• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Transmission Gears Swap

Share this page

HAN5L778

HAN5L778

Freshman Member
Offline
Way back when, early to mid 70s, I raced a Bugeye Sprite. One of the modifications I recall was to swap gears from a rib case trans into the smooth case box we were required to use. This swap allowed us to use stronger gears that had better spacing between the ratios. yeah, it was probably illegal for the class at the time, but I wasn't running to qualify for the Rinoffs. I believe that there had to be some modifications to either the inside of the case, or to the washers or spacers to make the rib case gears fit.
Has someone heard of doing this, or what needs to be done to make this swap. The reason now is that I'm building a Bugeye to sell and between the 3 smooth case tranmissions I have one has a second gear synchro that is shot, one is untested and the last was canabalized for parts for another Bugeye that I built and sold a few years ago. But I have several ribcase trans's that seem to be in good condition. Plus, I want to keep the look of the original smooth case transmission if I can.
Rick
 
I haven't done this myself, but it should work. I would recomment that the complete gear box internals need to move over. The shift forks and everything due to differences in the slide gear assemblies. There are a couple of things that need to be noted. The shifters are different. The late model shifter has a longer peg on the end and makes shifting a bit quicker in the rib-case. The shifter towers should inter-change. The mainshaft bearing plate on the rib-case has a bearing rotation prevention/location peg. So, if you keep the smooth case extension, then you will need to pull the peg or drill the extension, using the gasket or a sharpen peg as a locator. The front covers have different bolt patterns, so the old one will have to be reused.

There might be some physical interferences in the main case, like with the input gear and the lay gear, due to tooth counts, but the rest of the internals should have enough room. The center lines of the bores for the input/main and the laygear should be identical.

HTH,
Mike Miller
 
My tranny guy says he has done this in the last year or so and you move all the internals to the smooth case box. No problems and everything fits fine.
 
My dad and I did this when we rebuilt the 948 in my Bugeye. We moved all of the internals from a rib case into a smooth case, but that was over 20 years ago.

Brian
 
So we don't need ribcase trannys we just need the guts, bet that is cheeper to ship but it dosn't come in a nice alum package.
 
Back
Top