of being unreadable.  I changed over to the Silverleaf VMSpc.

Using an Acer 3-way convertible type laptop, with Win 10.  I connected to the existing harness with a unit from Silverleaf that had a USB output.  Ran it up to the overhead, complete with a 12 v power supply for the PC.  I love it, I have designed my own display and at a glance can see the status of every bit of information, all at once.  Quite a bit more information than the old display.  Silverleaf has a program that is easy to use and works great with the CAT information datalink. It's free to use.

I posted some information a few years back about the change, here is a link, http://beaveramb.org/forum/index.php/topic,4100.msg31491.html#msg31491

Attached is a picture of the screen placement, I have customized the display a few times since then, and included is a screenshot with the current layout.

Good luck with your upgrade.

[Paul Meehan]

That is awesome Bill!  Does the VMSpc solution provide audible alarms if user defined parameters are reached?
Great job!

[Fred Cook]

Really appreciate your input but now I have another problem…. the J1708 connector under the dash resistors no power but my rear one has 12 volts. Is there a fuse to the front data portal and where would it be located?

[Bill Borden]

Fred,

Have you checked the connections and the ground for corrosion?  The Silverleaf does have a power input from the Ignition key switch, there should be an inline fuse.  I would start there, and also check the tech port back in the engine filter bay, to see if you have the power there.

Paul,

Thank you, I like having better access & an easy-to-read display of the information that I want to monitor.

As to the alarms, each gauge has the ability to change color at a preset level.  So if the Intake Manifold Temperature goes past a set point it turns Red.  But no audible alarm.  That would be nice, I will ask Silverleaf.  Newer motors than my 2000 C12, have more sensors to access, and they use a newer version of the software.  It may have audible alarms.

There is an engine code page also, so you can check for codes.  A maintenance minder.  And I really like the ability to see other things such as speed, engine hours, etc.

[Fred Cook]

OK, we can put this on to bed. I found the problem….. it was a faulty ground wire. I got the ScanGaude D up and running.  Thanks again for your willingness to help. Fred.