bulldawg
06-17-2009, 01:01 PM
Hey everyone I have a 04' Trailblazer LT, when I have it in 4Hi it will stop and i have to press the gas hard, it feels like the bearings are grinding and rubbing. The shop says GM models are like that, but I don't know does anyone else have this problem? Thanks bulldawg.
the roadie
06-17-2009, 01:23 PM
Welcome! I moved your post to a better subforum.
If you're doing this test on pavement, don't. Especially when turning, the transfer case is locked front and back, and since the turning radius is different, the driveline binds up and you could actually snap something weak like a CV joint. The Owner's Manual and all trailvoy advice is to never run a 4WD test on pavement. Just find some dirt or gravel. Your observations are entirely normal. A4WD mode, on the other hand, will run just fine on pavement because it doesn't share torque from the back to the front until it detects wheel slippage.
It's still a great idea to exercise all the 4WD modes once a month or so to keep it limber and greased up and make sure you discover a failure BEFORE you really need the system in slippery conditions.
For an analysis I did years ago about this phenomenon - see the pic:
http://www.roadie.org/envoyturning.jpg