So I rebuilt my S20 at school about 2 months ago with brand new synchrotech everything..been driving the car hard and fine for about 1.5 months with no issues until the other night when it began popping out of first...what could be the issue?

 

1st gear pop out is not a very common problem. I would first check the external linkage going to the transmission to see if anything could be preventing full engagement or touching the shift linkage.

 

Yes. Check to make sure nothing is obstructing your linkage.

If that checks out, given how uncommon this problem indeed is, I would probably look to your installation of friction dampers (particularly the 1st gear one) of the countershaft - and making sure they were lined up correctly with the 1/2 synchro hub upon installation. Everything seated correctly with the countershaft when you installed the gears, bearings, and tightened the nut?

 

Check linkage and mounts. If good, split the trans open and pull the stacks out. Look at the countershaft bearing in the clutch housing. It should sit flush with the case. It has probably walked out.

 

CSB walked out shouldn't effect 1st gear popping out, only second.

Only thing I can think of is the blocker ring has parted ways.

 

One thing to check first, which is very easy to over look, is the detents. Make sure the bearing and spring aren't stuck in the bolt. I've had this happen to me after a rebuild, though I haven't figured out how that happened, it can drive you crazy with trying to think of complicated problems.

 

Naterror, sounds like you were playing with a 96-00 Civic SOHC tranny or a B tranny.

If the ball is not seated in a detent and you drive the bolt in, the end will mushroom around the ball making it HELL to get back out.

 

^^^ Yup. I've done that years ago I think twice. And I now bitch when I get transmissions other people have had their hands in and this happens. LOL I've had to tap more than one of those bolt holes because of this. I just pulled one apart where the person literally got the ***** stuck IN the spring itself. Not just the end of the bolt - causing it to mushroom.

 

problem went away on its own, don't know how but it did...out of sight and out of mind in my book....thanks to all those that chimed in.