[Dez678]

My hyundai 1.6 diesel auto was driving a long as normal yesterday when suddenly it started to judder. It will.only move now when reved well up and will.not move in reverse could some one tell me what could be wrong

[Dazzler]

Welcome Dez678,

Sorry to hear that, but we need a lot more information!

What build year is it? So we can work out what series (FD or GD) I assume it's not series 3 (PD)

Is it a hatch or a wagon (not that it will affect the diagnosis)

What mileage?

Before this happened had you had any other problems with the behaviour of the transmission? E.G. Hesitation when selecting Drive or Reverse.

The transmission has obviously $hit itself, but I'm no mechanic so hard to pinpoint the exact fault without a bit more info.

I'm guessing you are well out of warranty?

[tw2005]

My hyundai 1.6 diesel auto was driving a long as normal yesterday when suddenly it started to judder. It will.only move now when reved well up and will.not move in reverse could some one tell me what could be wrong

Sounds like it could be Valve body failure but you need someone to do some diagnostics. Don't drive if it's that  bad, otherwise you may cook it or destroy entirely.  From memory when the electronics fail, you have manual 2nd, 3rd and reverse, and it's not fun driving it in failsafe.