I have an opportunity to grab this car very cheap. He says it slips in first gear.
The car is brilliant otherwise. What am I looking at here?

 

The worst case would be the clip retaining ring in the A clutch drum will break and bits of metal will float around the gearbox. You'll also be in limp mode. That would be characterised by a refusal to engage gear untill eventually it finds one it can, then because it's revving so much it bangs into it and limps.
Usually caused by the main pressure control valve wearing and causing pressure spikes. There's plenty info on it that explains better.

I suppose the best case would be to not drive the car (get it trailered, don't risk further damage), then get the valve body inspected and replaced or fitted with an oversized valve (after reaming the bore) if required. That's what I am in the process of doing now on a spare 5HP24, having had it fail and break the A drum. However, you won't be sure the A drum is not already weakened so you should probably inspect it too or at the very least drop the sump and see if there are bits of metal floating or stuck to the magnets.

If you can take your time over it and are mechanically competent it won't be a problem and you could end up with something of really good value, but if you're after a quick fix at a bargain price, this won't be it.

 

Nothing more expensive than a cheap luxury car ...........

If this is a one owner garage kept 60k all records queen and the owner just had some bad luck with the trans going out ..........and this event has changed his mind about keeping the car -- then I'm all in.

Otherwise it is just an old luxury car with a bad transmission with any number of other problems.


The x308 can be a great car ---- when purchased correctly.

 

Caveat emptor.....but as the guys have already said, get it checked out and it may not be as bad as you think.
Repaired correctly, you could have a real bargain ;o)

 

Worst case, $4,000 for a rebuild at a decent shop. How cheap is 'cheap'? I got mine free from my elderly father with full maintenance records and the dead tranny - he was tired of spending money on it and about to quit driving, due to age, anyway.

Fortunately for me, the spending was over after fixing the transmission for $4k. It's been pretty much trouble free since.