yeah, im gonna start ANOTHER thread on this, I found something kind of interesting today in playing around.
If you sit in drive (1st gear) and you apply the converter clutch (either by grounding the f-trim solenoid or commanding it with a Tech 2/efilive), nothing happens. The solenoid lights (as confirmed by my lockup LED) but nothing happens. If you release the brake, and accellerate, it shifts into second gear, then a second later, the converter clutch comes on.
No 1st gear lockup, but we already knew that. People said 1st gear lockup isnt hydraulically possible in the allison
Brayden claimed 1st gear lockup WAS hydraullically possible, but in order to get it you had to be in second gear, apply the converter clutch manually (tech 2 or ground the solenoid), then downshift to 1st gear manually, and the converter clutch will stay applied and you'll get 1st gear lockup.
Well no that doesnt work. I tried it on 2 trucks....
What DOES work...is if you sit in neutral, apply the converter clutch (works both ways, with a tech 2 and grounding it manually), wait a second to give the converter clutch a chance to apply, THEN shift into drive. The truck will move forward a couple inches then BOOM a split second later the converter clutch locks in 1st gear. I know it actually works because after that split second pause of shifting from neutral to drive, I felt the truck quickly load up and the engine immediately stalled (duh).
Ok so thats neat...it works with the tech 2 too, btw, theres no "safety" lockout to prevent you from doing this (shift to neutral, command lockup, shift to drive), which surprised me because normally the tech 2 wont let you do anything "dangerous" or stupid.
BUT when you do this (the little 1st gear "back door" trick), the converter only stays locked for 2 seconds or so, then unlocks itself. Yes, the solenoid continues to stay lit, but something mechanical/hydraulic in the trans releases the converter clutch after being locked for 2-3 seconds in 1st gear. I was on my driveway (our driveway is long), in neutral, commanded lockup, shifted to drive, truck lurched forward as the converter locked up and I accellerated at the same time, then a second later the clutch unlocked until it shifted into second, then 1-2 seconds after it shifted into second, it relocked and stayed locked.
This is NOT a tech 2/TCM/electrical thing, because the f-trim solenoid stayed lit the entire time, it is some goofy hydraulic thing going on inside the trans that makes it act this way. Why? I dont know. But I thought it was cool.
ben
If you sit in drive (1st gear) and you apply the converter clutch (either by grounding the f-trim solenoid or commanding it with a Tech 2/efilive), nothing happens. The solenoid lights (as confirmed by my lockup LED) but nothing happens. If you release the brake, and accellerate, it shifts into second gear, then a second later, the converter clutch comes on.
No 1st gear lockup, but we already knew that. People said 1st gear lockup isnt hydraulically possible in the allison
Brayden claimed 1st gear lockup WAS hydraullically possible, but in order to get it you had to be in second gear, apply the converter clutch manually (tech 2 or ground the solenoid), then downshift to 1st gear manually, and the converter clutch will stay applied and you'll get 1st gear lockup.
Well no that doesnt work. I tried it on 2 trucks....
What DOES work...is if you sit in neutral, apply the converter clutch (works both ways, with a tech 2 and grounding it manually), wait a second to give the converter clutch a chance to apply, THEN shift into drive. The truck will move forward a couple inches then BOOM a split second later the converter clutch locks in 1st gear. I know it actually works because after that split second pause of shifting from neutral to drive, I felt the truck quickly load up and the engine immediately stalled (duh).
Ok so thats neat...it works with the tech 2 too, btw, theres no "safety" lockout to prevent you from doing this (shift to neutral, command lockup, shift to drive), which surprised me because normally the tech 2 wont let you do anything "dangerous" or stupid.
BUT when you do this (the little 1st gear "back door" trick), the converter only stays locked for 2 seconds or so, then unlocks itself. Yes, the solenoid continues to stay lit, but something mechanical/hydraulic in the trans releases the converter clutch after being locked for 2-3 seconds in 1st gear. I was on my driveway (our driveway is long), in neutral, commanded lockup, shifted to drive, truck lurched forward as the converter locked up and I accellerated at the same time, then a second later the clutch unlocked until it shifted into second, then 1-2 seconds after it shifted into second, it relocked and stayed locked.
This is NOT a tech 2/TCM/electrical thing, because the f-trim solenoid stayed lit the entire time, it is some goofy hydraulic thing going on inside the trans that makes it act this way. Why? I dont know. But I thought it was cool.
ben
