Your G is unique to itself. Have the dealer look into this. Good luck!

 

There is no "gate", it's when the soft ring revs match the sync speed... The gate is in your mind, it's a virtual thing. Back many years ago, manual shifters had gates that guided the main shift rod inside the car, coming from a mechanism that was usually bolted to the tail housing of the transmission and attached to rods which connected to another mechanism that turned a little piece that stuck out of the transmission housing. The gate was needed to keep the shifter from traveling too far also, it helped guide you into the desired gear... This has all gone away, like I said there is NO GATE anymore, it just feels that way, it is just a characteristic of the 6MT.

Borg Warner T10 pictured in link (most popular type, gate bolted to housing)
http://laodice.no-ip.org/BWT10.jpg

Old type gate assembly link (this type was inside the car and connected with rods through floor)
http://laodice.no-ip.org/shiftgate.jpg

Our Transmission type in this link, ((not a nissan but very close in design, no gate, shifter goes directly to shift rods & forks inside) could not find a good picture of our 6MT)
http://laodice.no-ip.org/6spd_generic_rwd.jpg

Explain it any way you want, but there is no gate, no little thing that drops down in front, it may feel like it and you could probably get someone that has no clue about manual transmission designs to agree, but it is all fiction.

Since the thread started I've tried several times and have no problem shifting down into 1st. from as high as 20MPH if I rev match, no rev matching and its more like 2-3MPH and you can feel the sync trying to fall into gear, this is what you are describing as the gate or thing that is dropping, no thats not what your feeling, it's definately the sync.

 

Ok so I noticed when I went out friday night my 240sx has a first gear lock out thing too. I push the clutch in all the way right before I stop at a light or sign and try to move the shifter into first BEFORE I stop and it won't go on. After I stop it goes in. It happened twice and yes the clutch was ALL THE WAY IN but I was slowing to a stop. I couldn't figure it out. Oh well just gotta wait till I stop completely to shift into first.

 

Wow, I remember those videos from a few years ago, but the links seem to be down. Am I missing something or is there somewhere else to get them?

 

That's exactly what I'm talking about. I noticed same thing on my 93 Probe GT, my 2001 Maxima, and now the G. No matter what we call it, I just wanted to say that it's there, to prevent those inexperienced to shift into 1st easily, when not supposed to. Thank you.

 

Digging this up from the grave, are we?

 

I know exactly what he is talking about. You need to rev-match. It still feel's a little notchy, but it helps a lot.

 

i know what u mean.. where u cant exactly put the gear in first even though u are going like 5 mph. Yah but what the heck i shove it in anyways. =)

But most of the time i just take my time and then turn.

 

Okay my turn to add.

Yes the G does block you from going into first gear, unless the car slows down enough. If you rev the engine to sync 1st gear, you can get into first a lot more quickly, but it still feels kind of weird. If you follow Andy's approach you should be able to get into first gear, it just requires you to rev the engine a lot depending on what speed you are at. I would not recommend it tho because 2nd gear is usually sufficient, but if you want to do a donut on an intersection well now you know how.

 

Just mess with it and fool with it till it feel right? Its not too hard. Isnt it supposed to be harder to throw it in first? I kinda push hard for it to go itno first when im downshifting.

 

hmm. someones needs to brush up on their MT driving. parallel parking, however, on the inclines of san francisco actually needs to be worked on. otherwise, driving on most roads should be like driving an AT.... like second nature and effortless.

 

What you're dealing with is no synchro on 1st gear. So, the layshaft speed must match the output shaft speed for the dog teeth to grab the collar on the gear and thereby engage 1st gear.

First a little tranny anatomy... You have an input shaft coming from the engine into the tranny. It is ALWAYS connected to a layshaft, so they spin together. The layshaft has gears on it that ALWAYS spin with it. These gears are constantly meshed with gears on the output shaft that leaves the transmission headed ultimately to the rear wheels. The gears on the output shaft can spin freely unless they are engaged. When you engage a gear, you are biting into the collar on the gear on the output shaft, thereby forcing the output shaft to now spin at the speed that gear was spinning at:

http://auto.howstuffworks.com/transmission.htm

So, when you are stopped, idling with the clutch released and the stick in Neutral... the input shaft spins with your engine ~600rpm. The layshaft also spins at that speed. The gears on it spin at that speed. Each gear on the output shaft is spinning at a ratio of that speed (most slower, one or two faster). The output shaft is not spinning at all, since the car is stopped.

Now, the subject at hand.. shifting into agear (1st) with no synchro while moving:

There are several ways to accomplish that, but the most reliable way is to double-clutch: select neutral, release the clutch pedal. This connects the engine to the layshaft (via input shaft), but disconnects the layshaft from the output shaft since the transmission is in neutral so none of the gears is forcing them to turn together but rather all spinning freely on the output shaft.

Now, rev your engine up, to spin up the layshaft (and all the gears). You should rev it maybe a little higher than 1st gear would be, to give yourself sometime to do the rest of it.

Next press the clutch pedal down. This will disengage the engine from the layshaft... the layshaft will immediately begin to slow down from friction, but it has a good amount of mass so it will have some momentum and take some time to slow down. At this point you want to press the shifter towards 1st gear. When the layshaft rotational speed matches the required speed for the gearing ratio so that the gear on the output shaft can spin at the proper speed and also spin with the layshaft, 1st will go in. Now you need to let the clutch out. You probably want to blip or just steady apply throttle at this point so you don't have an idle speed engine trying to match a high speed spinning layshaft.

What you feel when you come to a stop, sometimes even after you stop for a second or two, is the layshaft still slowing down. Anyone can try this... approach a stop sign in 1st gear at some speed (20mph), wait until pretty late to stop and stop a little quicker than normal. BEFORE you stop, put the clutch down and take the car out of gear as if you are getting ready to select first... As soon as you do that, the layshaft is not connected to the engine NOR the output, so it spins down slowly by itself... it will not always be stopped by the time the car is stopped, and when you think it is ok to push 1st in, you might feel some knocking thru the stick, as the dogteeth can't manage to mate up with the collar on the gear, since the layshaft is spinning and the output shaft is not.

Hope that makes sense

 

Yeah I usually just do 2nd... but sometimes I'm rolling at 15mph and need to accelerate quickly.. .there's a huge difference between 1st and 2nd acceleration at those sorts of speeds..

It IS rare though.... at a race track however, I could totally see an advantage to heel toe-ing into first at times instead of bogging in 2nd.