AL5 Tow/haul part of tune wont change but rest of tune will.

Hey Everybody,

Ive got a 2002 LB7 with the AL5. I am tuning my TCM so that in tow/haul mode I can get it to shift into 5th gear later as Im having trouble with it slipping early while pulling trailers. No matter what I set in the tow haul part of the tables the tune still shifts at 57mph which isnt even the stock value? In the normal drive part of the tune the TCM responds to any changes I make such as making it shift to 5th at 80mph but will continue to shift into 5th at 57mph in the tow tune no matter what value I set it to. Any ideas or suggestions would be awesome. I have already reflashed the TCM as well as done the calibration tunes and still no luck. The OS of the TCM is 15079907.

Thanks,
Kyle

Try an 01 OS as it shifts into 5th 5MPH higher than the 02 OS in tow haul mode, and I've found it to shift MUCH more consistently. As to your issue, it is a known issue with the shift tables being labled wrong. Tow haul tables are labled as 4 low(table B), and the 4 low tables are labled as tow haul mode(table 4). And 02 also has errors in the tow haul shift mode tables as they do not match. The tables are scaled to show it to shift at the same speed as an 01(55MPH), but it actually shifts at the speed of the 03-04 OS's(52MPH). This is another reason I do not reccomend keeping the 02 OS, espescially if you want to go changing the shift speeds that aren't even labled correctly to begin with.

All those tow haul, hot trans and 4low patters are all labeled incorrectly. And it varies by OS and table as to which one is what. Unless you have knowledge of how to follow the code in the back-end, your best option is to make changes to the Hot or 4Lo or towhaul to see which one produces the results you're looking for. If those dont work, try the ones with gear selector in 2. There are one or two IIRC that are swapped with those.

Another note... If you find that hot trans makes your changes for one table... Tow haul may make your desired changes for the next table... Like I said. The labeling is all screwed up.

There was to much copy pasta going on assuming all the OS's were the same.