Search results

Ok, so when you turn on the main switch, do you get a low oil pressure light on the dash? Do you also get relay K26(neutral) and K11(alt excite) relays energizing? You need these 3 things to enable the start circuit. The trans controller powers K26 when in neutral. K26 in turn provides...

I would start with an oil stiction additive. the heui injectors use electric spool valves with close tolerances. Engine Oil quality is important. The black smoke is probsbly the spools not closing cleanly and causing the injectors to dump extra fuel. Diesels like to be warm and loaded, so I...

Well that sounds like a couple of things have failed, or else a hack job is in play here. Plumbed properly there is a air operated control valve on the inboard end of the primary and secondary air tanks that feeds the air to the AOP control pushbutton valve at the hydraulic control panel. When...

Yes the codes are in the manuals, but a better resource is the allison MD3060/3070 troubleshooting guide. Google TS2470EN and you will find places to download it like this https://www.manualslib.com/manual/1354071/Allison-Md-3060.html

You need to read out the fault codes in the transmission. Press up and down arrows at tge same time. There are 5 memory positions D1-D5. It will flash D1 ?? ??(2 sets of numbers). Write the numbers down. Note if the mode light is lit. Press the mode button to step thru the 5 memory...

Yea, not a big fan of the MMDC. Too many eggs in one basket...

Well maybe your TPS has issues. It is a center tapped variable resistor, so with an ohm meter hooked to the wiper connection and either of the other 2 connections you should be able to see a smooth resistance change from idle to full pedal position. Any sudden changes in resistance the...

No. The trans controller uses the Throttle Position Sensor(TPS is on top of engine) to provide that information To help steer upshifts and downshifts. it is easy to re-calibrate it, but you want to insure that the pedal first can rotate the governor input(on top of governor) all the way...

Yea that was just that outer solenoid cover. It’s only purpose is to allow for a fitting to vent to the outside. You could remove it and the unit would vent the control air into the cab, the same as is pictured above. They did that on the A1R(at least on the 6X) as they used all the floor...

The PCU uses pilot operated valving. The solenoids control a small amount of air to shift the valve cores in the manifold. So you have seals in the solenoid valve and seals in the core. It could be a seal on a solenoid valve, or the seals on the control core are leaking a little…

No that vent should not be venting until the control solenoid is released… yes the PCU can be disassembled to access the valve cores. They seal with Orings and I believe Superman has spare valve cores…

Have you checked your axle vents? An axle seal will vent air into the axles which will escape thru the axle vent…

Well if the pressure is dropping, then you have a leak:) I think the controller pauses and looks for this pressure stability as a way to diagnose leaks. With control closed and a shot of air to pressurize the system it should be able to set there all day. For a given size hole, the greater the...

I believe It is normal, at least the two I have played with now do it also Even after new valve cores. The supply does(should) not leak when control is de-energized. The solenoid valves in the PCU are pilot actuated and they may be plumbed to deliberately interact this way. (Would alert you to...

Which mirrors did you go with?

I would think it is supposed to accurately reflect switch state, so either the controller is mis-reading the switch circuit or there is a problem with the switch circuit causing it. I would ring out that circuit really well. An ohm meter will tell you if you have a good circuit by jumpering...

but it continues to short cycle with the switch unplugged? Either the switch sense circuit is not working(bad controller) or perhaps there is a low resistance path in the wiring back to the switch… The tester gives you switch state to see if it is cycling properly with manual operation and...

Ok, on the A1 they tapped off brake switch power directly to feed the trailer plug, which bypasses all the other wiring. It is the same brake power that activates K10 When you step on the pedal. One of the reasons I like to concentrate on one problem when there are multiples is that in fixing...

Thats weird. Just to clarify, pressure switch(wet tank) or pressure sensor(on PCU)? If the switch circuit was shorted somewhere along the path from controller connector to wet tank. That would lie to the controller and it would allow it to try and function. The wet tank switch tells the...

What do the primary and secondary brake gauges read when the dryer purges? It should be 125PSI, and the wet tank switch should close above 117… you should be able to measure this closure between two of the 3 pins on the pressure switch connector. Two of those codes you listed indicate a bad...