3rd gear pop out

[HeWhoKillz]

I have a 91 corolla 1.6. Third gear won't stay in place. The shifter pops back into neutral. Would it be better to replace the third gear? or what are some opinions on what this is or what to do or how to fix it. Or would it be best to just get a rebuilt or junkyard transmission?

[vgames33]

That usually means that the synchro is bad for that gear. A boneyard tranny is probably the easiest way to fix it.

[HeWhoKillz]

Originally Posted by vgames33

That usually means that the synchro is bad for that gear. A boneyard tranny is probably the easiest way to fix it.

Dumb question but ill ask, whats a synchro do?

[vgames33]

http://auto.howstuffworks.com/transm....htm/printable

That has a short section on synchronizers, but should give you a good idea of how a manual transmission works.

Basically, the synchro is a ring that is allowed to slide back and forth as the gear selector is moved. One synchro controls 2 gears (forward and backward on the stick). It acts as a brake that allows the shaft and gear speeds to equalize before the shift is made, resulting in a smooth shift. If your synchro is worn out, you will have some trouble shifting into the dead gear (my 300zx has a badly work 3rd gear synchro and it has a noticeable clunk when I shift to third), or may get a grinding noise if its really bad (if I try to shift into third too quickly, it won't fully engage and I'll get the ricer gear grind and a bunch of stares from the people in other cars). The synchronizer also helps to hold the transmission in the selected gear. When it wears out, it will pop out of gear. You can bandaid this by holding the stick in position, but you will eventually need to either skip third, or just repair the problem.

You may want to check out the shift linkage before taking any action. Its possible that something is out of adjustment and won't let the shifter stay in third. Is it difficult to get into gear, or does it just pop out?

[HeWhoKillz]

Originally Posted by vgames33

http://auto.howstuffworks.com/transm....htm/printable

That has a short section on synchronizers, but should give you a good idea of how a manual transmission works.

Basically, the synchro is a ring that is allowed to slide back and forth as the gear selector is moved. One synchro controls 2 gears (forward and backward on the stick). It acts as a brake that allows the shaft and gear speeds to equalize before the shift is made, resulting in a smooth shift. If your synchro is worn out, you will have some trouble shifting into the dead gear (my 300zx has a badly work 3rd gear synchro and it has a noticeable clunk when I shift to third), or may get a grinding noise if its really bad (if I try to shift into third too quickly, it won't fully engage and I'll get the ricer gear grind and a bunch of stares from the people in other cars). The synchronizer also helps to hold the transmission in the selected gear. When it wears out, it will pop out of gear. You can bandaid this by holding the stick in position, but you will eventually need to either skip third, or just repair the problem.

You may want to check out the shift linkage before taking any action. Its possible that something is out of adjustment and won't let the shifter stay in third. Is it difficult to get into gear, or does it just pop out?

It doesn't feel anymore difficult than the others. While in second i push in the clutch moving it from 2 to 3 and then let the clutch back out and it pops straight back to neutral. Sometimes there is a small grinding. Sometimes it does and stays in gear. When it does stay in gear I haven't had it randomly pop back out. Just while its shifting.

[Moppie]

Common problem with those boxes, usually happens to 4th gear though.

It is the synchro mesh that is worn out, and it is usually cheaper and easier to just replace the box with a used one.

[Moppie]

Common problem with those boxes, usually happens to 4th gear though.

It is the synchro mesh that is worn out, and it is usually cheaper and easier to just replace the box with a used one.

[HeWhoKillz]

Originally Posted by Moppie

Common problem with those boxes, usually happens to 4th gear though.

It is the synchro mesh that is worn out, and it is usually cheaper and easier to just replace the box with a used one.

Box?

[curtis73]

Originally Posted by HeWhoKillz

Box?

Box = gearbox = transmission

[HeWhoKillz]

so it sounds to me a new or used transmission would be the best unless its possible to change a schronizer

[Moppie]

Originally Posted by HeWhoKillz

so it sounds to me a new or used transmission would be the best unless its possible to change a schronizer

With some basic knowledge and a good press it's not hard to do, but the synchro would cost as much as a used box.

Since you have to take the box out, it's just easier to put another second hand one in.