I’ve read a few threads on forums about vacuum solenoids and sensors causing the green light to flash, but my truck drives absolutely fine until after around 45minutes, when it seems to develop wind up (sluggish, noise like something is dragging on a tyre & when you stop there’s a release of tension in the transmission with a palpable clunk) and then the green flashing light comes on. Bizarrely it then drives ok but with maybe one or two episodes of wind up thereafter.

I’ve tried reversing whilst turning the wheels left & right when it’s come on but to no avail.

About 2 years ago I had the transmission (diff & gearbox) oil changed throughout. It drove amazingly after that! But I’ve recently developed an oil leak. With the two, I was convinced this must be the transfer box oil being low causing something to bind when hot, but going under the truck the transfer box is bone dry and the oil seems to be concentrated on the left chassis member towards the rear, possibly coming from a pipe??

I love this truck, want to do a few things to make it better but need to get this fixed before I invest in other areas. Any ideas on how to progress this would be very gratefully received. I’m gutted there’s no Haynes manual fir the K74.

Thanks All

Ian

Hello mate
are you using 4WD when the 'wind up' happens or 2WD ?
the system in these trucks only allows you to use 4WD on loose or slippery surfaces
using 4WD on hard surfaces will get expensive very quickly as diff lock up is usually the first damage

your palpable clunk sounds to me like the front diff actuator isn't disengaging properly usually when you come to a complete stop
under the front of the truck on the front axle there is a little rubber bellow type of thing that contains a rod that slides in and out to engage the front wheels
sometimes this can stick so pull the rubber back and get liberal with some WD40 type of stuff and see if that helps