that means my brand new car is 2 years old!

 

Time flies when you're saving gas... :O

 

Guss,

I experienced a lack of torque while backing up on a steep hill at the time. The RPM was around 2,000 but only to charge and to make up for the loss juice. I tried the 4x4 mode and turned off the traction control since it was inconvenient at that point. And no improvement "I mean the wheels couldn't be turned by the electric motor".

I was finally able to turn around and gain the help of my 300 horses to get some of my dignity back.

Conclusion: The torque supplied by the electric motors alone is not enough to pull the truck back on a hill steeper than 35 degree.

 

Omar,
glad to hear from you.
Omar is the person who experienced the stalling issue.
Now you can bombard him with all the questions
good luck Omar

 

Omar: were you in 4 WD hi or low? 4 Low has about 2.7:1 gear reduction so in low you should have more than enough torque. Forward the 2 Modes are limited in reverse to about 75% of the maximum forward trans output torque.

Now if we could just get the ICE to make torque while running backwards it would be symetrical.

Next time while nobody is looking give low a try.

 

Hill-billy,

No one was looking beside my wife who bragged about it for weeks.
I only tried the low gear during the circumstance. It felt like ICE was not engaged mechanically. 2500 rpm was the highest i have seen when I floored it. And yes, the 4x4 orange light was on after it stopped blinking which means the gears where engaged.

I have only heard it once from someone who was experiencing similar scenario forward as well. but his truck diagnosed with a bad rear end modular!

I strongly believe the ICE had no roll in making any torque while running backwards other than charging.

PS. If you are one of the designer team then I will take that back and I will consider that experience with my wife that day was nothing but another dream gone bad.

 

You should have been able to make that grade if everything was at full capacity, although 35% is rather steep. But different parts of the typical hybrid drivetrain can overheat and limit capacity temporarily. The batteries, motors, high voltage electronics all have self-protect features. If it was a hot day, if you had already been working the motors hard prior to this attempt, if your radiators up front were clogged with a lot of dust, if your battery state of charge was low to start with, etc. A combination of a few of these would explain why you might have been power-limited for some reason.

 

Hi Guys,

I am new here and first off want to sell hello to all!

I own a 2009 yukon hybrid 4x4. I also had a similar issue with reverse. We had some snow about two weeks ago (roughly 6 inches). I have a pretty steep and long driveway and it was partly shoveled. I had my yukon in 4 wheel high (it was def in 4 wheel mode, I drove home like that), while attempting to reverse up the driveway. I tried everything and cold not get up the driveway. I even gave my self about a 10ft head start and still got half way up with the tires spinning. I turned the car around and went up forward with no issues. Does the 4 wheel even work in reverse? It def did not seem like that was the issue.


Thanks,

Jeff

 

Hi Jeff, I think this post is primarily about not enough power from the 2 electric motors (EV mode) (that is the only power in reverse, the engine does not assist in hp/torque, just battery charging and runs for safety reasons) when backing up. The thread contains statements that the tires are not slipping. I do believe you have 4 wheel traction in reverse but just EV mode and you mention tires slipping. That would be an issue with a conventional vehicle as well. Two thought here however. First, the tires are designed with a tread pattern to provide traction going forward. Second, these are low rolling resistance (LRR) tires and they do not do very well in contaminated conditions. Many folks get a second set if they face contaminated roadways. I back up my drive, which is pretty steep with a 5000# boat behind the truck, so I know the truck can do it. Hope this helps but feel free to narrow the conditions if I didn't answer very well.

 

You are in 4WD when selected in reverse. The factory supplied tires do not have very good traction in slippery, snowy, icy, muddy conditions. Canuck has put Blizzacks on his truck for the winter and it would be interesting to know what his expereiences have been in reverse. I am still thinking of snow tires or off road tires. I know Jet 1 is looking into tires as well.