Please explain to me how the whole 700 auto tranny works like what does the torque converter do etc. I am a complete idiot when it comes to automatic trannys because i am only 17 and i have only been dealing with clutches, pressure plates throwout bearings etc. basically i want to know how a auto tranny works and what the torque converter does. Please help me

THANX IN ADVANCE

 

Here is the Readers Digest version. The Torque converter does the job of the clutch as far as initial engagement goes and transmitting power to the tranny. It "slips" at low RPM and as R's increase it "grabs" more until it can't slip W/O moving the car, this is stall speed. It does this through the use of two oil fans, one driving the other, and another one (the stator) that redirects it back to the others to multiply the torque. It also has a clutch that engages at higher speeds to eliminate any slip inherent in the torque converter.

Inside the transmission is a control system (Valve Body, Governor and Pressure Control Valves) that decides when and how to shift according to gear position, throttle position and vehicle speed. WIth more throttle (greater acceleration and torque) the shifts become more delayed and are completed at higher apply pressures. In a 700 there are several clutch packs and a band that, by holding and/or driving different geartrain components, provide four forward gears and one reverse. These are activated by the control system. The geartrain consists of two planetaries, one in front of the other (Simpson gear design) that drive the output shaft (which drives the driveshaft). They are called planetaries because they have a Sun Gear in the center, and idler gears that rotate around the sun gear, and a ring gear that surrounds those.

Does that help any?

 

alot thanx leo. I have an 86 trans am with the tpi and i am swapping in a 350 tbi because i want to just deal with carbs and not individual fuel injectors. Somone was talking about the torque converter not locking?? can you explain to me what that means and what i can do to fix it??

Brett

 

At @40-45 MPH the clutch in the TC is engaged by a signal from the ECM. W/O this happening the tranny will run hotter and eventual failure will occur (BTDT). This is worse with the higher geared cars. If you have lower gearing it will last longer. Either ECM setup should enable L/U as long is all is working properly.

 

alright thanx leo
btw what is your email

 

lschneg1@rochester.rr.com

Put: Tranny Help as the subject.