"Auto" 4x4 systems?

spdemon22

spdemon22

Forum Member
My sister has an '07 Envoy with the Auto 4x4, as opposed to the previous part-time and full-time. In low-traction environments I can hear/feel the front wheels "thunk" into action when the rears start to slide. I have to imagine that rough transition isn't healthy, and I've experienced the same in other vehicles.

Does anybody here know what sort of damage that does to the transfercase?
 
My mom drives a trailblazer.It has four settings 2hi,4hi,4lo, and auto.The first time i rode with her in the winter she had it on the auto mode.Which apparently is 2wd until the rears tires slip then it goes into 4.But oh man does it engage harsh.Same thing you noticed i think, just a decently loud thump. I told her to quit using it and to just use 4hi in slippery conditions.
 
yup. My sister had a ZR2 blazer with the "auto" option. I cant imagine suddenly slamming it into 4wd is good for it.
 
I doubt it does any damage, they've been using those systems for along time. The only transfer case I ever had a problem with was on a '99 Expedition, had the auto function as well.
 
i refuse to use that automatic feature. It seems hard on things and i use 4x4 mostly for braking anyway to keep the front tires from locking. Im glad my truck doesnt even have it.
 
It makes perfect sense, when you switch to 4x4 all 4 wheels need to be going the same speed, so if the rears start to spin then 4x4 engages, sure there will be a "clunk".

--Joe
 
I was never worried about the damage, i was more concerned about the vehicle spinning out from the sudden jerk while the truck was already losing traction.
Like Thomas said, if it was slippery, i just put it in 4hi.
 
Roadrage said:
I was never worried about the damage, i was more concerned about the vehicle spinning out from the sudden jerk while the truck was already losing traction.
Like Thomas said, if it was slippery, i just put it in 4hi.
Click to expand...
Good point, one of the few times ive used it, it almost spun me around when i was pulling out of a driveway.
 
on the auto systems, the front actuator(if equipped)is engaged all the time in A4WD and when the module senses the rear wheels spinning faster then the fronts, a electromagnetically operated clutch in the transfer case engages, powering up the front driveshaft
 
You must log in or register to reply here.
Back
Top