Intermittent rattling and 4WD Low won't enegage.

Hi All..

My old faithful 2004 VVT has developed an intermittent knocking/rattling under acceleration and 4WD Low won't engage - just three beeps. There's 100,000 on the clock. I haven't used 4WD low for a year or so because I haven't needed to with the mild winters.
It started a couple of weeks ago and occasionally I got the three beeps without touching any selector buttons. 4WD High is OK.
I've just had it serviced and it will sail through the next MOT if I change a couple of brake pipes, but I don't want to spend a fortune on repairs due to the age of the JImny. I'd sooner keep it for spares and get another one. In the past I've had trouble engaging and disengaging Low. Maybe something's siezed?

Anybody any ideas.

Could be the actuator seized, or a broken wire from one of the switches on the transfer box.

The rattling, check the heatshield on the catalyst under the passengers feet, the gearbox rear mount (if it is gone you can lift the gearbox right at the back from underneath ) bushes/bolts in the trailing arms, the panhard rod to rear axle, and propshaft UJ.

If it is a groaning sound, check the crankshaft pulley outer isn't de-laminating.

100,000 miles is nothing, most of ours have done at least that

Hi...
Sorry to take so long in replying and thanks for the advice.

I've now passed the old Jimny on to a mate to use as a restoration/off roading project.

Cheers

Malc