has anyone played with shift timing?

[sledbert]

Has anyone played with the B5100, 5104, 5108 etc "desired shift timing" tables?
I have built an ECU tune that tows good & pulls like a !*%$&@ at WOT.
Now I would like to tighten up the shift firmness & remove the slush box feeling.
It looks like simply changing the -100 # to say -150 or-200 ??

2008 LMM 6spd
thanks guys
:)

[cmitchell17]

Ive heard its only tuning the shift timing for the oncoming clutch and that it won't have that much of a diffrerence, but I don't see why you couldnt go a little.

[sledbert]

Judging from what EFI has for a description, it looks like these are the lengths of time that the solenoids take to apply/release the clutches in order to shift to/from the next gear.
So..... yeah, it looks like we should be able to make adjustments to the values, the only negative could be a harsh shift.
??

[cmitchell17]

I don't know anything about transmissions but ive seen where people have made tcm tunes and adjusted the shift times by about 50-250ms. I tried adjusting mine in the 70+tps area by about 25-150ms and on I think the 2-3rd shift it does something wierd. So im going to change them back to stock for now.

[sledbert]

thanks, goood to know. I have asked the same question on another forum, I will let you know if I get a response.

[Sparky8370]

I adjusted mine. It seemed to make it feel better without being too harsh. I didn't adjust it too much. You can find my stock tune as well as my modified tune on www.dieseltowingresource.com

[cmitchell17]

Has anybody ever adjusted the TCC duty cycle past where it was stock? What if you made it 100% could you get a little more holding power out of it?

What about disabeling the g-soleniod at a diffrerent rpm? Ive heard the g solenoid lowers the main pressure at low throttle so if you disabled it at a lower rpm it would build more pressure faster?

[Cougar281]

Has anybody ever adjusted the TCC duty cycle past where it was stock? What if you made it 100% could you get a little more holding power out of it?

What about disabeling the g-soleniod at a diffrerent rpm? Ive heard the g solenoid lowers the main pressure at low throttle so if you disabled it at a lower rpm it would build more pressure faster?

You don't want to put the TCC DC to 100%; You'll burn it out because it's not rated for that duty cycle.

[cmitchell17]

Ok thanks, can a soleniod never be at 100%? Is there any benifit to disable the G Soleniod at a lower rpm?

[Cougar281]

Ok thanks, can a soleniod never be at 100%? Is there any benifit to disable the G Soleniod at a lower rpm?

Depends on the solenoid. The TCC one isn't rated for 100%; not sure what the others are. I THINK the G-Sol was put there to get an extra .00000001 MPG for the EPA; I don't think it hurts either way (enabled or disabled).

[cmitchell17]

Ok thanks for the help. I just though you might be able to disable it earlier in the rpm range or disable it all together to get more pressure?

Sorry for all th questions but is there any benifit to adjust any of the other TCC tables or trans tables besides shift points?

[Cougar281]

There may be if you know what you're doing (which I don't); If you tinker with shift timing tables and such, you run the risk of seriously screwing something up (potentially "pick the pieces of your transmission up off the ground" type screwed up).

[sledbert]

I asked the shift timing ?? on duramaxtuner, here is Nick's reply;

"It's a touchy area, you'll find a lot of mixed review on it.
My personal truck has the shift times shorted between 150 and 200 ms from stock. I would work in 25-50ms incriments and be careful!
Hope this helps,
Nick"

[sledbert]

With respect to the TCC Solenoid >? I think another reason that it is pulsed is for the cooling effect.
It allows a small amount of fluid to flow through the clutch during the off segment

[cmitchell17]

Ok thanks but does anyone else have trouble with their tcc lockup at WOT?

I wish there was a way to log it but it dosent feel like my converter locks untill about 50-60mhp?

[sledbert]

I think u'r correct, that there is no PID's or logging for the trans.
However....you can tune the TCC lock-up speed to where you'd prefer it.

Upload the stock trans tune & check the TCC lock-up speed D5014, change it & see what it does & how you like it.
My stock tune in 6th gear wants lock-up at;
50% TPS=74kph , 75%+=85khp (55mph)
does this help??

[Racehemi]

Here are the Allison PID's I have logged

[sledbert]

I have a 2008 with the 6spd Ally, I see the PID's that you have logged when "all" is selected. but when I Tag only the "supported" PID's the list goes to zero. This tells me that the new 6spd TCM isn't monitored. I could be wrong.....

[cmitchell17]

I did not even know you could log PID's from the allison. My labtop broke so I can't check it now but next time ill see when I connect to the tcm see if i can try to validate the PID's. I havent messed with my part throttle lockup I just set the WOT values in each gear to what they were in each gear in T/H.

For thoes with a stock converter and trans what slip are you seeing with higher power tunes?

[Sparky8370]

I have a 2008 with the 6spd Ally, I see the PID's that you have logged when "all" is selected. but when I Tag only the "supported" PID's the list goes to zero. This tells me that the new 6spd TCM isn't monitored. I could be wrong.....
You can only log one controller at a time. Do you have the allison lbz/lmm controller selected?

[Racehemi]

I have a 2008 with the 6spd Ally, I see the PID's that you have logged when "all" is selected. but when I Tag only the "supported" PID's the list goes to zero. This tells me that the new 6spd TCM isn't monitored. I could be wrong.....


Remove the check mark from the Supported box and select transmission in the system box. When selecting PID's do they turn black as in my pic or do they have a red x through them? Do they validate?

[sledbert]

As you suggested...
I double checked the conroler selection= "LLY/LMM Allison"
selected from the system drop down" transmission*
unchecked the "supported" box= all PIDS are still "X"
I tried the "supported" box= no PID"S available.

it looks like the new LMM TCM is nt supported
:(

[Sparky8370]

Can you download the tcm tune?

[sledbert]

do you mean load/copy the TCM tune from the truck? Yes.
I have done that, I've mod'd it & reloaded the new "improved"tune to the TCM
no problems, just cant log data.