Hi all! Ive recently picked up a used extra transmission to go in my civic since fourth keeps grinding, and will eventually leave the chat. Im looking to rebuild the transmission im pulling out with the synchrotech carbon kit here. Id love to be able to rebuild with straight cut gears, but i cant find a 1rst or final drive gear straight cut. My question is, which gears are on which engagement shaft? and can i mix staight cut with helical as long as their all on the same shaft?

I dont know a ton about the inner workings of transmissions, so please correct anything obvious, thanks guys.

 

Think of each gear as a PAIR of matching gears, one found on the mainshaft and the other found on the counter-shaft. The tooth count of each of these gears dictate the gear ratio. To know the ratio, simply count the teeth on each gear and divide the counter-shaft gear tooth count by the mainshaft tooth count. Your issue is that 1st and 2nd gear are MACHINED on the mainshaft, so changing these two ratios requires a replacement mainshaft... which makes things pricey. Yes, you can mix helical and straight cut gears on the shafts... just NOT for the same gear pair... meaning, you can have a helical 1st and 2nd gear pair, a straight cut 3rd gear pair, a helical 4th gear pair and finally a straight cut 5th gear pair. What you cannot do, for example, is use a straight cut 3rd mainshaft gear with a helical 3rd counter-shaft gear.

The big question is WHY do you want to run straight cut gears ?

 

Thank you for the response, it was a very helpful shift of perspective! My next question is, when a company is selling 3rd 4rth and 5th straight cut gears do they mean pairs to go on main and countershaft? And the reason im trying to go with straight cut is honestly it just sounds really cool lmao. I do plan on turboing the car soon after i get the transmission issues sorted, and it definitely wouldnt hurt to be a little more stout for futer power!

 

I cannot speak for all companies that sell gears, but it is LIKELY that the 3/4/5 straight cut gear sets will include both main and counter shaft gears... for a total of six. Sometimes you can buy individual gears and you can also purchase gear pairs (third, fourth, or fifth).

 

Looks like I've got an email to send the company! thanks for your help, Ima get this thing done