Allison Trans Slippage

I have 2008, 2500HD Duramax/Allison, crew cab, long bed, 4X4, with the banks Econo tune with PDA, air filter and cat back exhaust. What I have noticed in that when in 6th gear and the PDA says TCC%on = 100%, which I assume in the lock up torque converter in 100% locked but while traveling at 70 MPH at 1700 RPM, the PDA TRANS SLP say 13 – 18, which I think means the transmission is slipping 13 – 18 %. This happens no mater what level your in on the Banks. Why is the trans slipping at all if the torque in locked? Is this normal?

Thanks

What's Banks have to say about this?

Jim

I sent them an email, before the holiday and I will be calling them on mon. I will let you know what they say.

here is the reply from Banks.

The 13 -18 that you are seeing on the PDA’s display is not representative of percentage of slip. It represents the RPM differentiation between engine speed and transmission speed. This is fairly common and can increase on acceleration or deceleration. These numbers can also appear higher in the event the stock tires have been replaced with a larger or smaller tire size. This is no cause for alarm. If the transmission slipped beyond 3%, the tuner would shut itself off. This is a fail-safe built into the product.


and I have larger tires..

So why measure/calculate/display slip if it's not accurate or meaningless?

How do tires affect the relationship of engine speed versus trans speed and IF this impacts why wouldn't they incorporate a tire size input in their wiz-bang pda interface?

My preference these days is REAL gauges and REAL tuning. Things just work better this way than the old fooling method.