So, i've just realised that there is no NSBU switch on the outside of my 2006 Allison... So, they obvioulsy did something different at this time - maybe when they bought out the six-speed (as mine is)...

So is my Ally running with the 'gen4 controls' I occasionally hear about - and this revision does away with the NSBU? Or is the NSBU put somewhere else in the system (in the cab, or maybe inside the transmission)?

Any info much appreciated!

It is inside the pan.

So, i've just realised that there is no NSBU switch on the outside of my 2006 Allison... So, they obvioulsy did something different at this time - maybe when they bought out the six-speed (as mine is)...

So is my Ally running with the 'gen4 controls' I occasionally hear about - and this revision does away with the NSBU? Or is the NSBU put somewhere else in the system (in the cab, or maybe inside the transmission)?

Any info much appreciated!

Yes, 2006 and later has Gen4 controls.
The NSBU function is moved inside and called an IMS (Internal Mode Switch).

I agree with the IMS comment. Further, it seems to have helped, because I've not heard many complaints on the internal switch. It might be a tad harder to get to, but it sure doesn't fail like the propensity of the NSBU.

Thanks for the info!

Anyone know if the Gen4 stuff applies to the Medium-duty trucks as well?
Basically - If i don't see an NSBU where it used to be (on any Allison) does this mean it is Gen4 no matter what?

Thanks for the info!

Anyone know if the Gen4 stuff applies to the Medium-duty trucks as well?
Basically - If i don't see an NSBU where it used to be (on any Allison) does this mean it is Gen4 no matter what?

Yes, for 1000/2000 Series.

you can also just look at the TCM. the wtec gen III allison TCM's are big and have an aluminum case, and two connectors (red/white). 4th gen controls are black plastic with a single 80 pin connector and have a spikey big heat sink on one side. They only say allison on the back. They also say motorola and A40, A41, or A42, depending on wther its a GM pickup or some other medium duty app.

ben