Technical Panda 2013 4x4 transmission judder

[348azeus]

I’m no expert on the 4x4 system so having read various threads I’m just trying to confirm my suspicion of having damaged my transfer box.
I’ve got a 2013 model and I stupidly left the ELD button on driving out of my snow covered field and then proceeded to drive around 40 miles on tarmac. I’ve now got a bad judder on tight left hand bends especially at slower speed. I’ve changed the prop as my centre bearing had fallen apart but this hasn’t helped so I fear I may have an internal transfer box problem. The panda is a 1.3 and has covered around 45,000 miles.
I’ve eliminated any other suspension/ cv joint problems as everything is fine so I’m left with the gearbox and transfer box. Drives fine on a straight road but as soon as I do a series of tight left handers the problem is evident. Curiously if I reverse in a straight line for a short distance then it seems to unwind itself but this doesn’t last very long. Any thoughts and does anybody have any manuals on rebuilding the transfer box ?

 

[Herts Hillhopper]

Sorry - I only just saw you left a private message about this.

It won’t be the transfer box (by which I assume you mean between the gearbox and the propshaft at the front of the car) as that is always connected and the propshaft always turns, even in 2 wheel drive mode.

The engagement of 4WD happens at the rear of the propshaft via a unit between it and the rear diff.

In there, a solenoid ‘does something’ (we’ve never really got the bottom of exactly what) to
engage the rear drive. That happens completely automatically if the ELD switch is off or the Cross selector dial is in ‘on road’ mode. But it can also be forced by pressing the button/turning the dial. (Rarely, if ever, will you need to select that mode - unless drive is lost as a result of one wheel spinning free, usually because it’s off the ground).

It sounds like the solenoid may not have disengaged itself - ie it’s stuck in the ‘engage 4x4 position’. I believe (but have never actually tried) the solenoid unit can be unbolted and its operation checked.

Hope this gets you nearer a solution

Pete

 

[348azeus]

Hi thanks for the reply. I will check the solenoid. I have found a lot of reading material on the ELD which I will need to get my head around. When I find the cause of the problem I will report back.

 

[Herts Hillhopper]

Worth noting that ELD is separate to 4 wheel drive, and I don’t believe is the cause of your issue. Confusingly Fiat label the switch ELD, but that’s not its main function, (which is to force 4WD. Pressing it also changes the throttle map and turns off parts of the traction control/ESC system)

The ELD is something different. It doesn’t lock any differentials at all (despite its name!). Instead, if the button/rotary control is set to let it operate, it allows the ABS sensors to detect if one wheel on ‘an axle’ is stationary and the other spinning (typically if one rear wheel comes up off the ground on rough terrain it will spin freely and the wheel on the ground stops getting power, owing to the way differentials work). The system applies the brake to the spinning wheel, which simulates the effect of locking the diff and allows the other wheel to be powered.

That is demonstrated in tests like this one, where without ELD drive to the rear wheels would effectively be lost

It doesn’t lock any differentials between front and rear either (in the way a pre 2016 Defender does) — because there is no centre differential there. Hence the risk of wind-up. (This is true of many larger 4x4s too, eg the Nissan Navara, or the Isuzu D-Max - both of which are normally 2 wheel drive and have a 4WD system that should only be used off road owing to the lack of a central differential)

 

[348azeus]

Thanks for this. I’ve been reading some of the things on e learn which you have explained in a far simpler way. I will check the solenoid but the suggestion is if it was anything to do with the ELD it would probably have thrown up some warning messages and codes. I am starting to think I may actually have a mechanical issue with the front diff.