There are dealerships that are on the web that may sell it to you.

 

Ah good to know, thanks! I'll keep this in mind if a battery is definitely needed. At this point, I'm really unsure if the tech was right. Based on what's happening I'm really thinking its transmission related.

 

Hopefully it's not Carbondale cadillac!

 

I just realized this morning that my initial thoughts were slightly off. Its not stalling/ hesitating when it transitions from HV battery to engine only... its also doing this when accelerating from a stop slowly, when the truck would typically stay in hybrid power for up to 20 mph. So the engine cranking is unrelated to the issue.

There are also times when I'm sitting in traffic and what I thought the car was misfiring, it was like sitting in a car with a big cam, where its shaking a bit erratically, feeling like its about to die.

Because of these two points, I'm wondering if its a matter of the trans aux pump or control module. If while in autostop the aux pump is not supplying adequate pressure to the clutches to get the truck going, the car could stall I assume.

Interesting related info about the 2ML70 transmission:

"The 2ML70 transmission is a four speed rear drive which can be configured in a two or four wheel drive application (Figure 1). The 2ML70 does not use a torque converter; it uses a dampener assembly to smoothly transmit power from the engine flywheel to the transmission.

The 2ML70 uses a vane type pump with the dampener housing as the pump body. This system utilizes stop/start technology and therefore has a 12 volt auxiliary pump to keep the 1-2 clutch primed any time the engine shuts down.

The 2ML70 also utilizes three planetary gear sets, two rotating clutch packs and two fixed clutch packs. In addition it has two 60 kW electric motor/generators which can drive the vehicle on electricity only and can also recharge the 330 volt hybrid battery pack.


DRIVING MODES:

ELECTRIC LAUNCH
When the vehicle has an electric launch, the internal combustion engine (ICE) remains off; the auxiliary fluid pump is then used to provide transmission fluid pressure allowing the hybrid low, 1-2 holding clutch to be applied. Drive Motor 2 then completes the powerflow by driving the third position sun gear shaft. Once additional power is required to accelerate the vehicle, the ICE is started initiating the EVT Mode 1 (Low).

EVT MODE 1 (LOW)
When it is necessary to initiate this mode, Drive Motor 1 is used to start the internal combustion engine (ICE). Once stared, it then becomes a generator for the Hybrid batteries. Drive Motor 1 is also used to provide a driveline load during coast conditions to help slow the vehicle. Depending on the driving conditions of the vehicle, the ICE will operate in either 4 or 8 cylinder mode to optimize fuel consumption while maintaining output power requirements.

EVT MODE 2 (HIGH)
As vehicle speed increases, the system will shift to EVT Mode 2. This is similar to EVT Mode 1. The difference is that the Hybrid 2-3-4 clutch is applied rather than the Hybrid Low 1-2 holding clutch.

AUXILIARY FLUID PUMP
The Auxiliary Fluid Pump is a 3 Phase 12 Volt AC motor type that is turned on by the Auxiliary Fluid Pump Control Module (AFPCM) when the vehicle comes to a stop and the engine is off. It provides lubrication and keeps the Hybrid Low-1-2 Clutch applied in preparation for initial take off.

link: http://www.searchautoparts.com/motor...d-transmission

 

There are two 9/16" steel plugs threaded into the transmission bell housing on the driver's side. They are a SAE straight thread and they are for pressure gage testing.

One is for the engine driven main pump, the other for the aux pump.

They are difficult to get to but not impossible.

 

Thanks! Didn't even think about that. I've replaced a few T56 and 4l80 on other trucks, so I'm all too familiar with the tight space near the bellhousing...no fun. I'll have to see if I can find the specs on the pressure of the six pump and see if I can somehow test it in auto stop mode.

 

These fittings are like Allison uses not tapered pipe. I think the top one, harder to get at is Aux pressure.

8 feet of hose and a gage and you can drive it.

 

Awesome thanks Hillbilly. I'll dig through my Chiltons manual and see if I can find what the press should be at auto stop and then while engine is running

 

Remember 2 ports. A shuttle ball rolls back and forth inside to block other. So engine on Aux port off.

Engine off and aux on... other port off. The Engine-to-aux hand off and aux-to-engine hand offs can be clunky if not working right.

 

Thanks. Yes it's extremely clunky right now. When switching from auto stop to engine there is an obnoxious bang every time. I was wondering if there was a shot engine mount or something.