Rear end gone???

[Adam m]

Okay so I was under my truck doing the front differential bushings and u gotta take off the front drive shaft so I did well it got wedged so I thought, so as soon as I prayed it off my truck starts rolling backwards and right on top of my leg/foot which that's neither here nor there but my question is... Wth?! That should not have done that, and when my wife jumped in it after screaming for 10 minutes for help, she put it in drive and it wouldn't move acted like it was in neutral.. so can someone give me a place to start?? Rear diff, transfer case,? I get 0 codes about anything even closely related and if I have no rear wheel drive it's been like this for monthsssss any help will be greatly appreciated
Oh yeah it's a 07 Yukon Denali xl

 

[mikez71]

AWD differential? Similar to lifting both rear wheels off the ground in park, but you can spin the wheels.

 

[Charlie207]

Did you set the parking brake, chalk the wheels?

 

[strutaeng]

What?! Truck rolled backwards after you removed the front driveshaft and pinned your leg? Are you okay?

Safety first man. Parking brake. Chock the wheels on both sides (front and back) if you are removing the driveshaft, especially if on a slope.

But removing the front driveshaft by itself should not allow to the vehicle to roll backwards unless you had already removed the rear driveshaft and hadn't engaged the parking brake, and you were on a slope. The parking pawl on the transmission is the one that keeps the vehicle from rolling when you throw it Park. That's why the vehicle always seems to roll just a bit after releasing the brake pedal; it's the pawl engaging on the teeth.

 

[Doubeleive]

for future reference
AWD- does not have park (not really) what it does is it binds the front and rear wheels together
lift either end up and the other end will roll away.......
don't believe me? ask the guy above with the crushed foot or go ahead and try it yourself, if you do I would highly suggest you be prepared for the consequence.

 

[Doubeleive]

Okay so I was under my truck doing the front differential bushings and u gotta take off the front drive shaft so I did well it got wedged so I thought, so as soon as I prayed it off my truck starts rolling backwards and right on top of my leg/foot which that's neither here nor there but my question is... Wth?! That should not have done that, and when my wife jumped in it after screaming for 10 minutes for help, she put it in drive and it wouldn't move acted like it was in neutral.. so can someone give me a place to start?? Rear diff, transfer case,? I get 0 codes about anything even closely related and if I have no rear wheel drive it's been like this for monthsssss any help will be greatly appreciated
Oh yeah it's a 07 Yukon Denali xl

normal, AWD will roll away if either end is lifted up, has no real "park" instead it binds the front/rear together
unfortunate way to find out....
ALWAYS chock the wheels and set the parking brake, even then I don't trust 3 tons with my life very much

 

[Adam m]

It wasn't lifted at all I just crawled under it. N all 4 wheels were on the ground now chalking I should've known better but I wasnt expecting that. Yes awd differential. The parking brake wasn't on but it was in Park. That's why im scratching my head like wtf yeah I'm alright could've been A LOT worse no broken bones just a lot of bruising

 

[Doubeleive]

It wasn't lifted at all I just crawled under it. N all 4 wheels were on the ground now chalking I should've known better but I wasnt expecting that. Yes awd differential. The parking brake wasn't on but it was in Park. That's why im scratching my head like wtf yeah I'm alright could've been A LOT worse no broken bones just a lot of bruising

unbolting the driveshaft is no different than lifting the truck up, same difference, same result

 

[j91z28d1]

ouch..


but yes, this is just how the all time awd transfer case works. you have a parking paw in the transmission, not the transfer case. so paw lock the output shaft of the transmission in park. but the transfer case isn't locked. once you took the drive shaft off the front, it is basically in neutral.

best way described it is think of your rear diff of a 2wd. put the truck in park, jack up both back tires and they will turn freely but on the opposite direction. same with the transfer case. you didn't notice but once you popped the drive shaft off, it was spinning the opposite way of the one going to the rear end as it rolled over you.


the other kind of case with 2wd, 4h/4lo 4x4 transfer case it different. when it's in 2wd it shouldn't roll away.