***STICKY*** - Timing Belt & Transmission Rebuild Thread (2005 NSX 6MT)

[99 rs]

Now for some crossing of the fingers and trying to replicate the OEM setup as best I could for measuring shaft runout. At first I had the dial gauge set up on the cardboard and paper towels but I was getting strange movements. Once I put the setup on the flat table the readings settled down.

I used the press blocks to hold the shaft.

Also notice the lubrication ports so don’t have your needle skip over that.

The service manual only calls out to measure the runout at 1 spot. I measured on all the flat surfaces where the bearings sit as well as close to the snout.

 

[99 rs]

Here is the video for the service manual location. The runout is nil. At this point the dealership would call this shaft good and move on I reckon.
https://youtu.be/WRkXftPYTY4

I also checked on the other side of the lubrication hole on the same plane.
https://youtu.be/zn1kW-394kw

Here is runout closest to the “top” where the bearing took the impact.
https://youtu.be/7-tCLNMMDUg

I checked the clutch side bearing location and I see a runout of ~ 0.0005 (half the standard limit of 0.001). Not great; not terrible.
https://youtu.be/3MX6hA2Kac8

I then checked the runout closest to the snout impact point. I’m seeing pretty much bang on the maximum standard 0.001 inches. It’s well within the service limit of 0.002 inches. Thinking about this realistically, if I buy a new shaft, there is a good chance the new one can come and have a runout of 0.001 and that’s perfectly acceptable to Honda (ie part is not defective). I’m leaning towards not replacing it. The consensus I’m getting over here is I can take the shaft and go chip ice off my driveway with it and the runout won’t change.

https://youtu.be/2xRwrSRByFo

 

[99 rs]

Countershaft Disassembly

Just like the mainshaft start with the clearance measurements. Here is the 2nd/3rd clearance.

..and the reverse to 1st clearance

I’ll do all the following measurements properly once I strip the gears off. All shaft OD’s came back slightly larger than standard so far.

The countershaft nut on my car is 41 mm.

 

[99 rs]

Some pictures of the 1st/2nd synchro sleeve. The fat bit of the sleeve points towards 1st gear on the left side of the picture

Can anyone educate me as to why the gears are missing some synchro teeth? They’re spaced 120 degrees apart.

The casting of 6th gear also isn’t the best but it’s in a non load bearing part thankfully. Look at the 5-6 o’clock position.

I chiseled away some wood blocks so I can hold the countershaft like the service manual says but as I was chipping away I noticed my compressor had ~50 psig residual pressure left in it. I put the impact gun on the nut (after removing the stake) and the nut came off quite readily.

Lastly for today, is the needle bearing just below the ball bearing supposed to be loose like this?
https://youtu.be/ZWfCRgvvWlU

 

[99 rs]

Got the countershaft all taken apart. Definitely needed a press for this one. Even reverse gear was kind of stuck on for me.

Readings from last time around.

Start with getting the needle and ball bearings off along with 6th gear. When I went to attempt to press these out I found the press span wouldn’t clear 1st and reverse gear. So I did what any sensible man would do and unbolted the safety ties between the load beams and operated the machine that way.

I doubt the 20 tonne capacity is there anymore but honestly we’re no where near that for the force this requires.

 

[99 rs]

First press of the day. The press blocks were perfect for 6th gear.

Next is 4th and 5th gears:

 

[99 rs]

Then for 2nd and 3rd I attempted the same maneuver as when I dropped the mainshaft as this time I had no choice. I had to use the thin flat metal as the thick press blocks fouled on the shift sleeve. I had my wife do the pumping while I held the shaft just in case but thankfully no issues this time around.

2nd and 3rd free:

 

[99 rs]

After that, the shift hub, synchros, and 1st gear just come right off.

Reverse gear:

 

[99 rs]

Behold my bare thick counter shaft:

 

[99 rs]

Now the individual components. First up is the reverse threaded lock nut and the conical washer they say not to re-use (which I won’t).

Ball bearing that the snap ring sits in.

I think I found the source of my problem. When I spin the countershaft “snap ring” ball bearing I get a washboard sound. The other ball bearings didn’t do this. I’m replacing all bearings anyways but I’ll cut this one apart to see the inside of it.

https://youtu.be/5s8fdlBarqo

 

[99 rs]

Next up is the needle bearing. This was the one I asked about up top there. I think that’s normal the more I look at it as this one might have to handle expansion and contraction.

A bunch of wear on this one:

6th gear looks all good.

 

[99 rs]

5th gear looks good.

4th also looks good.

 

[99 rs]

Ditto with 3rd.

 

[99 rs]

Now onto 2nd. I grinded this one hard several times (user error) so I’m replacing it no matter what. Although the gear itself looks pretty good if I’m honest.

Next up is the spacer collar:

 

[99 rs]

Then the 2nd gear synchro. Dual cone goodness.

Then the 1st/2nd synchro sleeve, synchro hub, and 1st gear synchro:

 

[99 rs]

The sleeve really is quite rounded. The pointy bits towards the outside don’t play a role since they don’t actually reach the gear. These are almost completely rounded in some spots.

This synchro hub is symmetric.

 

[99 rs]

1st gear looks good.

Has some strange arrow like markings:

 

[99 rs]

The reverse gear and the needle bearing for 1st gear is shown below:

My shim thickness is 1.43-1.44 mm so the smallest shim available. But my clearance was bang on in the middle so no issues.

I now have all 7 gear synchros measured up. All were within spec so none of the cones have worn out. I suspect the teeth get worn out long before the cones ever do.

 

[99 rs]

I measured the thicknesses and same as the mainshaft all came in slightly larger than standard. Again it’s probably why I needed the press.

Now the countershaft runout. The service manual says to measure in the middle but on my shaft that’s right where a rough patch is. I seriously doubt they mean to measure that rough patch. I still did and surprisingly it was still within the 0.002 inch runout limit but I used my judgment for the other points on the shaft.

Service manual spot:

Look at all the bumps and imperfections in that spot:

First the runout in the service manual spot:
https://youtu.be/3P9k4mJEb6k

Then the runout on the unfinished part of that same spot. Note I think I bumped it half way through the video as the needle jumps below 0 starting from that point. Either way, right around 0.002 inches.

https://youtu.be/0JgDXbxlfaI

I also checked the other finished spot on the shaft:
https://youtu.be/HOe0S5w-Jn8

 

[99 rs]

With that everything on the countershaft is done.

 

[99 rs]

Now I moved onto the clutch side countershaft needle bearing. Found yet more pieces of magnet.

I don’t understand what those oil ports on the top of the bearing are there for. They don’t get fed from the oil pump guide plate. That plate directs the fluid into the countershaft. Unless it’s just a gravity feed type of arrangement into the bearing. Might even be fluid relief since the bearing spins quite fast I imagine.

I used the same method as other people for removing the bearing. Break apart the plastic cage, remove the needles, then use the inner race as the pry point. I used a slide hammer and I admit it was way more force than I thought it would need to come out.

 

[99 rs]

Point of no return:

The carnage:

Plenty of bite:

 

[99 rs]

The slide hammer:

 

[99 rs]

Now I went on to removing any remain seals and outer races.

First the shift lever (on the clutch housing).

It has some odd staked washer on the inside of it.

The input shaft seal can come out from the front or the back. Pick which ever side you prefer.

Then the select lever (on the transmission housing).

It has that same staked washer.

Also found out there was still a piece of the reverse gear solenoid lockout remaining in my transmission case. It moved just a touch when I pushed on it from the inside so thankfully I caught it now and not when I’ll be blowing it out with compressed air upon reassembly.

 

[99 rs]

Next up is the differential bearing outer race on the clutch side. This one came out way way easier than I would have expected. Border line finger tight and only needed the most lightest of taps.

2.555 inches was closest to the required size.

The oil guide appears to have some abnormal wear. Look in the inside of the guide; that light colour area is not the light reflecting but actual wear. Service manual calls to replace it but still would be nice to know why it’s like that.