Hard shifting help needed

[MeanGreenMonte]

Alright so I'm new here and to the g body life. I recently acquired my father in laws 84 monte convertible with a 355 small block and a turbo 350 transmission. The issue is when driving around it shifts from 1st to 2nd really high rpm and hard enough to chirp the tires and same from 2nd to 3rd but not as high rpm. The guy he got the transmission from said he had it rebuilt about 3 years ago. What should I start checking to get it to not break my neck when just driving around. Thanks

 

[lilbowtie]

Check that your vacuum modulator is connected - no broke or deteriorated line.

 

[Texas82GP]

^X2

You should have a vacuum line from the carburetor to the vacuum modulator on the transmission. Stock, the line is mostly a hard steel line with a short piece of rubber vacuum hose on each end. Make sure you don't have a loose or missing vacuum line. On the Th350, the vacuum signal tells the trans how hard you are on the gas. With no vacuum signal (unhooked or leaking vacuum line to the modulator), the trans shifts like you are at wide open throttle, but since you are at part throttle, it results in a harsh shift.

 

[axisg]

did you say Monte Convertible ?

 

[MeanGreenMonte]

did you say Monte Convertible ?

Yes indeed I did

 

[MeanGreenMonte]

^X2

You should have a vacuum line from the carburetor to the vacuum modulator on the transmission. Stock, the line is mostly a hard steel line with a short piece of rubber vacuum hose on each end. Make sure you don't have a loose or missing vacuum line. On the Th350, the vacuum signal tells the trans how hard you are on the gas. With no vacuum signal (unhooked or leaking vacuum line to the modulator), the trans shifts like you are at wide open throttle, but since you are at part throttle, it results in a harsh shift.

I will have to get under there hopefully tomorrow. Thank you

 

[MeanGreenMonte]

Check that your vacuum modulator is connected - no broke or deteriorated line.

I'll take a look under there tomorrow. Thank you

 

[airboatgreg]

As I remember it could also be the manual control valve. Engine off, push gas pedal to floor reasonably hard and rapid a few times. That allows that kick-down cable to move the valve in the transmission and unstick it.

 

[Bar50]

Pics please

 

[Opie Knievel]

Pics please

X10

I have seen one in my entire life. It was on the back of a rollback. I never heard the story on it. I would love to see pics of yours and hear any backstory you know about the car.