Im planning to rebuild my S40 and i expect it to be very dirty inside.

What is recommended to clean both the tranmission and clutch housing inner side, aswell as the inners parts gears/shafts/hubs etc before reassembly ?
Ive read that aluminium is sensivite to acid.

Thanks

 

I didn't clean it out, it will just be a little residue of gear lube. I did clean the magnet with brake cleaner (non-chlorinated) and a rag. And every seal housing got cleaned with brake cleaner.

I use brake cleaner as it's supposed to evaporate residue free. Anything else, I was concerned would leave a residue that may act on the fresh fluid to some degree. I wanted to avoid having to do a dump and fill shortly after putting fresh fluid in after rebuild.

 

Oh one other tip I can share.

Take pics before disassembly and each piece you take off. It's so easy to get a gear up side down or a thrust washer etc. If you take a good picture of each gear before and just after removal for orientation, it should make it easier to put it back together properly.

 

Inside the case will be clean - just wipe out with a rag.

The bellhousing will be nasty. Clean the bulk of the sludge and grime off with rags, water, etc. I use a small brush (toothbrush size, but with stiffer bristles...they're cheap on Amazon) and LA's Totally Awesome Carpet Cleaner from Dollar Tree (it's $0.99 a bottle and it's a great degreaser/cleaner). Brake parts cleaner works well, but it evaporates too quickly so you'll end up going through a ton of it.

For chalky areas on the outside of the case, a media blast is best, but if you don't have access to that, a wire wheel on a drill works wonders, but it's difficult to get in some of the tighter areas with it.