Quote:
Originally Posted by b3lha
Actually I have another question about the workings of the transmission. Do the shift solenoids do anything when the car is in reverse? I always thought that reverse was 1st gear run through an extra cog to change the direction.
But I noticed that, on my car, clicking the manual button changes the state of solenoids 1 & 2 from "1st gear" to "2nd gear" even when the stick is in reverse.  |
Hi Phil n all, there are two sets of solenoids in the box, Solenoids A, B, C control the effect of Line pressure, AWD pressure and converter lock up operation. Solenoids 1,2,3, control gear selection. The A, B, C solenoids are modulated with a PWM Duty Cycle. Solenoids 1,2,3, are just turn on or off. Not modulated.
The way the solenoids operate the box is like this. First and Reverse are both selected by the Shift lever operating the Manual valve, the No.1 and No.2 shift solenoids don’t really play a part in First or Reverse, they are electrically turned on, but just bleed off pressure. The shift solenoids 1,2 then turned off in turn to control the selection of 2,3,4. The No.3 shift solenoid turns the over-run clutch on to give engine braking, and used to smooth the 3rd to 2nd change.
The A, B, C, solenoids are modulated to control oil pressure. The A controls the Line pressure, and varies between 5% (full line pressure) and 95% (low line pressure). The C solenoid operates the AWD. For the Transfer system, 5% is fully applied clutch, 95% is a free clutch. For the VTD AWD 5% is free clutch, 95% is a locked clutch. The B solenoid operates the converter lock-up clutch, it is not varied as much as A or C solenoids, it is just turned on or off, but the turned on, is modulated, to reduce shock.
Harvey.