What exactly is it that causes 5-speeds to pop out of gear?

vrg3 · Post by **vrg3** » Sun Feb 08, 2004 5:25 am

A few times recently I've noticed my car (93 turbo, manual transmission) pop out of 2nd gear. Each time I had just downshifted at rather high speed, to use some engine braking going down a hill. After a few seconds it just popped into neutral.

It's possible that I just didn't push it all the way into second, and that nothing's wrong with my transmission, but it makes me wonder.

I have heard that when manual transmissions start to go they can develop a problem where they pop out of gear. What causes that to happen?

scottzg · Post by **scottzg** » Sun Feb 08, 2004 12:08 pm

the teeth of the gears start to wear, and so they will either not quite go in all the way with you shift, or they will slide out under load because of funny wear.

vrg3 · Post by **vrg3** » Sun Feb 08, 2004 4:58 pm

Hm. Thanks, that makes sense.

I'll pay more attention when I shift. Hopefully I just didn't get it all the way into gear.

NemesisEJ22t · Post by **NemesisEJ22t** » Mon Feb 09, 2004 10:01 pm

It can also be due to bad/worn synchros. When they start to go, you will notice a crunch or slight grind whenever you shift into the gear with the worn synchro even if the clutch is depressed.

vrg3 · Post by **vrg3** » Mon Feb 09, 2004 10:40 pm

I know my synchronizers (especially the one on 2nd gear) are somewhat worn... But how does a worn synchro make it pop out of gear?

NemesisEJ22t · Post by **NemesisEJ22t** » Tue Feb 10, 2004 2:44 am

I honestly have no idea exactly how bad synchros make it pop out, i remember reading a few years ago on a ToyMods mailing list about someone with your same problem which was fixed by replacing the synchros.

scottzg · Post by **scottzg** » Tue Feb 10, 2004 3:46 am

i bet the guy with the synchro problem wasn't shifting the gear all the way in.

vrg3 · Post by **vrg3** » Tue Feb 10, 2004 3:51 am

Chicken and egg, eh? That makes some sense.

I'm sure failure to fully engage a gear puts huge wear on synchros, considering you're asking them to carry the engine's torque to the output shaft.

ciper · Post by **ciper** » Tue Feb 10, 2004 4:02 am

Related? A TSB exists for a random number of Forester/Legacy/Impreza of later years
http://forums.nasioc.com/forums/showthr ... did=360145
http://forums.nasioc.com/forums/showthr ... did=130776
http://forums.nasioc.com/forums/showthr ... adid=37752

vrg3 · Post by **vrg3** » Tue Feb 10, 2004 4:20 am

Thanks for the link, ciper. I'd like to get a look at that TSB to see if it applies to my car.

I suppose I could have a loose mainshaft retaining nut, but I think it's more likely that I just wasn't paying as much attention as I should have been, and didn't get it all the way into 2nd. It's only happened three times in the year and a half since I've owned it. I do know my tranny mounts are shot.

Thanks for all the help, guys.

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What exactly is it that causes 5-speeds to pop out of gear?

What exactly is it that causes 5-speeds to pop out of gear?