Manual Transmission Locking

[conozo]

As some of you know ive hit a road block with my build.

I've converted the car from carb to fi and auto to manual. I had my brother in law rebuild the transmission, all it needed was a 5th gear synchro and new seals, he measured everything and it was all in spec. I have been able to drive it around the blocks a couple of times. BUT I have the following problem.

When in neutral and not moving with the clutch pressed down, i havent had it die but ive been afraid to push it as hard
a couple times around the block, i was in 2nd going 15-20mph, the tranny seized, car came to an abrupt stop (actually had a bruise from the seatbelt it was that quick). Started the car again and was able to continue the rest of the way.
Once it seized while reving it in the driveway, everytime i started it back up, it would stall/seize when releasing the clutch, the only fix was to get out and push the car an inch or two then i could release the clutch and drive it.



After studying how the tranny works, here are my assumptions

It appears that its going into two gears at the same time somehow especially when the revs get higher
The clutch adjustment appears to be good, engaging and releasing


My questions

What are your thoughts on how this is happening?
How can a manual transmission go into two gears at the same time?
Is a synchro backwards or a shift fork not engaging or disengaging?
I dont know how the shift forks work in this car, is it possible that one is not connected or loose?
Am i a wuss for not wanting to drive it to avoid damage to it when it seizes just for diagnosing it and all the gears. I'm assuming its a ton of force on the transmission case stopping a car dead in its tracks especially with my grippy tires.

[Oldblueaccord]

As some of you know ive hit a road block with my build.

I've converted the car from carb to fi and auto to manual. I had my brother in law rebuild the transmission, all it needed was a 5th gear synchro and new seals, he measured everything and it was all in spec. I have been able to drive it around the blocks a couple of times. BUT I have the following problem.

When in nuetral and not moving, if i rev it up to 4k or so, sometimes it will just die instantly.
When in neutral and not moving with the clutch pressed down, i havent had it die but ive been afraid to push it as hard
a couple times around the block, i was in 2nd going 15-20mph, the tranny seized, car came to an abrupt stop (actually had a bruise from the seatbelt it was that quick). Started the car again and was able to continue the rest of the way.
Once it seized while reving it in the driveway, everytime i started it back up, it would stall when releasing the clutch, the only fix was to get out and push the car an inch or two then i could release the clutch and drive it.



After studying how the tranny works, here are my assumptions

It appears that its going into two gears at the same time somehow especially when the revs get higher
The clutch adjustment appears to be good, engaging and releasing


My questions

What are your thoughts on how this is happening?
How can a manual transmission go into two gears at the same time?
Is a synchro backwards or a shift fork not engaging or disengaging?
I dont know how the shift forks work in this car, is it possible that one is not connected or loose?
Am i a wuss for not wanting to drive it to avoid damage to it when it seizes just for diagnosing it and all the gears. I'm assuming its a ton of force on the transmission case stopping a car dead in its tracks especially with my grippy tires.



"When in nuetral and not moving, if i rev it up to 4k or so, sometimes it will just die instantly."

Doesnt sound like the trans when I first read this.

I think you are correct not to really drive it it sounds like it could be dangerous.

I would try and verify what is :"locked up" as you say. Carefully get it to do it and then immediately jack up the front end and see if the wheels are indeed locked.

My only experience with this is when my AC compressor went bad it would lock the motor. No belt squealing no other sounds.

[conozo]

"When in nuetral and not moving, if i rev it up to 4k or so, sometimes it will just die instantly."

Doesnt sound like the trans when I first read this.

I think you are correct not to really drive it it sounds like it could be dangerous.

I would try and verify what is :"locked up" as you say. Carefully get it to do it and then immediately jack up the front end and see if the wheels are indeed locked.

My only experience with this is when my AC compressor went bad it would lock the motor. No belt squealing no other sounds.

I edited the first post because it did sound like the engine died, but i know for sure now thats not the case. The line you quoted was deleted and really I should have just had this line
Once it seized while reving it in the driveway, everytime i started it back up, it would stall/seize when releasing the clutch, the only fix was to get out and push the car an inch or two then i could release the clutch and drive it.

Thanks, i will try jacking it up and see if i can move the wheels.

[Oldblueaccord]

I edited the first post because it did sound like the engine died, but i know for sure now thats not the case. The line you quoted was deleted and really I should have just had this line
Once it seized while reving it in the driveway, everytime i started it back up, it would stall/seize when releasing the clutch, the only fix was to get out and push the car an inch or two then i could release the clutch and drive it.

Thanks, i will try jacking it up and see if i can move the wheels.


Any luck with this.

I was thinking maybe its the shifter not put together right or some part missing and its slipping a little as your driving.

I think you are correct to guess its going into 2 gears at once if that is possible on our style trans.

One of my good high school buddies had a 69 Firebird do it quite a bit. I dont think it every did it moving.