Factory Diff Lock Pump Replacment

[cookie9]

ok, seems the harrop is the only option for a dead OEM locker.


I need to check my pump as think that is my probelm also, if its only few hundred makes sense to replace the faulty pump..


cheers

[old Jack]

ok, seems the harrop is the only option for a dead OEM locker.

I need to check my pump as think that is my probelm also, if its only few hundred makes sense to replace the faulty pump..

cheers

Sorry Cookie, I misunderstood your question.

The PB PC Challenger that is fitted with a factory diff lock has a different CW&P gears, different bearing sizes, different axle lengths and different axle spline counts to the PB /PC Challengers that do not have a factory diff lock. I am reasonably sure the aftermarket diff locks from Harrop, ARB and TJM only fit the Challengers without the factory diff lock.

It seems the cheapest option is a $300 pump from Partsque or a secondhand pump from a wrecker.

OJ.

[datrat]

It seems the cheapest option is a $300 pump from Partsque or a secondhand pump from a wrecker.

OJ.[/QUOTE]

Good prices on that website.
The suzuki pump p/n 2794065D03 is the cheapest $206.38 aud
The cheapest mitsubishi p/n 3590A011 is $442.04 AUD ($300US)
I'm thinking to get the suzuki pump to save all the messing around.
Im also thinking of relocating the pump and breathers into the rear of wagon near the jack.
Has anyone done this?

[cookie9]

how did you go?


got mine heading in for service next week and they are having a look at the pump/diff to see if they can figure out whats up..

[cookie9]

mechanic just looked at the diff, the pump is working fine so he thinks something internal that is not letting it fully engage.. Further investigations required...

[datrat]

how did you go?


got mine heading in for service next week and they are having a look at the pump/diff to see if they can figure out whats up..

Well my diff is locking no problems now. I bought the suzuki pump online. I changed the bracket over to the challenger one. Also the plug and wiring is different. The suzuki uses 3 wires and the mitsubishi uses two jut an earth and positive. The 3rd wire (pink) is just left and not connected.
I have had the replacement pump for about 3 week but only got time today to fit it up. At a later date I will look at relocating the pump in to the rear quarter panel near the jack.

[MartinDanger]

Thanks for the info

Thanks for sharing the info and photos about the pump. I found it really helpful when diagnosing my own diff lock issues.
My issues are weird. Took the pump apart, checked everything and it seems to work. The pressure sensor is a diaphragm type that activates a micro switch. That cuts the power to the pump but not the solenoid. The solenoid is the pressure relief valve that closes and holds pressure when powered. When power is cut (when the diff lock off switch is pressed), it opens and releases pressure which is what disengages the diff lock.

I powered the pump with a battery and it locked the diff. But when I plugged it back in to the vehicle power supply, it activated the pump, but not the diff lock. And in both scenarios the pump would sometimes run for 10 seconds or so and then stop, other times it would run and stop and run and stop over and over.

[old Jack]

Sounds like a dodgy electrical connection.
If you can insert the multimeter probes from the back of the plug and monitor the voltage.

OJ.

[Kingbrown]

In addition to what OJ says, take a close look at the small black knobby item that's on the end of the tube for suction and vent on the pump.

It's not unheard of for the vent to get blocked with mud and crud.

(personally, I re-routed that line to inside the cab and put a decent filter on it).

[MartinDanger]

Further investigations

I’m getting battery voltage at the plug when the ignition is on (engine not running) and the diff lock switch is on (while also in 4Hlc)so that seems right. I’ve tried to clean up the terminals with some emery paper but there wasn’t much room so can’t be certain it helped much.

Oddly, when I locked the diff using a hand pump, the diff lock light didn’t light up.

I’ll check the end cap on the inlet air pipe next.

I agree that it’s not the best place for an air inlet though. Imagine pressing the diff lock switch and activating the pump when submerged! The pump would suck water in, wouldn’t it? And then short out as the internal wires and PCB are there without protection.

Thanks guys!

[MartinDanger]

ROFL - Forgot the first lesson of fixing anything

What's the first lesson?

1. Determine the problem that needs fixing - which includes confirming that what you have been told is the problem, is actually the problem.

I thought the diff lock didn't work because the diff lock light kept flashing after pressing the diff lock request switch (I call it a request switch because it sends a request that the ECU then decides whether to grant). I couldn't test it easily with the gear that I had at home unfortunately because you need all 4 wheels off the ground (all 3 could work too but risky if ATC doesn't disengage).

After taking the pump apart twice and knowing it worked, I had this frustrated feeling in me that the diff lock should work. So I went for a drive, found a ditch, got crossed up nicely with both wheels in the air and no forward progress. Sent the diff lock request, was told to please wait (light flashing) and then started to move. Opened the door to look at the rear wheel (driver's side rear suspension was fully compressed) to see it slowly spinning despite all that load and its opposite in the air. A bit more throttle and it got out.

So now, after remembering that lesson (a little too late!), I'm going to follow the rules - check the easiest thing first and work backwards. That is, check the diff lock sensor is reading the right voltage , then the wiring from the sensor before anything more complicated.

Hilarious!