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Help Support Hardline Crawlers :
Auto Transmission Tech
- Thread starter Lead Foot
- Start date
These are some of my thoughts that I have been going through for anyone interested.
I'm working on this electronic shifter for the AW4. The shifting will work properly. I will also have a switch to energize the torque converter lock up solenoid. The goal is to be able to run through the gears while leaving the shifter in "drive". Then lock and unlock the tcc as needed.
Others have done simple variations of this but they have reported only true engine braking in 4th and 3rd with the shifter in "Drive" and only 3rd with the shifter in "3" and only in 2nd with the shifter in "1-2". The manual even specifies it here.
Now after doing a whole bunch of reading it seems that the main internals that control the TCC are Sol 3 (which I have electric control of) and the lock-up relay valve (that I don't know much about).
My thought is that the relay valve must not be letting the hydraulic fluid pass depending on what position the solenoids are in? What do you think about modifying that valve to always allow flow? The below picture might help draw a conclusion. I don't really know how to read these schematics.
Is there a reason why I wouldnt be able to completely control it with sol 3? Energize/open it and it lets fluid by to lock the clutches and TCC; otherwise it is closed... This is all just a theory.
My other thought is what if its not the torque converter that is really causing the lack if engine braking? What if the torque converter is indeed locking, but the bands aren't keeping the planetary and sun gears locked and therefore creating a "coast" situation.
Check out this chart. Would it bring light to my above thought at all?
To the above thought, the bands for each gear have to be applied if I'm able to hit the gas and move forward right?... Maybe they are directional? Or at a lower RPM there isn't enough pressure to hold them? The only signals the TCM sends to the trans are Sol 1, 2, and 3. Sol 1 and 2 determine gear. Sol 3 is lock up. I know for sure that the brake pedal switch sends a signal to the TCM and the TCM unlocks the converter using Sol 3. I don't see how it would have control over unlocking the bands in that case....
I'm working on this electronic shifter for the AW4. The shifting will work properly. I will also have a switch to energize the torque converter lock up solenoid. The goal is to be able to run through the gears while leaving the shifter in "drive". Then lock and unlock the tcc as needed.
Others have done simple variations of this but they have reported only true engine braking in 4th and 3rd with the shifter in "Drive" and only 3rd with the shifter in "3" and only in 2nd with the shifter in "1-2". The manual even specifies it here.
Now after doing a whole bunch of reading it seems that the main internals that control the TCC are Sol 3 (which I have electric control of) and the lock-up relay valve (that I don't know much about).
My thought is that the relay valve must not be letting the hydraulic fluid pass depending on what position the solenoids are in? What do you think about modifying that valve to always allow flow? The below picture might help draw a conclusion. I don't really know how to read these schematics.
Is there a reason why I wouldnt be able to completely control it with sol 3? Energize/open it and it lets fluid by to lock the clutches and TCC; otherwise it is closed... This is all just a theory.
My other thought is what if its not the torque converter that is really causing the lack if engine braking? What if the torque converter is indeed locking, but the bands aren't keeping the planetary and sun gears locked and therefore creating a "coast" situation.
Check out this chart. Would it bring light to my above thought at all?
To the above thought, the bands for each gear have to be applied if I'm able to hit the gas and move forward right?... Maybe they are directional? Or at a lower RPM there isn't enough pressure to hold them? The only signals the TCM sends to the trans are Sol 1, 2, and 3. Sol 1 and 2 determine gear. Sol 3 is lock up. I know for sure that the brake pedal switch sends a signal to the TCM and the TCM unlocks the converter using Sol 3. I don't see how it would have control over unlocking the bands in that case....
Last edited:
BUILTnotBOT
Well-Known Member
No real advice to add but if it was me I would be shooting emails to the guys at radesigns
http://www.radesignsproducts.com/
They seem to have the aw4/a340 shifting game down and could probably point you in the right direction.
Its a ways away but I plan on using the aw4 trans in my build. Please update on any info you can track down. GOODLUCK :beer: :awesomework:
http://www.radesignsproducts.com/
They seem to have the aw4/a340 shifting game down and could probably point you in the right direction.
Its a ways away but I plan on using the aw4 trans in my build. Please update on any info you can track down. GOODLUCK :beer: :awesomework:
I know Rory at rad designs. He has a decent Mechanical/switch operated shift for the AW4. I have built a tiptronic PLC based shifter with digital read out. The shifting is not the issue, mine operates just like rad designs. My tcc lockup also will also work like Rad Designs. I plan on taking a whole step further that no one else has done. Modified throttle body for true tcc lock up and engine braking in EVERY GEAR, even first. This is not possible with any existing setups with the stock throttle body.
