Allison 5sp: Lockup in 2nd gear?

[THEFERMANATOR]

Like many here, I had the dreaded no lockup until the top of 3rd, or 4th gear. Due to my swap, the only OS that plays nice is the 01 15175854 OS, and that is the OS that doesn't have the slip limit tables mapped. I've contemplated a lockup box, but it just isn't in the budget, and I don't race the family truckster(anymore). I have tried the 02 15172881 OS, but it just doesn't play nicely, and even with the slip limit tables maxxed out, disabled, you name it, I still couldn't get lockup until top of 3rd or 4th gear. I was doing some other work to my tuning with the help of chavez91 to take care of another issue I hadhug:THANK YOU, THANK YOU, THANK YOU), and decided to try something to maybe help with my lockup issue.

I went in and lowered D5064 4MPH for 2nd and 3rd gear(don't want to lower it to much or else you could bring the RPM's down so much as to bring you off the turbo), and I now get CONSISTENT lockup in 2nd gear at that MPH. Before I was going into 3rd at the desired 28MPH lockup speed(the TCM thinks it has 4.11 gears and 245/75/16 tires, so actual vehicle speed was 33), so I lowered it down to 24 MPH, and I now hit lockup at around 29 MPH, and drops the RPM's down about 800 RPM's(a bigger drop than the 2-3 shift). So I'm looking for somebody else with bigger HP than me to try this out and to see if this works for others with the 01 OS(and maybe others who still couldn't get lockup after changing the 600 RPM slip limit). I couldn't find any mention of anybody adjusting D5064, so I couldn't find any other references to anybody else trying this. Hoping this might help others like myself who want lockup in 2nd, but don't have the coin for a lockup box.

 

[Chavez91]

Glad I could be of help :hug:

I'll figure something out as far as releasing the tables I gave you as soon as I get the rest of the OS's mapped.

Its funny that you mentioned it as we were talking, because I was testing the same thing.

I have been testing some slightly different values from you, but along the exact same lines using the D5064 table and have achieved a pretty consistent beginning of 2nd gear lockup using the 15175854 OS over the past week. I'm gonna try to convince James to test it in the Limo later this week to seal off my last 0.9% confirmation that the "600 RPM TCC Slip limit" tables that the other OS's have, DO NOT exist in the 1517584 OS. Hense why they were never mapped and never will be mapped.

But I'm definitely interested to see how the Higher HP trucks react to it and if it remains as consistent as it does for us!

Here are some of the Lockups. As you can see, it starts commanding TCC lock just as its finishing the 1->2 shift.

 

[juddski88]

Nicely done!

 

[THEFERMANATOR]

I know getting lockup in 2nd has sure helped mine out. My BIURB used to really take off around 60 when it locked up and hit 4th gear, now it raises up the front end and just PULLS steady from about 29MPH on up. I'm tempted to try lowering the lockup point for 2nd, but I'm worried the RPM drop might be to much. I'm dropping about 700-800 RPM's now from 3200 to 2400-2500 RPM's when it locks in 2nd, and I can see boost drop down some during the drop. Even with a trailer on the back it locked up in 2nd, and I took off and left traffic behind. And I think this is why several who changed the slip limit tables still didn't get lockup was they were shifting into 3rd before the set lockup speed.

THANK YOU again for those other tables, lockup at slower speeds is so nice to have.

 

[IOWA LLY]

In my experience I've never seen evidence that the slip limit tables exist in OS 15175854.

I have experimented with every tcm OS I could find for a 5 speed and this is the only tcm I have found to lock the converter with complete disregard to slip rpm. All others had the 600 rpm limit. And none of the tcm OS will command the converter to lock if it's trying to make a shift. Once it's locked it doesn't care. But I've seen it abort lockup once a shift is commanded if the slip rpm isn't nearly zero....

BTW, Ive seen it command lockup back in the day with over 2000 rpm of slip. In my pulling truck with a very high stall converter of course.


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[Chavez91]

And none of the tcm OS will command the converter to lock if it's trying to make a shift. Once it's locked it doesn't care. But I've seen it abort lockup once a shift is commanded if the slip rpm isn't nearly zero....

James Carter has been testing a few changes for me over the past few days, and It's been working great, but then he hooked up to the 5th wheel to go to Moab.... hahaha! Waiting for him to figure out how to get logs :rofl: but it seems like its hit that exact problem, slip is too high going into the shift and its just aborting lock and by the time it tries again the next shift is happening. Gonna try to get logs of him with the 5th wheel and see if I can find the source of that and if I can stop it from aborting the lock.

 

[THEFERMANATOR]

Theres a setting for lockup during a shift, maybe enable it and see if that does it.

 

[duratothemax]

Ive had D5064 set super low (17mph) forever and still could never get it to command TCC until sometime in 3rd gear.

Thats why its always annoyed me, because 5854 shifts awesomely in my truck, but doesnt have any of the advanced lockup stuff...the other OS's that have the lockup stuff shift like crap on the 3-4 in my truck.

 

[IOWA LLY]

Lower your 1-2 shift down so there is a longer period of time between it and the 2-3 shift. You can also increase the 2-3 shift to a higher mph and RPM to do the same thing. Depending on what your truck requires.

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[fastpunker]

Glad I could be of help :hug:

I'll figure something out as far as releasing the tables I gave you as soon as I get the rest of the OS's mapped.

Its funny that you mentioned it as we were talking, because I was testing the same thing.

I have been testing some slightly different values from you, but along the exact same lines using the D5064 table and have achieved a pretty consistent beginning of 2nd gear lockup using the 15175854 OS over the past week. I'm gonna try to convince James to test it in the Limo later this week to seal off my last 0.9% confirmation that the "600 RPM TCC Slip limit" tables that the other OS's have, DO NOT exist in the 1517584 OS. Hense why they were never mapped and never will be mapped.

But I'm definitely interested to see how the Higher HP trucks react to it and if it remains as consistent as it does for us!

Here are some of the Lockups. As you can see, it starts commanding TCC lock just as its finishing the 1->2 shift.

Way to go chump.... its awesome seeing you find and do this stuff, especially when its almost the same chit I do for Chrysler lol. Post up the pics in a different format.. damn work computer security bs wont let me see that format lol. I'll see ya here shortly and I'm sure we'll talk till neither one of us can anymore :roflmao:

 

[Chavez91]

Note to self: don't divulge any FCA secrets on forums; it'll get Jon in trouble cause he is on the company computer. Lmfao!

Do I need to draw that chet in paint for you? Lol My artsy skills suck ballz, just so you know. I might be headed to Mikes this week if you wanna tag along. Plenty of time to talk on that drive. That's if you can hear over that billet S472. Lol!


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[Chevy1925]

Note to self: don't divulge any FCA secrets on forums; it'll get Jon in trouble cause he is on the company computer. Lmfao!

Do I need to draw that chet in paint for you? Lol My artsy skills suck ballz, just so you know. I might be headed to Mikes this week if you wanna tag along. Plenty of time to talk on that drive. That's if you can hear over that billet S472. Lol!


Sent from my Nexus 6 using Tapatalk

dylan has you taking her out there before NHRDA then eh? sweet!


btw, lock up is still inconsistant on a higher hp truck. sometimes it works, sometimes it doesnt. it really doesnt work when you load the truck down with a trailer and get on it :angel:

 

[duratothemax]

btw, lock up is still inconsistant on a higher hp truck. sometimes it works, sometimes it doesnt. it really doesnt work when you load the truck down with a trailer and get on it :angel:

Even with Josh's latest tweaks?

 

[Chavez91]

Even with Josh's latest tweaks?

Its better, but I need to find what's causing it to abort lock if it hasn't completed by the next shift.

Iirc, James's truck will lock normally, but if he throws the 5th wheel on, he can generate enough slip to cause it to abort. Unless you haven't told me its not locking without the trailer too. But been to busy this past week to really mess with it anyways lol

Were gonna get some logs when you're on the way to NHRDA, gotta confirm. Teach you how to set up that v2 BBX. lmao

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[Chevy1925]

Even with Josh's latest tweaks?

yup. it got real annoying trying to pass on a two lane highway and blowing through the MLG converter . it will do like Tim says too, if your locked and roll into it hard without a down shift, it will unlock the converter every once and a while on an up shift.

from a dig, its 50/50 whether it locks. if i hold traction, it wont lock till mid 3rd gear. if i spin the tires some, it will lock so Josh thinks there is a table or value somewhere

Its better, but I need to find what's causing it to abort lock if it hasn't completed by the next shift.

Iirc, James's truck will lock normally, but if he throws the 5th wheel on, he can generate enough slip to cause it to abort.

Were gonna get some logs when you're on the way to NHRDA, gotta confirm. Teach you how to set up that v2 BBX. lmao

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that wasnt even with the 5th! lol it was just the flat bed with the tracker on the back so i was probably 13000-13500 gross.

 

[THEFERMANATOR]

This is why I wanted to have somebody with some hp to try it out. I know mine is work great now locking right around 30 where I set it to whereas before I wouldn't get lockup till almost 60. Makes a BIG difference when towing my boat(i don't put it in tow haul for anything 5k pounds or so) getting lockup when I have to get on it to pull out. That shooting up to 3000+ and staying there didnt do much when towing.

 

[Chavez91]

yup. it got real annoying trying to pass on a two lane highway and blowing through the MLG converter . it will do like Tim says too, if your locked and roll into it hard without a down shift, it will unlock the converter every once and a while on an up shift.

from a dig, its 50/50 whether it locks. if i hold traction, it wont lock till mid 3rd gear. if i spin the tires some, it will lock so Josh thinks there is a table or value somewhere



that wasnt even with the 5th! lol it was just the flat bed with the tracker on the back so i was probably 13000-13500 gross.

And this is why I had you test it! Lmao. Back to that POS code I guess..... After NHRDA!

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