tuscon 4wd front diff locked up

[Calzoe68]

Hi all
Just had my full set of injectors chamged after a month in the garage as supply issues .
The next day i was driving down the motorway then had a loss of power and a rattling noise coming from the engine .
Pulled over lifted bonnet small amount of smoke steam came out .
Got back in the car car starts no error lights engine revs sounds smooth but for some reason the front wheels wont turn rears will spin as its a 4wd 2016 .
It feels like when you leave a handbrake on the rears but its the front wheels .
think it maybe the fornt differential locked or siezed does anyone know if its an easy repair or a video link to show you how to change the front diff as i can find nothing online .

thanks
alan

[PhilHornby]

The "small amount of smoke steam" seems incongruous with the rest of the symptoms. Where did it come from

Assuming you're correct and the rear wheels are being driven and the front ones not, I would work backwards from each front wheel and see what is still connected and what isn't. What is seized and what still rotates?
Maybe it's brake caliper related? - as in, seized-on. Failing that, I would think it would be far more likely to be a CV joint than the diff. It could even be a seized wheel bearing, though they seem to come loose, rather than seize. Perhaps you ran over something that got wound round the axle?

I've never had cause to tackle an issue like this, despite having had several vehicles that did over 100K miles. I did once cause the viscous couplings of a 4W-Steer Honda Prelude to fail, which caused instant loss of drive. Fortunately, I'd only borrowed it, so it wasn't my problem