I’m currently rebuilding a 4sp manual box too.
If you want a good schematic of the box, Niemoller or SLS show a pretty decent one.
If you’ve separated the bell housing, make sure you keep the round shims that fill the space between the bearing race and the bell housing. They are very hard to obtain, but can found, at least I’ve found them in 0.2mm increments. Of course I need 0.95mm to set the input shaft end float, so 4 shims and a liberal application of three bond to seal the bell housing might just work 🤞🏻
In regards to separating the input shaft from the gear cluster, at least I think that’s what you’re asking?
There is a snap ring holding the front bearing on to the shaft. Take the snap ring off, bearing and any other oil slingers or shims that are there.
4th gear is part of the input shaft and has a needle roller bearing in the middle of between the gearset and the inner part of the 4th gear/input shaft.
You need to remove all the case bearings to get both the shafts out. This will involve removing the output flange and its nut (A special tool is required or needs to be fabricated). This holds the speedo drive and 1st and 2nd gear on the gearset. I would refit the input shaft without the bearing and slide the clutch release housing over it and stand it up in a vice with soft jaws or rags and timber. This stops 1st gear and in particular 2nd gear from sliding off the shaft, otherwise there’s a chance the split needle rollers will go everywhere.
It’s not particularly complex, just heavy, ensure you take plenty of photos and notes. I would mark everything with a white paint marker, even the bolts.
Happy to try and assist. Pretty sure there’s a good write up on here and it may be in the technical manual, I found a couple of posts which I should have bookmarked. I’ll try and find them.
Doug
