I am having the same problem as others not being able to get lockup until 4th gear on a boosted launch.......I currently have a 1057, which converter is going to make 2nd gear lockup happen?
MikeL, which converter?
- Thread starter DuramaxPowered
- Start date
I just got my trans built and before it would usally lock in 2nd like I tell it too. But know it almost feels like its not locking untill the higher gears, but I havent logged it to see whats going on though.
my 1058 has been that way since day one. I was datalogging within days of the install, at the track about 30 days from the install, and every boosted launch datalog I have (probably 50-60 that I kept saved) all show locking delayed until 4th gear. I thought it was normal until I found out it is not normal.
My 1058 will lock in 2nd gear if I leave at idle and go wot through the gears, but on a boosted launch it will not. Functions completely normal in any other driving conditions.
Jody
It is a common problem for the 1058. There is nothing available in EFI to fix the problem.
nothing in the tune. I've tried the stock tcm tune, several modded ones, and known good lockup race tunes (with other converters), same results. I've also tried stock ecm tunes, tow tunes, and different race tunes (again known to lock second gear on) with every mix of stock to race tcm tunes, same results. I guess I shouldn't say it's not in the tune, I think it can be cured in the tune if we can gain access to the proper tables.
Also, when cruising at say 50 mph, converter locked in 5th gear, you go wot and on the downshift it unlocks. If the slip is beyond 600 rpms it won't re-lock, according to an Allison engineer. Usually mine will re-lock, but sometimes may take several seconds. This is what the engineer told me:
The calibration you have in your truck should stay locked on downshifts unless he crosses the WOT TCC shift line which is set at 49 mph for both 5th and 6th gear. He could be getting into slip float disable cals during the shifts. If there is a speed discrepancy of 80 rpm between engine and turbine during a shift, the TCM will drop lockup. If he is putting a lot of torque into it, that is probably what is happening. That calibration was supposed to inhibit an apply if engine is below turbine by a calibration amount because the A1000 does not have controllable TCC applies when engine is less than turbine speed. We have bumped that calibration up to 150 rpm in MY09. This is not a mechanical limitation. It is probably not relocking because the slip has to be less than 600 rpm before we will try to relock. This is a limitation of the production mechanical hardware (could fail the clutch if you do this maneuver enough times) but I do not know about the aftermarket hardware.
As far as the boosted launch lockup, that's a different problem, but still referenced to excess slip. The bottom line he told me, it's not a mechanical limitation of the trans, they could tune it to command lock regardless of slip. They don't do it to protect the stock single clutch converter. So if EFI Live can find the missing table(s) we'll be able to tune around this issue. If not, we need to swap converters to something like a 1054, or one that will definitely lock up earlier on a boosted launch.
Jody
Last edited:
Wow. Sucks you'll have to change converters because of this. Would have been nice to know before hand but I guess that's how it goes sometimes.
It really sucks to have these problems. If I knew the missing table would get released within the near future, I would leave this converter in.....It's not a big deal to swap out the converter if it will fix the issue for sure
But it may not, even the 1057 users are having issues.
I must have a weird Truck cause it doesnt do any of the common problems. Even with the dual pumps and HTT 66 it would like in 2nd and run like hell.
I will have Terry from PI look at this thread in the am. I have my own ideas but won't talk about it yet.
Post this over on the EFI forum, I know you have posted the troubles of not locking over there but this may be enough proof that there may be some more work needed for the TCM tuning