Hyudryu

Hi guys, I have a 2014 civic SI and I did the transmission a few thousand miles ago. I installed Gearx 1-4th and reused stock synchros. Now I find that I would always miss 5th gear at high rpms, other gears are perfectly fine. When I installed pistons and rods last month, I decided to crack open the tranny and see if there's anything out of the ordinary, and I found that my 4th gear was rubbing on the synchro hub and it looked as if the contact points were melting. The metal was flaking off at the edge and it's clear that something's wrong. Now i'm not transmission expert so I'm trying to figure out why it melted in the first place, but I'm going to try to buy a new mainshaft 4th gear along with a new synchro hub. Right now, my transmission is as is, (I pressed everything back the way it was) and I'm still missing 5th. 5th would just completely lock me out at high rpms and I have to hold it there till the rpms drop low enough before it would engage.

Things I remember from my initial rebuild:

-I pressed everything in till the part reached the end
-I reused the spring washer and shim at the end of the mainshaft
-I got all new shaft bearings for the mainshaft and countershaft
-Oil was filled slightly higher, I poured 2.1 quarts when our car needs 2
-(This is what I think was the problem, but I just wanted to be sure so I won't melt another gear after I purchase a new one) A few days after I first rebuilt the transmission, the car would get stuck in reverse and the tranny would lock up; Pulled it apart and found that the bolt on the countershaft came loose so I used red loctite on it and it was fine ever since. Not sure if this is what caused the parts to get damaged, if it is I'll just replace those 2 parts and my transmission would be good again but I want to see if there's anything else that can cause those parts to rub and create so much heat like that.


4th mainshaft gear
3/4 synchro hub on the mainshaft



Any help is appreciated, thanks

-Mark

Aquafina

iTrader: (3)

You need to shim the mainshaft and countershaft. K series gears are not "bolt-in". Countershaft shim clearance must always be checked and mainshaft shim clearance must always be set.

Hyudryu

Thanks for the help, how exactly do I measure the clearances? Iirc, there's a shim and spring washer for the mainshaft and there's a shim on the countershaft on the top between 6th gear and the bearing. To my knowledge, shims are used to reduce play but how do I check for play?

Aquafina

iTrader: (3)

The mainshaft shim is in the transmission case, it retains the oil guide plate. You need some OEM specialty tools to check the mainshaft shim clearance along with a dial gauge. For the countershaft you just need a set of feeler gauges. Both procedures are outlined in the Helms manual.