I have just pulled the bell housing off my stumpy and CA boxes and run into this problem: the secondary shaft bearing is smaller than the CA bearing. So the hole in the bellhousing is too big (see: picture) I have been told that i need to pull the shaft out in order to get the bearing pressed off.

Q1. Is that what everyone else thats done this has had to do?

Q2. If i have to pull the gears apart can i swap all the CA g.box gearing and use the stumpy changing mechanism still?

Straight swap, no changing of the gearbox's internals is required. The Stump adapter plate mounts up to the CA bellhousing (or you use the CA adapter plate (you'll figure it out)) That way it all seats in perfect and mounts up fine
Cheers
Damo

Thats why my first stumpy gearbox broke the reputable company that sold me my engine and box in giraween kept the stock bearing and just bolted it togther !!!! Not a big job to fit a biger bearing . i dont know about changing gears I highly doubt iut as the S13 box has sligtly difernt type of gears.
Cheers Andrew

I have the bearing replaced but in the process the dude at the gearbox and diff shop damaged my gears. (I have posted a pic in the photo albumn to show the damage: picture). Does anyone think this will be a major problem? They didn't charge me for the 25 minute job but should i go back and have a chat?

This string has made me a little nervous because when I put my CA bellhousing on the stumpy box I didn't notice any problems with bearing sizes. When you make the swap do all the boxes have the same problem as Jack's or do they usually fit properly? Mine seemed to but maybe I missed it?

Bye looking at the picture I would say there will be a bit of gearbox noise not heaps though. Only one way to find out I spose.
What sort of power will you be putting through it?? I have broken a few teeth off before and it still drove just made a terrible noise in 3rd.
If you want you can gets gears fixed they weld a bit on and remachine it. My Grand father inlaw (cluey old prick ) has welded gear teeth up and filed them up no noise or anything its been going for years in an old truck that cant get parts for.
Good luck Andrew

are you useing a ca20 bellhouseing on your stumy box if so there is a seal ring which you need to remove for the gear box gears to move ezy i had to remove on my gear box and it is working good i hope you get some thing from that

After reading all these bellhousing threads, it appears that using a CA20e bellhousing on a stumpy box doesn't require a different bearing, but using a CA18det bellhousing on a stumpy box does.

I can tell you the CA18DET bellhousing will fit on a stumpy with the change of a countershaft bearing. It may however require a sleave for the selector shaft too. This is because the selector in the CA18 box is slightly bigger 16mm.

This is probably the reason that everyone uses the CA20 bell?

Anyway pretty easy conversion, changing the bearing is not hard either.

Gday guys,
continuing on with this thread, I have swapped over the bellhousing on my r30 box with the ca20 bellhousing. Just having trouble getting enough clearance on the mainbearing to get the split ring back on.
Any tips?
cheers
Bruce
(I didn't need to change the main bearing as it was the correct size)