Gearbox fault, special programmes off

Shawser1203 said:

View attachment 208596

Click to expand...

Yes, and you have 166 ohms.

OK sussed it now. Never noticed the pin numbers on back. Rechecked and its 0ohms.

If you’re sure you were measuring between pins 9 & 12 (slate & green coloured wires respectively) and you’re getting a reading below 0.2Ω then you next need to measure the resistance between the two terminals on the solenoid itself, to see if the short is in the wiring or if it’s the solenoid that’s the problem.



Phil

Yeh defo the correct wires. So the plug that goes onto the motor. Check the connection on the motor itself. If its 0 ohms, then its the motor that's the problem?

Just for the avoidance of any doubt, we’re talking about this solenoid, not the shift motor:



Out of interest, I just checked one and it measured 1.2Ω



Phil

Yeh that's the one I'm testing. Took off connector and tested the contact pins. Still 0 ohms.

Oh well. Looking on the bright side, it’s easier to replace the solenoid than the wiring loom. Land Rover’s list price for the solenoid is around £110, but if you Google the part number IGF500011 you can probably get a better deal on-line.

Do you have access to a diagnostic kit with the capability of energising the solenoid for removal/replacement and for re-calibrating the shift motor afterwards?

Phil

I know a guy with a snap on diagnostic tool, but not sure if it can do it. Does a lot of oil come out when solenoid is taken off the case.

Never tried it, but I guess some will come out because it’s pretty low down. The total capacity of the transfer box is only 1.5 litres though, so it won’t be too much! The workshop manual tells you to drain the fluid first before removing the solenoid and adds “some fluid spillage is inevitable”.

Thinking about it, the solenoid simply moves the shift fork up and down which selects whether the shift motor operates the clutch or the range-change mechanism. Maybe, therefore, calibration isn’t necessary afterwards?

I’ll connect my solenoid up to a power supply to see what it needs to energise it.

Phil

Cheers lad. You're a hero.

Thinking some more about this, the solenoid is simply an ‘on or off’ device that moves the shift fork to one of two positions. This, in turn, moves the shifting sleeve so that the dogs on the sleeve either connect the motor shaft to the clutch-engagement mechanism at one end (solenoid on) or to the range-change mechanism at the other (solenoid off). The shift motor then rotates the motor shaft to operate whichever of the two mechanisms is engaged by the solenoid.

Normal operating mode is with the solenoid energised, so that the shift motor operates the clutch and therefore torque biasing between the front and rear wheels is always available (including completely locked) whenever the system senses that it is needed. In the event of an electrical failure the transfer box will therefore default to range-change mode and the clutch will be open so the centre diff. cannot be locked or the torque biased.

Because of its simple ‘on or off’ nature I don’t think it’s therefore necessary to run the recalibration programme if just the solenoid is replaced. I can see why recalibration is required if the shift motor, controller, position sensor or the transfer box itself are replaced, but not the solenoid.

I applied a power supply to the terminals of a solenoid and, at 12V, it needed a current greater than 3.5A before the solenoid plunger even began to move. My power supply is limited to 5A and I don’t know what the full power requirement is to extend the plunger fully but it’s a fair old current that is continuously needed to keep it energised.

If the Snap-On tool isn’t able to energise the solenoid for you, I guess you’ll have to decide whether to risk cobbling together some kind of temporary power supply to keep the solenoid plunger extended while you remove/engage the plastic T-piece into the shift fork, or find somewhere that has the necessary diagnostic kit to do the job for you? Hmmm, tricky.





Phil

Thanks for that info. There's a company up here in Aberdeen that will do it. They are ex land rover mechanics and have a great reputation. I'll call them on Monday and see what they say. What oil would you recommend for the transfer case?

Use the proper stuff – Shell TF 0753 (Land Rover part no. IYK 500010) – because it’s the only way to guarantee that you have the right friction modifier pack for correct operation of the centre diff. clutch. It’s stupidly expensive (£25-£30/litre), but you don’t need much.

Phil