Won't go into first when hot and in traffic

[kevman_101]

There is no lock out for 1st, but I'm pretty sure there is no syncro for 1st either. So even with the clutch, it's not the easiest thing to do to get it in 1st when going much faster then 5 mph.

[SeanBlader]

Originally Posted by kevman_101

There is no lock out for 1st, but I'm pretty sure there is no syncro for 1st either. So even with the clutch, it's not the easiest thing to do to get it in 1st when going much faster then 5 mph.

There's definitely a synchronizer for first gear, otherwise from a dead stop you'd have a hard time getting it into first and you'd need to double clutch it every time, once to spin up the intermediate shaft and once to get it into gear.

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

The problem the OP had was the extreme difference between engine speed and wheel speed when trying to go from second into first gear. The easy solution is to rev match between gears getting the engine to a more comparable speed to the intermediate shaft, or you can also double clutch, thereby bringing down the speed of the intermediate shaft closer to the speed of the motor. The latter would mean a heavier jerk as the motor had to spin up to wheel speed very quickly when you release the clutch a second time, so with decent transmissions in performance driving situations, it's better to rev match when down shifting. There is a certain "touch" required there, so that you know how much to rev match, as too much gas or too little will also upset the suspension, potentially sending you into a spin. In a nutshell, all that is why race car drivers are far more under appreciated than they really deserve by your average driver.

[OrbitalEllipses]

Originally Posted by kevman_101

There is no lock out for 1st, but I'm pretty sure there is no syncro for 1st either. So even with the clutch, it's not the easiest thing to do to get it in 1st when going much faster then 5 mph.

Triple cone carbon synchronizer on first and second, possibly on third though I concede third might be double cone. I don't have the TL70 spec sheet in front of my right now unfortunately.

[DylanFRS]

Originally Posted by SeanBlader

The problem the OP had was the extreme difference between engine speed and wheel speed when trying to go from second into first gear. The easy solution is to rev match between gears getting the engine to a more comparable speed to the intermediate shaft, or you can also double clutch, thereby bringing down the speed of the intermediate shaft closer to the speed of the motor. The latter would mean a heavier jerk as the motor had to spin up to wheel speed very quickly when you release the clutch a second time, so with decent transmissions in performance driving situations, it's better to rev match when down shifting.

It's odd that you speak of double-clutching and rev matching like they mutually exclusive. I never just rev match without double clutching. If you don't engage the clutch while rev matching then the input and output shafts won't match speeds.

Correct me if I am wrong, but solely doing rev matching will match the engine speed to the correct ratio of the wheel speed for the next gear. So you get rid of the jerkiness (clutch forcing engine to correct speed for next gear). But, you are still relying on the synchros to match the input and output shaft speeds.

[Chee-Hu]

I've had this happen to all my cars. Completely stopped at a red light, disangage (press) clutch, try to shift into first, no luck. Solution is to depress and press clutch again and it goes in. I didn't think it was an issue and have never forced it into gear.

[OrbitalEllipses]

Originally Posted by Chee-Hu

I've had this happen to all my cars. Completely stopped at a red light, disangage (press) clutch, try to shift into first, no luck. Solution is to depress and press clutch again and it goes in. I didn't think it was an issue and have never forced it into gear.

How soon after stopping? Could be the input shaft is still spinning (that's the clunk you hear when you put it 1st at a stop).

[Chee-Hu]

Originally Posted by OrbitalEllipses

How soon after stopping? Could be the input shaft is still spinning (that's the clunk you hear when you put it 1st at a stop).

Most times I've been sitting at the light for at least a minute or two. I don't normally try to shift into first as soon as I stop. The BRZ has only done it a couple of times though unlike my previous Hondas which used to happen at least once a day.

[SeanBlader]

Originally Posted by DylanFRS

Correct me if I am wrong, but solely doing rev matching will match the engine speed to the correct ratio of the wheel speed for the next gear. So you get rid of the jerkiness (clutch forcing engine to correct speed for next gear). But, you are still relying on the synchros to match the input and output shaft speeds.

They aren't mutually exclusive, but one is a lot easier and quicker. Rev matching is done when you're trying to get into gear in the middle of a turn that you're already at the limit of adhesion. Double clutching is done when your transmission is a POS. ;-) My other car is 29 years old, and I don't need to double clutch, so I'd wager that if you do need to double clutch, you probably have synchronizers going out and should get that looked at.

[Kevstra]

Originally Posted by DylanFRS

It's odd that you speak of double-clutching and rev matching like they mutually exclusive. I never just rev match without double clutching. If you don't engage the clutch while rev matching then the input and output shafts won't match speeds.

Correct me if I am wrong, but solely doing rev matching will match the engine speed to the correct ratio of the wheel speed for the next gear. So you get rid of the jerkiness (clutch forcing engine to correct speed for next gear). But, you are still relying on the synchros to match the input and output shaft speeds.

Correct. When you blip the throttle (accurately) the engine RPM (approximately) equals the output shaft RPM (x gear ratio of next lowest gear), but since you disengaged the input shaft from the engine with the clutch before you blipped, the input shaft is still spinning at the old engine RPM. When you put the gear shift into the sequentially lower gear following the blip, the syncros must spin up the input shaft to the new engine RPM.

While that sounds bad cause poor syncros are being worn (gasp), that's exactly what they were designed to do! Everyone's got a soft spot for syncros, but they have been engineered to be used in exactly this way for the life of the vehicle.

Kudos to those that double clutch, but you aren't wrecking your transmission by neglecting to do it. It's like saying you're wrecking your brakes by using those. Under normal use, the syncos in your transmission should last 150,000-200,000 kms. At which point they can be easily replaced with either patience or money.


More regarding the OP's message: If you can't get it into first gear while standing dead still, I'd have that looked at. Try replacing your transmission fluid first though. I know I had a bit of trouble when the transmission was cold. If you're rolling, you just need to do a hella good job of rev matching like others have said.

And I'm glad others have corrected the hilarity of first gear not having a syncro.

[DylanFRS]

Originally Posted by SeanBlader

They aren't mutually exclusive, but one is a lot easier and quicker. Rev matching is done when you're trying to get into gear in the middle of a turn that you're already at the limit of adhesion. Double clutching is done when your transmission is a POS. ;-) My other car is 29 years old, and I don't need to double clutch, so I'd wager that if you do need to double clutch, you probably have synchronizers going out and should get that looked at.

Maybe our definitions are different. To me, double clutching is disengaging the clutch twice when downshifting and rev matching is something you do to match engine speed with what it should be in the lower gear. You would never double-clutch and not rev match, but I definitely see a lot of people that rev-match and don't double clutch.

Rev-match no double-clutch:
1. Disengage clutch
2. Shift to lower gear
3. Raise RPMs (blip) to match lower gear
4. Engage clutch

Rev-match w/ double-clutch
1. Disengage clutch
2. Shift to neutral
3. Engage clutch
4. Raise RPMs (blip) to match lower gear
5. Disengage clutch
6. Shift to lower gear
7. Engage clutch

Rev-matching only will help save the life of your clutch and provide a smoother downshift.

Rev-matching while double-clutching will do everything rev-matching will while also taking the load off your synchros.

Just double-clutching with no rev-matching does nothing.

And I do know that I don't need to double-clutch. And I don't need to rev match. And I don't need to drive a manual transmission. I do all of it for my enjoyment. Executing a few near perfect rev-match downshifts while double clutching and braking (heel-toe?) is a fun feeling.

[mrha]

My problem happens when I'm at a dead stop and not rolling. It is good to know I'm not the only one that noticed this happening in their cars.

[Pneub]

I have the same issue. Currently in the process of replacing the clutch and flywheel. Will post again when I have results. I sent you a personal message mrha.

[SirBrass]

Originally Posted by kevman_101

There is no lock out for 1st, but I'm pretty sure there is no syncro for 1st either. So even with the clutch, it's not the easiest thing to do to get it in 1st when going much faster then 5 mph.

All 7 gears in this car (1-6 and reverse) are synchro'd. That's why there's a reverse lockout. In a 5 spd, I'm pretty sure reverse is not synchro'd. I could be wrong on that, though.

[onabulletride]

Originally Posted by SirBrass

All 7 gears in this car (1-6 and reverse) are synchro'd. That's why there's a reverse lockout. In a 5 spd, I'm pretty sure reverse is not synchro'd. I could be wrong on that, though.

I think you're right, reverse is usually a straight cut gear.