Hi guys,

Need a bit of help here, I have a Y21 transmission, I've just replaced the final drive. I have everything finished and ready to stick the case back on but thought I'd try the gears and realized its locking up in 4th

I've taken the forks out and stripped the mainshaft and put it back together again to check for any problems which there weren't (I never touched the main shaft anyway)

I have another gearbox which has the case off and have noted which selector moves for 4th so I can manually select it and it still locks up. Any one have any ideas? Its grinding my gears (excuse the pun)

All the other gears seem to be okay, check the video too!


http://www.youtube.com/watch?v=qLzCrG36UF0[/youtube]

 

That's 3rd. Not 4th.

No one mixed any gears up from another transmission? I see it still spins without it engaged, so the gears are probably still matched. Is the bottom of mainshaft 3rd okay? Not damaged or worn down?

And it still spins when you engage 1st or 2nd or 5th, etc.?

 

Oops sorry wasn't sure if it was 3rd or 4th! Nope the gears are all from the same transmission, I was driving the car with this box only 2 weeks ago. Mainshaft is fine, hasn't been messed around with. When I take both the shafts out, one of the gears spin on the countershaft and the gears on the mainshaft move freely

Is there anything I should be looking out for?!

 

Okay found the problem! Thanks to having a spare box phew! Took the countershaft out the spare box and after some playing around realised the very bottom gear on the problematic countershaft wasn't turning at all, so I took it all apart (Damn I had got that 32mm nut on the top tight with loctite! Needed to use the impact) put it back together and its working as it should now

Not sure if it was the gear that wasn't sitting right or what?

Looks like its gonna be a busy night tonight whacking the gearbox together, I'm way behind schedule

 

Good to hear you figured it out!

From the video, I wished you had gone into another gear. Not just 3rd. Because if 1st was locked up, any of the other gears would have locked up as well (can't have two ratios spinning two shafts at different speeds at the same time). I saw none of the sleeves were engaged, but that doesn't mean a needle bearing or something isn't preventing the movement of non-splined gear.

 

Thanks Honda Bull, I put it together again last night and it was fine for a while but it seems to be locking up again, my guess is its the same gear on the bottom of the countershaft? Any ideas why its doing this? I'm thinking maybe the something to do with some countershafts using a collar and some not?

My old one didn't have a collar and the needle bearing the gear sits on sits perfect on the new one so I don't think the countershaft is wrong?

Cheers

 

What type of FD are you installing?

There are two different style countershafts for the B series. It sounds like you may have installed a 98+ JDM spec FD that requires a collar, larger needle bearings, and different first gear. If you put your USDM 1st gear on this type of countershaft it will bind up.

 

This. Did you put an OEM 4.785 or ATS 4.9 final drive in it without all of the correct 1st gear components?

 

Its a custom final gear made here in the UK. The engine is in a classic mini and the stock honda final drive is a handful with 10" wheels So a 3.4 has been fitted.

Is the countershaft likely to be at blame? I'm going to strip the gears off it tonight and compare it to the old one, what should I be looking for which is causing the locking up of the 1st gear?

Thanks

 

It is most likely the hub to gear clearance for the C/S first gear. The shoulder on the shaft works as the inner race for the two needle bearings and spaces the gear along with the washer. Your custom shaft will need to be machined to the same specs as the OEM shaft.

 

Hey

I appreciate the help on this, I spoke to the guy who supplied the fds and he's assured me everything should be okay. He's built up some boxes with fds from the same batch and says that they are running in the car fine. I've taken pictures of the counter shaft comparing it to my original one

First of all, one difference between the new and old is the slot for the tab at the top? Not sure what it was about but read up that hondas came with both?
Original oem one had the longer slot where as replacement had just a short slot going down meaning I had to cut out the tab of the washer which goes under the nut




What I notice is the gear when it does turn, doesn't turn very smoothly like the 3rd gear does? Here's some pics of the clearances with it all assembled





Pictures of where the bearing for the 1st gear sits, this box has the 2 split type. Oem on right replacement on left







I've noticed the oem one has a slight groove? The replacement doesn't have this



Oem right and replacement left





No scoring on the inside of the gear when it's locking up



The split bearing



Hopefully these pictures should help? Really hoping I can solve this soon as i really want to be driving it again



Very messy engine bay!




Thanks

 

The gear is probably binding on the 1-2 hub. Try assembling the shaft without the sleeve and synchros or dampers. You should be able to see the gear clearance for 1st and 2nd. Both gears should spin freely and have about 5-10TH up and down movement. There is a selective sized washer (Shim) that goes under the first gear. You can adjust the gear clearance by changing the thickness of this washer. First I would measure the shaft to see if it matches your OEM shaft. Don't worry about the top washer under the nut. Honda uses two different designs: a long groove (with a tab on the washer) and a short groove (without a tab on the washer).

 

The supplier thinks it is a endfloat problem as the 1st gear is locking up once the nut is torqued up. How do I go about finding out which thickness I need?