A family member of mine worked on the development of this project at Laycocks Engineering (of overdrive gearboxes fame). Unfortunately I don't know much more about it as the family member now lives overseas.
I think the later Type 3 (there are two types of type 3 gearbox) was the only one fitted to a pinto and as far as I know it was only on the 1.6litre pinto.
I wouldn't fit a type 3 behind a 2litre pinto. Not an overly strong gearbox. Certainly not as strong as a Type E. In my opinion if you're going to fit a type E jut fit a type 9 instead.
I've got a complete diff in nice condition with genuine Ford CWP, nice gear teeth, no rust in the gear teeth etc. £275. I can package if you send your own courier.
This is to fit a 1100/1300 rear bowl xflow engine - my very original mk2 1300 escort (which has a 711m 1300 block) came with one and all of the other 1100/1300 engines I bought came with one too. Numbers crossover - it doesn't mean it's only for a vehicle designated with "751" - for example a Lotus twincam has an anglia 105e dipstick.
If ou have the standard 3 rail cortina box you'll need 75/90 mineral GL4 oil (do not use GL5), and for a standard rear axle an EP80/90 hypoid GL5 is what you need. I normally use Comma oils for axle and gearbox.
Backlash is 0.005-0.007" - if it's tighter than that there's an issue, and the bottom and top limit need to be quite close so you wouldn't want 0.005" at the tightest spot and 0.015" at the loosest - you'd want tightest ideally at 0.005" and loosest ideally no more than 0.007".
Love the spanners in the boot comment!
Sounds a bit ominous! Is there corresponding corrosion on the pinion head over-run side? I wonder if some moisture has got in and sat on top of the oil and caused those marks where the teeth have have contacting?
Has the car been sat over-winter?
Let's hope you can sort it - keep us posted.
BTW - I've seen a 3.3 built up into a diff and they look OK but just aren't quite as good as a genuine Ford one.
I'm not sure if you took what I said the wrong way, or whether I've mistaken your intent? Didn't mean it shouldn't be taken to pieces, I meant that your missus just kept driving it and could somehow not be bothered by it! It's almost a blessing to be that way!
I rebuild Ford diffs so I know when they're even slightly noisy there's a problem