I agree. If you want to cast a new gearbox, why not design it so it fits standard components? You could design it around standard bearings, standard shift forks, standard gears etc. Standard meaning more plentiful than parts for a 16+ year old car... There are tons of gear options for standard raci...

Drew, At this point I feel that to properly support higher power and torque outputs that the Saab 900 gearbox should use spur gears and not helical gears. This might very well prevent having to cast or machine a new case. I'm looking into the possibility of making involute spur gears with a hob on u...

Been doing a lot of reading. Purchased a book called: How To Rebuild And Modify Your Manual Transmission by Robert Bowen. Published by Motorbooks. ISBN-13:978-0-7603-2047-1. Feel free to agree or disagree with the following statements taken from this book: Page 20: "There are a few trade-offs w...

If Drew is correct and it's the splined output shaft flexing that often causes gears to break in the 900 gearbox, wouldn't spur gears/straight cut gears/dog cut gears (how did we end up with so many names for spur gears?) tolerate the misalignment much better than helical gears? In addition wouldn't...

In the older trans thread on this site someone posted up photos of a bunch of Jørgen's stuff, the 4-chain primaries have drive sprockets with 4 rows of teeth, it's not just an additional sprocket attached to the 3-chain hubs, though that might be the easiest thing for you to fab up. Drew The old th...

Reading through old threads and just found this. Should compliment the Saab 900 Service Manual For the 4:1 Manual Transmission 1979-88 I just got my hands on yesterday. Thanks for posting this!

In the older trans thread on this site someone posted up photos of a bunch of Jørgen's stuff, the 4-chain primaries have drive sprockets with 4 rows of teeth, it's not just an additional sprocket attached to the 3-chain hubs, though that might be the easiest thing for you to fab up. Drew I'll go lo...

I'm glad that you are persuing this. Drew I can use all the help I can get. What I learn I'll share. However, I highly suggest you pick up the cheapest extra C900 box you can get your hands on, broken or not (unless you have one already) and tear it down (unless you have done that already). Drew I ...

As I said....anything is possible and it all comes down to how much time, energy, and money you have. A lot of it looks to me like having the connections to those in countries outside of the U.S. who know where to get the parts. Also Jorgen in Sweden is a good resource for knowledge on strong gear ...

As I said....anything is possible and it all comes down to how much time, energy, and money you have. A lot of it looks to me like having the connections to those in countries outside of the U.S. who know where to get the parts. Also Jorgen in Sweden is a good resource for knowledge on strong gear ...

Eriksson Industries in CT used to make a "huge pinion housing" for pre '89 boxes (4 and 5spd). It was an enlarged housing and a "huge" pinion bearing. The pinion bearing was larger than the bearing that came with the 89+ boxes. Apparently this kit is no longer available. However...

Jordan, based on the very limited information I have, I'm leaning toward building a 4 speed using the Chillcast 870423 case and using the biggest gears I can find as well as any significantly beefed up components I can find. Has anyone else taken this approach and posted about the results? Still hav...

anything is possible with enough $$$$. Its just that most of us don't have a spare $50,000 laying around to pay for the material, machine time, and development work to build said gearbox. Knowledge, experience and creativity can often be a much better answer than throwing "$$$$" at the pr...

Would you say that case flex is the biggest problem? If so, why hasn't someone thought about designing a new sand casting for a case that's more rigid? Where I use to work we machined numerous prototype sand castings for these guys: http://www.mendeolatransaxles.com/homepage.php Perhaps short runs m...

I'd like to put together a gearbox capable of handling 350 to 400hp that doesn't have to be treated like a baby. My application is street only. A few questions: 1. Is this possible? 2. Am I better off creating a 4 speed than a 5 speed? 3. Is the 4-speed Chillcast box 870423 still the strongest case ...