Trouble Shifting to 2nd
Thread Starter
1st Gear
Joined: Nov 2015
Posts: 1
Likes: 0
Trouble Shifting to 2nd
Hey Everyone!
I've got an issue with my 78 corvette TH350. The issue I've had for a couple days is the transmission will intermittently shift from 1st to 2nd. The only time I can get it to shift is baby it from a stop, get it up to minimal shift speed, let off the gas, and maybe it will shift. If it does not, it continues to stay in 1st. When it does this, it acts like a manual clutch when let off the gas, meaning it drops to idle, and then I have to bring the engine back up to speed to engage it again.
All other shifting is normal after I get to 2nd. I can get to 3rd no problem, downshift to 2nd no problem, downshift again to 1st and it will be locked in gear and have engine braking effects. There is plenty of power and no slipping in all gears (once I get to them). Fluid is full, clean, and unburnt with no metal flakes coming up.
I have replaced the vacuum modulator and checked everywhere for vacuum leaks with no improvement.
I've considered a governor issue and a valve body issue. I'm wondering what you guys might have to say about it. Thank you!!!
I've got an issue with my 78 corvette TH350. The issue I've had for a couple days is the transmission will intermittently shift from 1st to 2nd. The only time I can get it to shift is baby it from a stop, get it up to minimal shift speed, let off the gas, and maybe it will shift. If it does not, it continues to stay in 1st. When it does this, it acts like a manual clutch when let off the gas, meaning it drops to idle, and then I have to bring the engine back up to speed to engage it again.
All other shifting is normal after I get to 2nd. I can get to 3rd no problem, downshift to 2nd no problem, downshift again to 1st and it will be locked in gear and have engine braking effects. There is plenty of power and no slipping in all gears (once I get to them). Fluid is full, clean, and unburnt with no metal flakes coming up.
I have replaced the vacuum modulator and checked everywhere for vacuum leaks with no improvement.
I've considered a governor issue and a valve body issue. I'm wondering what you guys might have to say about it. Thank you!!!
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Is the cable hooked up to the carburetor and adjusted correctly? And you say you replaced the modulator but did you use new hoses where the vacuum line attaches to the modulator AND the intake manifold? The modulator end hose often falls off if it's oil soaked and the top hose can get pulled off accidentally.
