Transmission question
Thread Starter
Racer
Joined: Jan 2005
Posts: 307
Likes: 2
From: McCordsville Indiana
Transmission question
I just got my 80 coupe back from the trans shop and they told me that there is an electric switch on the transmission that is vaccuum operated which locks up the torque converter but there is no vacuum to the switch,he told me it is ok to drive the car but would suggest I find out the vacuum problem and fix it. I have not begun to look for the problem and maybe someone out there can help. I have found 3 vacuum hoses on the left side of the engine compartment under the fender one of which is taped closed and the others just laying there any ideas what they might be for? The transmission was rebuilt and a new torque converter installed!
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Vacuum does not activate a lockup clutch in an automatic tranny. Hydraulic pressure from the tranny charging pump does it. That signal can be driven by an electric switch or by valves in a valve body (either is internal to the transmission). The signal to drive it can be internal or fed by an external computer.
Racer
Joined: Oct 2005
Posts: 457
Likes: 1
From: Royal Oak Michigan
I have an 80 with 350 auto (now 200R4). I believe there is a vacuum line that runs from the intake manifold (rear of the carb should be a fitting there) to the vacuum modulator. I had a wire that went from the brake switch or line to the tranny on the dirvers side and that is what unlocked your torque convertor when you hit the brakes.
Darrel1.
I have the hard vacuum line if your interested.
Darrel1.
I have the hard vacuum line if your interested.
Racer
Joined: Mar 2006
Posts: 264
Likes: 1
From: west central INDIANA
Look at you emissions decal under your hood if its still there. Their is a switch that is mounted on firewall drivers side between wiper moter & hood spring, it has 3 wires on one end and your vacume hose on the other, any manifold vacume will work for testing it out. but it should not apply till 30 mph. if your still stock this what my 80 has and it works great.
