Hey all,

Recently this past month I’ve taken the project of rebuilding my transmission.

Some Background: I’m rebuilding the s40 that came out of a 1999 honda civic dx hatchback

The engine is d16y7 (non vtec) and 1.6L obd II

This is the first time I’ve rebuilt a transmission. I took my trans out when I first bought the car I thought the clutch or something was making a bunch of noise, shortly after I replaced the clutch the noise was less but was still there. It was the input shaft bearing. So, I took out the trans and brought it inside. I started taking it apart, removed the interlock guide bolt and I separated the case half’s, pulled out the main shaft, countershaft, and fork assemblies. Then I replaced the countershaft bearing, main shaft bearing, diff bearings and oil seals. I now have the main shaft, counter shaft, fork assemblies and diff back in and I don’t know how the orientation of the “change piece” goes. In my helms it says “set the change piece” read a little bit further and it says “NOTE: Align the finger of the interlock with the groove in the shift fork shaft.”

What does the alignment look like? They show no pictures.

Also, when do I put the interlock guide bolt back in. Everywhere I read tells me first bolt out last bolt in. But does everything need to be in neutral first? Should It be in second or third gear so the trans closes then put it in? Another thing is everyone says just put it in when its an “empty” hole or has nothing on the left or right of it that would obstruct the bolt.

Lastly, how would I bench shift my trans? I have a screw driver through the nub that the linkage bolts onto but it’s so hard to pull backwards and push forwards, surely it’s gotta be something with the shift forks orientation. Also a side note is that the main shaft does spin freely so there is no binding.

Thanks all to who respond I’m just trying to figure this out

If at all possible if someone have a picture for orientation so I can compare to how my trans looks and go from there.

 

I know this is for B-series, but it's similar - 14th picture down in this post: https://honda-tech.com/forums/transm.../#post36579942
When all the gears are disengaged (neutral), the grooves at the base of each of the three shift fork shafts are all aligned, and the interlock fits inside them. Kind of hard to explain.

Get the counter shaft, main shaft, and shift fork assembly all back in the clutch housing, and disengage all gears (put it in neutral). With it in neutral, this is when I like to install the interlock bolt, before the case is on.

Use a screwdriver or a drift pin in the shift rod's "bitch pin" hole. It's more difficult than shifting the transmission in the car because you don't have the same amount of leverage, but it should shift into all gears on the bench.

 

Yes the purpose of the interlock is to make sure that only one shift fork can be out of neutral at a time, so you need to move them all to neutral first. The slots should line up. Then lift the shafts, shift forks, everything out of the case slightly so you can rotate and slide the shift dog and interlock cage into position in the slots in the shifter forks. Put in the bolt that holds the shift dog to the shifter shaft. Finally install the pin bolt that comes in from the flywheel side to limit the motion of the interlock cage.

It won't operate smoothly on the bench with the case apart, the shafts flop around too much.