Allison 5sp: 4th gear hold tcm tune

[JustinD]

Hey guys,


I have been looking over on the EFIlive forum and have made the changes that were recomended to hold a 5 speed Allison in 4th for a dyno pull, I have attached it can anyone look over it and see if it looks ok? I only changed the 4-5 shift stuff hoping it works

 

[JoshH]

You need to change the 4->3 downshift stuff too.

 

[JustinD]

Ok, thanks

 

[JustinD]

So just max out the speed/rpm for the 4-3 downshift?

 

[JustinD]

How is this?

 

[Kennedy Diesel]

I went to a 4-G-O tune based on my Race TCM OS. I like it quite well. Just manual down if necessary to get things rolling.

 

[JoshH]

So just max out the speed/rpm for the 4-3 downshift?

I didn't open the tune, but you want to lower your downshift speed and RPM. In order for it to downshift, it must fall below the speed/RPM parameter in the tune, so you need to set it low enough that you won't fall under the downshift setting and set the upshift speed/RPM high enough that it won't go above it. Make sure you change both part throttle and WOT.