Allison Tuning

[kirker912]

I'm starting to see if I can make some improvements to my transmission tuning. There is a lot of information out there about engine tuning and I've been doing it for longer so I'm pretty satisfied there but the Allison info is lacking.

I started playing with shift times but I've heard mixed opinions about that approach. Does anyone have any tips for me? Want to swap files and compare results, run some tests.... let me know.

The biggest thing that I want to stop is flaring of shifts. The worst one is the 3-4 upshift. I can't find the shift time PID in the new version of EFI Live but from the log it looks like it's up around 1second for the 3-4 shift where others are .5 to .75 but that's no PID and judging by the defuel time on my log.

 

[SickLL7Crenshaw]

If your trans in flaring, trying to tune it out is not the correct path to go down. Trans built?If so who built the trans? What were clearances? I've seen ECM tuning cause a trans to shift like shit also. Reason why you think Allison info is lacking on the tuning side is because it's simple...leave the TCM tuning alone besides WOT shift points if you don't want worse problems. You need to figure out why the trans is flaring.

 

[Evan@InglewoodTrans]

You shouldn't have to play with anything to stop flaring shifts. It sounds like you have transmission issues

 

[Evan@InglewoodTrans]

If your trans in flaring, trying to tune it out is not the correct path to go down. Trans built?If so who built the trans? What were clearances? I've seen ECM tuning cause a trans to shift like shit also. Reason why you think Allison info is lacking on the tuning side is because it's simple...leave the TCM tuning alone besides WOT shift points if you don't want worse problems. You need to figure out why the trans is flaring.

Exactly :thumb:

 

[kirker912]

The transmission has a boost lockup valve and a transgo Jr. otherwise it's stock.

I don't feel that it's a hard parts problem because I've seen several of these trucks with same issue. It's not horrible but just enough to bother me.

I can easily see engine tuning causing it. It's making more power at lower throttle positions and lower RPM. Thoughts?

 

[SickLL7Crenshaw]

The transmission has a boost lockup valve and a transgo Jr. otherwise it's stock.

I don't feel that it's a hard parts problem because I've seen several of these trucks with same issue. It's not horrible but just enough to bother me.

I can easily see engine tuning causing it. It's making more power at lower throttle positions and lower RPM. Thoughts?

Flash both stock TCM/ECM tunes back in the truck and see if your problems go away. If they do, that's a pretty good hint it's the tuning causing the problems. Also are those "several" trucks with the same problems tuned and (trans) been worked on by the same people?

 

[kirker912]

That's a good comparison. I'll flash both today and see what happens.

Trucks I'm comparing to are different years, builds, tunes... a relearn helps for a while but slowly starts doing it again

 

[N2BRK]

keep your booger pickers off the keyboard in the shift timing section of the tcm tune. Your wallet will thank me. :roflmao:

 

[TheBac]

From EFILive's get-go, it was always said to never touch shift timing.

 

[THEFERMANATOR]

Theres ALOT of tables they included in the TCM I feel they should have NEVER offerred. Yes those tables are mapped in the tunes for other trannies, but that doesn't mean they should be for a clutch to clutch trans. If you're flaring shifts with a good trans, fix your engine tuning, plain and simple. Messing with shift timing, even copying the parameters from the tow/haul tables over can cost you BIG money$$$$

The best way to explain allison TCM tuning is to lay out 1 page in front of you with tables listed on just 1 side. That is basically what we have with efilive for the allison. Now you may THINK that is everything there is, and those tables are cut and dry. Now lets look at reality. In reality there is about 1200 pages of data in the 5 speed allison tcm(6 speeds have even more). Many of those tables work hand and hand with 1 another, many of these inter working tables you can't even see, nor have any idea they exist, but they may reference part of there algorythim off of data from that 1 page you can see. Now does it sound very smart to go messing with anything on that 1 page when most of those tables work in unison with dozens of other tables you have no idea exist?

So be VERY carefull making ANY changes as a small change in just 1 data field could throw off dozens of other tables, and now your allison is a tie up machine grenading hard parts. So why not stick to fixxing the engine tuning and making sure your trans is right instead of trying to re-invent the wheel. Others have tried it, and we have carbage threads to show what happens by doing it.

 

[WolfLMM]

Evan, isn't it the transgo jr that causes the bump in the 3-4 shift? Or rather it's the mods to the drum but the 6spd already has them factory?

 

[Evan@InglewoodTrans]

Evan, isn't it the transgo jr that causes the bump in the 3-4 shift? Or rather it's the mods to the drum but the 6spd already has them factory?

Drum mods