Help please - Whilst checking the geabox oil level on my Felicia 1.3 MPI (1998) the drive gear and associated shaft (about 3" in length) fell out of the speedometer drive assembly and into the final drive housing!

I'm a failrly competent mechanic but can't find any schematics for this gearbox. A (gearbox in car) visual inspection suggests that the final drive housing is completely integral with the gearbox housing. I'm quite prepared to remove the gearbox but does anyone have any info on how difficult it is to get access into the final drive housing to remove the above components (and if any special tools are required)?.

Thanks in anticipation.......

Well I took the plunge and opened it up. If you tackle a job like this yourself be ready to catch the reverse gear shaft, reverse gear, a washer, an o-ring and a magnet. Apart from that and two pairs of hands to reassemble the gearbox it was straightforward.