Axle ratio swap
 

The yukon hybrid is finally getting to the age where i can justify messing around with it for a little fun. Does anyone know if the 2ml70 controller can be reflashed for different gear ratios? This truck has always felt like the transmission is just barely holding on to keeping the engine from redline / feels like it's on the verge of slipping into the limiter; depending on the state of the traction battery that's happened more frequently as the battery ages.

But if I've just a slight downhill grade to help the transmission hold onto the hybrid mode 1 it pulls SO much harder & keeps the rpm's locked around 5500 like it feels like it should right up to where it needs to shift modes. To me that says a shorter diff ratio would let the transmission "lock" (i know it doesn't actually lock, that's just the best way to describe how it feels) and would let the 6.0 eat like it wants to instead of sneaking up on the limiter.

So... any idea if these can successfully have axle ratios programmed?

Re: Axle ratio swap
 

the early model caddy came with a 3.42 but there's no way to tune the tranny tcm at all.

when guys regear normal trucks, do they just adjust speed in the ecm using hp tuners, or do they need to go into the tcm and adjust it there for it to shift right? I haven't done it, so don't know.

might go into the ecm with hp tuners and change the speedo reading 5mph different and see if the tranny still shifts right. mine was off 2mph from the GPS speed, so I used hpt to adjust it to match. didn't notice any difference in the tranny thou.

Re: Axle ratio swap
 

Have you ran a report on your HV battery recently?

I tow a steel two horse gooseneck trailer with 2013 Silverado Hybrid all the time. I definitely max push the boundaries of its tow capacity on a regular basis.

My "rebuilt" NiMH battery was regularly revving out to the point I visited a transmission shop. The good part was he has never had to rebuild one of the transmissions from these vehicles.
Downside was that my battery was shot, without throwing any codes.

The Dr Prius lithium battery did very well for me for about 2 years and 75-80k. I had a heating pad under it to pre-warm it for a few hours in sub zero weather. Huge mileage difference on winter trips under 30km.

My Dr Prius Sodium Ion warranty replacement battery works good. It does much better when it's above 15c as well. Once summer hits I can really put it through its paces.

I've driven this truck for about 4 years and 160k now and I honestly don't think that even if you can get it reprogrammed that the gearing will do anything for you.

In my unprofessional opinion, it's all about available kilowatts in the battery pack as these trucks use one of its electric motors where you would normally have a torque converter.
I believe it revs out to create extra electricity to be able to transfer the engine torque to the driveline when the available Kw in the battery is low.

If I knew how to double the battery pack capacity and give it plug-in charging capability when it's parked at the barn, I'd be willing to spend some time and money on it.

Re: Axle ratio swap
 

for me it's those 115 degree days with front and rear ac blasting and battery Temps over a 100 that it starts feeling weak even with a good battery.

cool days with the windows down it's a completely different truck. I've seen over 12amps discharge with the ac on in auto stop, and if you pull up the ac compressor rpm, it does ramp down in auto stop. so probably pulling more running.

Re: Axle ratio swap
 

Have you checked your max temp and cooling fan speed with Torque pro?

Re: Axle ratio swap
 

yeah. I keep an eye on stuff with Torque and I have a tech 2.

by the way, the Dr prius app now supports our trucks