Looking at buying an S15 6 speed gearbox for my Qs S14. Been offered one at a good price that works out to be pretty cheap if I factor in the resale value of my 5-speed. The reason I want it is that my S14 is NA and a daily driver; I'd love to run a 4.6 rear end to make the most of my powerband but it would be hugely impractical as a daily and a 6-speed on the 4.1 diff I have ready to fit would give best of both worlds. However, as some may know, due to bad design they have an issue where they pop out of third due to a cracked circlip that keeps third gear located on the shaft. It hasn't had the circlip mod done (Machine shaft and weld clip in place) and the prev owner (it's come off an Autech S15) reports that there is some movement/play while its in 2nd and 3rd; whether this means it's on its way out or not I dont know. Garage D can do the circlip mod for £500 incl labour but puts the conversion way out of budget for me. How likely is it that it will start popping out of gear? Is it an inevitable / common issue? Would I be stupid to fit it without doing the mod or would it likely be okay? Also does anyone know of any other pitfalls of using the S15 6speed?
Interesting! I've got an S13 with SR20DE, S15 6 Speed box + 4.4 Diff, drives great! Super quick acceleration and quick through the gears Never heard of this? Will check for play in 2nd/3rd tomorrow though haha
You normally only get the problem once you go over 300ft/lb of torque or your clutch kicking the ass out of it. But even then with an N/A motor you wouldn't be able to do the damage. So unless the box has issues already I wouldn't worry. I had my SR S15 for three years and didn't have a problem and that was running close to 300ft/lb.
Thanks for the replies, I'm gonna go ahead with it then. Can't wait to fit it woth my 4.1, I'm on a 3.7 with a 5speed atm so it should be a transformation!
