Credit for this write-up goes to Shaun Quickel "HondaBull" on Honda-Tech.

BACKGROUND:
The transmission I will go over is my spare 1995 GSR transmission I’ve had lying around for two years now. Luckily, I knew what was wrong with it prior to opening it up this time, as I had it in my car for about two months at one point. It was excellent everywhere, except it ground 3rd at anything above 5500 rpm. So this is what I will set out to fix for this tutorial. I assumed that it’ll be the synchronizer, and have a used one available that I received for doing some transmission work for a friend of mine. So we’ll open it up, inspect various parts, replace the synchronizer, and seal the transmission back up.

TOOL LIST:
The bare minimum you need to simply open the casing up and reseal it:
2x4 blocks of wood (2)
1/2” ratchet (1)
3/8” ratchet (1)
10mm 3/8” deep-well socket (1)
12mm 3/8” socket (1)
14mm 3/8” socket (1)
Needle nose pliers (1)
Razor blade (1)
Tube of Honda Bond (1)
8” - 17”pry bar (2)

Helpful:
3/8” extensions
1/2” extensions
Dead-blow mallet (1)
Torque wrench (1)
Magnet (1)

Required to replace synchronizers (mainshaft):
3-arm bearing puller

Required to replace synchronizers (countershaft):
3-arm bearing puller
32mm 1/2” socket
1/2” air gun with compressor (or a big breaker bar and some luck) (1)
Bench mounted vice (1)

GENERAL RULE: I have tried to keep all explanations appearing ABOVE the photos posted. If you see a photo and want to see specifically what is being written regarding that photo, scroll up to the first paragraph above.

Here you can see the transmission mounted up on two simple blocks of wood. This allows the transmission to be elevated so that the mainshaft does not bottom out against the ground. This is vital for trying to seal up the case at the end of the process.



RED – C-clip bolt with 1/2” socket bolt (1)
PURPLE – 14mm reverse idler gear bolt (1)
GREEN – 12mm bracket bolts (2)
TEAL – 12mm shifter bolts (2)
ORANGE – 12mm transmission case bolts (17) – 3 bolts are hidden from view due to the camera angle

Also pictured are the speed sensor, reverse sensor, oil drain plug, and oil fill plug. None of these need removed to proceed.

So, we can now begin digging into this thing. Remove both 12mm bolts (TEAL ARROWS in the previous photo) and washers which retain the shift fork springs and balls; take care not to lose the balls – a magnet will help extract them out of the bolt holes securely. You can also simply cusp your hand beneath each bolt hole and tip the transmission over so that the balls roll out.

Remove the 14mm reverse idler shaft bolt (PURPLE ARROW) with its washer. Then, simply by using the ½” ratchet, remove the c-clip retaining bolt (RED ARROW).

Now you can remove the c-clip from the groove in the countershaft bearing. There are several ways this can be achieved: 1) snap ring pliers; 2) needle nose pliers; 3) two flathead screwdrivers. The snap ring pliers are the easiest method, as you just have to squeeze the handle together. I normally just use the needle nose pliers, but you will typically have to use both hands to spread the handle apart. You will also need to use both hands to use the two screwdrivers. Regardless of the method, get the tips of the tools in between the two ends of the c-clip and pry it apart. The countershaft will drop due to its weight, and you will be notified of this drop by a distinct “clunk”.

Here is a BEFORE and AFTER of the c-clip.

Remove the two 12mm bolts (GREEN ARROWS) to the bracket at the top side of the transmission by the vent. These will uncover another 12mm bolt responsible for holding the two cases together.

Finish by then removing the remaining 17 12mm bolts (ORANGE ARROWS) which keep the two cases together. Once they are out, you are ready to pry the upper casing from the bell housing. Get a prying mechanism (pry bar, tire iron, etc.) and place one end into the available slot on the front side of the transmission – this unfortunately is the only decent prying point on the B-series and K-series transmission; D-series on the other hand have two pry points.

Once you pry that up, you’ll notice that the other end of the transmission had a difficult time coming apart. There are two locating pins between the two housings which could get damaged by further prying like that. So get another pry bar or even a flathead screwdriver, and go to town on the other end of the transmission. It will normally pop right open with ease.

With the two cases now fully separated, simply lift the casing straight up, taking care to avoid heavy contact with the gear clusters inside. If you are having difficulty with this, it could be a few things. The bearing on the top of the mainshaft (commonly referred to as the input shaft bearing, or ISB) is tight in the casing and on the mainshaft, causing some trouble. The peskier issue is when a sealed differential bearing becomes tight in the passenger side transmission case. When this happens, as you pull the case up, the differential pulls with it, ultimately hitting the countershaft and preventing you from pulling the casing up any further. Either way, light taps to the casing with a dead blow hammer will normally free up these bearings. The roller bearings of the older GSR and ITR transmissions (those found in this particular GSR transmission) will never have this problem in the teardown and rebuild process.

These are the two casing halves separated finally. In the second photo, you can see that the mainshaft bearing has pulled up with the casing. If this happens, tap the casing against the surface you are working on to make the bearing drop out (it is nice to have a towel or something down to catch the bearing with to give it a soft landing).