TC Lock-Up Switch

TrentNell

Finally underway !!!!!
Jul 7, 2008
7,543
0
0
44
slc tuah
from my logs it seems if the tcc slip speed is greater than 550 or so, the TCM inhibits lockup.

i just reveiwed a log and my rpm slip is under 500 rpm by 30 mph and stays under till it locks.... starts locking @ 47 and is locked by 50 mph or so ? maybe in my case i could cammand it ealier and it may work ?
 

camcojb

New member
Dec 10, 2007
116
0
0
I just wonder if it's a bigger issue with the 6 speed trucks. Are there any 6 speed guys making 550+ rwhp that can get 2nd and 3rd gear to lock at the track?

Jody
 

djms

New member
Dec 25, 2006
263
0
0
Houston tx area
mine is also a 1058. I have tried every trans tune from stock to whatever, will not lock in 2nd or 3rd with a 4wd boost launch. I've finally got it to lock in 4th and 5th, wasn't doing that either from time to time.

As far as an engine tune, running twins I am not even sure it'll run with a stock tune, but I may try today. I have tried several of Robs tunes and they all have the same lockup problem. I have put all the defuel back in also, no affect. I have tried three different operating systems, no affect. I'm confident in his tuning. He has seen these issues also, said the 1058 is one of the most consistent with having the lockup issues when racing, but others are as well.

They will also unlock at a downshift and not re-lock until 4th and 5th gear. This would be like cruising at 50 mph, fifth gear, converter locked. Go wot to pass, downshifts to 4th and unlocks the converter until some period into 5th gear again, even though I've tried lowering the lock applys for 4th (and lower gears). If you prevent downshifting it'll hold lock all the time. Go to tow/haul in 2nd and then go wot at 16-20 mph before it upshifts to third and it won't downshift to first and stays locked through all gear. Check out a datalog and see the several tenths in et this gains, at least on my truck. Would love to get this figured out.

EDIT: Went and loaded a 50 hp tow tune (closest thing to stock I had for my new OS). Did a full throttle launch and it still would not lock the converter in 2nd and 3rd gear, even with wot lockup commanded at 18 mph. Then I loaded the stock Allison tcm tune in with the same tow tune, and same thing, no 2nd or 3rd gear lock under wot from a standing start.

So again, three different operating systems, mild 50 hp to full blown twin race tune, and everything from bone stock tcm tuning to fully modded by me tcm tuning, and the results are always the same; no wot lock in 2nd and 3rd gear when drag racing. Locks perfectly at any throttle less than 100% tp. I'm really leaning towards the converter as much of the issue (1058 in my case) as with the power in the toilet on that tow tune and full defuel it still won't lock up.

Jody

My truck acts the exact same way as what your saying and I have an 04. I've tried all kinds of different trans tunes, no change.
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,701
756
113
Texas!!!
I agree with what Ben is saying. I think the TCM sees too much slip in the converter and prohibits lockup. I think there is something in the TCM that is keeping it from commanding converter lockup with X amount of slip. A looser converter compounds the problem, and it can't be fixed with the TCM tune because the table that regulates it isn't available to us.
 

Dieseldog

New member
Feb 15, 2009
4
0
0
Northern British Columbia
I have a 1986 4X4 with a 383 Stroker, (running on C3) Supercharger, 37" Superswampers, with a 700R4 and 4:10 gears. I have a TC Lockup switch on it. Before installing the lockup the truck ran at 2400 rpm @ 80 km/hour. After installing the switch it barely breaks a sweat, running around 1700 rpm @ 100 km/hour. I don't drive the truck in the winter but when I drive the truck I leave the switch "on" all the time.
 

TrentNell

Finally underway !!!!!
Jul 7, 2008
7,543
0
0
44
slc tuah
Going off what I saw that doesn't seem to fit.

Launching soft I had more tcc slip (higher RPM vs mph) yet it still locked in 2nd. Launching harder I had less slip (lower RPM vs mph) but it didn't lock until 3rd.

the tcm is only going to reference input VS output shaft speed . you have to log it to know if that holds true or not . for mine i need to also log and see when the cammand was given , because the TC slip was under 500 after 30 mph , but if it wasnt cammanded then what ben said may still hold true .... if it was cammanded then its something else keeping it from locking.
 
Last edited:

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
Going off what I saw that doesn't seem to fit.

Launching soft I had more tcc slip (higher RPM vs mph) yet it still locked in 2nd. Launching harder I had less slip (lower RPM vs mph) but it didn't lock until 3rd.

no Dustin you need to log the TCM...

turbine vs. input speed is what I am talking about.

ben
 

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
every built up dmax that Ive seen that has an allison thats anal about lockup, its never been a physical/mechanical problem.

ie; the command is simply not given until ~50mph when the tcc slip rpm gets within an acceptable range.

If EFILive could find this table, we would not need a lockup controller, because the stupid TCM would lock it when its supposed to!

D5072 is sort of on the right track to what we need. Ive played with it and it does make lockup harsher/softer/faster/slower, but there is still one more table that overrides it.

However, im not sure D5072 is labeled correctly. Because of the way the allison works, it doesnt really reference anything in PSI, because pressure is fixed by the converter flow valve; the TCM cant control pressure to the torque converter. So all the values in D5072, I dont think those numbers are PSI. Something else...

ben
 

TrentNell

Finally underway !!!!!
Jul 7, 2008
7,543
0
0
44
slc tuah
every built up dmax that Ive seen that has an allison thats anal about lockup, its never been a physical/mechanical problem.

ie; the command is simply not given until ~50mph when the tcc slip rpm gets within an acceptable range.

If EFILive could find this table, we would not need a lockup controller, because the stupid TCM would lock it when its supposed to!

D5072 is sort of on the right track to what we need. Ive played with it and it does make lockup harsher/softer/faster/slower, but there is still one more table that overrides it.

However, im not sure D5072 is labeled correctly. Because of the way the allison works, it doesnt really reference anything in PSI, because pressure is fixed by the converter flow valve; the TCM cant control pressure to the torque converter. So all the values in D5072, I dont think those numbers are PSI. Something else...

ben

i was looking @ D5072 ealier today ..... anything you have found work well , wasnt shure were to start ( torque amount) to increase the engagement speed a bit ?
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,681
232
63
Fullerton CA
Wonder if we could drop the input speed sensor in a little deeper in the bellhousing to get a better signal.
 

MMLMM

Tunergeek
Mar 2, 2008
4,086
2
38
43
Reno, NV
www.dyncal.com
I had a light wired in (rigged in more like it) at Famoso last year. I was locking in 2nd gear, everything seemed fine. I had a intermittent problem on a run but the rest looked good and lockup looked and felt great. I'll try to get a light hooked up again and see if I am still seeing that. I wasnt really paying much attention to lock up back then as it felt great.


12.7 run, with a 1058, my TCM tuning.

Also I have had people in my truck that have 1058s and they think my truck feels way different than theirs. What did you do differnt to mine Mike :confused: lol
 
Last edited:

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
Mike Im running 4L80 speed sensors in mine. With this refreshed 1057 lockup IS definetly a little faster because the converter isnt loosey-goosey, but still, it sometimes wont lock until 3rd gear.

ben