2005 Chevy Trailblazer - 4 Wheel Drive doesn't engage

Reply

  #1  
Old 02-07-15, 12:22 PM
Member
Thread Starter
Join Date: May 2002
Location: Jackson, NJ
Posts: 431
2005 Chevy Trailblazer - 4 Wheel Drive doesn't engage

Always keep switch in A4WD mode (Assisted 4WD) and lately rear end was slipping out on corners when wet. Switched to 4W High, the light changed and sounded like it engaged, but still slipping. Tested on snow, front wheels never engaged. Turned switch to 4 Low, light started blinking on 4 high, but never engaged in low, and light kept blinking. Don't know where to begin, don't want to go to dealer unless absolutely necessary, and would like to have an idea of the problem first. Will be selling truck as we just purchased a new vehicle, but would like the 4WD in working order before selling.

Thanks.
 
Sponsored Links
  #2  
Old 02-08-15, 05:30 AM
Member
Join Date: Jan 2015
Location: USA
Posts: 22
Sounds like the four wheel drive actuator. Should be this Robot Check
 
  #3  
Old 02-08-15, 09:24 AM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,301
I think A4WD is automatic 4WD. It normally drives in one axle on and then when it slips, it engages the 2nd axle. Or so it was on my Silverado which should be very much so same system.
Not sure WHY you drive in 4WD all the time. Unless you are constantly on snow and ice and that allows wheels to slip. See, thing about mechanical transfer case is, you do not keep them engaged unless you have no other choice. Normally you stay in 2HI.
I'd agree that actuator is acting up. Also, far as I remember, there is a procedure to put those into 4LOW and to disengage it.
Also, knowing mine and many other Silvies, transfer case switch goes bad notoriously. Mine went bad at 50 plus thousand miles.
 
  #4  
Old 02-08-15, 02:44 PM
Member
Thread Starter
Join Date: May 2002
Location: Jackson, NJ
Posts: 431
You are correct, ukrbyk, I just called A4WD assisted and not automatic, but it does drive with one axle, and if it slips the second axle engages automatically. If rear axle never slips, wouldn't A4WD essentially be the same as 2HI? If everything is working correctly, this mode would mostly use 1 axle. Since this is my wife's truck, I didn't keep it in 2HI so she wouldn't have to worry about switching in wet/icy conditions.
I don't think there is a special procedure to switch to 4LOW, however, I have never used this mode except the other day when I was diagnosing the slipping issue, and was in Park when switching. I have switched it to 4LOW before, so I know it worked at one time.

Nukegaurd -for a $50 part I will certainly try replacing. I just pulled up a video that showed the replacement on a trailblazer, looked at my truck, and it looks like a fairly simple job. Thanks for the link to the part, it's also much cheaper than the site that has the video.


Thanks.
Dave
 
  #5  
Old 02-08-15, 04:02 PM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,301
I'd have been really careful considering A4WD a "same as" 2HI. Transfer case works differently. Every time I had it engaged on my Silvie, you COULD tell power distribution is on.
Make your own judgement

When to use AWD? [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

When you shift from Automatic or 4-High to 4-Low, the transmission must be in Neutral. Typically, the vehicle can be rolling forward, but at speeds of only 1-2 miles per hour. You can shift from 4-High to 2WD or Auto at any speed.
 
  #6  
Old 02-08-15, 04:38 PM
Member
Thread Starter
Join Date: May 2002
Location: Jackson, NJ
Posts: 431
ukybrk - I guess I never really thought about what the transfer case was doing in A4WD vs 2HI, just assumed the same. Don't know if always keeping switch in A4WD could be harmful or not. Regarding 4LOW, I never switched to this mode while moving, so I think I am ok there, but thanks for the link!
 
  #7  
Old 02-08-15, 05:28 PM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,301
It's definitely strange sensation. When you switch to AWD truck almost crouches, you can tell that something is happening on all 4 corners now. It is my understanding that in transfer case, gears responsible for the front end engage but are not "clutched" so to speak to the transmission output shaft. That clutch/gear is "ready" to engage. Hence you have more h/w involved, definitely less rolling capacity and lower mpg.
Will it hurt or not - I'd say, read on this in truck manual. It should say when and what.

I guess, it's OK to stay in AWD

Automatic Transfer Case
The transfer case knob is located next to the steering column. Use the dial to shift into and out of Four-Wheel Drive. You can choose among five driving settings:
Indicator lights in the dial show which setting you are in. The indicator lights will come on briefly when you turn on the ignition and one will stay on. If the lights do not come on, you should take the vehicle to your dealer for service. An indicator light will flash while shifting the transfer case. It will remain illuminated when the shift is complete. If for some reason the transfer case cannot
make a requested shift, it will return to the last chosen setting.
2 m (Two-Wheel-Drive High):
This setting is used for driving in most street and highway situations. The front
axle is not engaged in Two-Wheel Drive. This setting also provides the best fuel economy.
AUTO (Automatic Four-Wheel Drive):
This setting is ideal for use when road surface traction conditions are variable. When driving the vehicle in AUTO, the front axle is engaged, but the vehicle's power is sent only to
the front and rear wheels automatically based on driving conditions. Driving in this mode results in slightly lower fuel economy than Two-Wheel-Drive High.

4 m (Four-Wheel-Drive High):
Use the Four-Wheel-Drive High position when extra traction is needed, such as on snowy or icy roads or in most off-road situations. This setting also engages the front axle to help drive the vehicle. This is the best setting to use when plowing snow.
4 n (Four-Wheel-Drive Low):
This setting also engages the front axle and delivers extra torque. You may never need this setting. It sends maximum power to all four wheels. You might choose Four-Wheel-Drive Low if you
are driving off-road in deep sand, deep mud, deep snow, and while climbing or descending steep hills.
 
  #8  
Old 02-09-15, 03:50 AM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA
Posts: 44,024
I know next to nothing about chevy 4 wheel drive but if you have limited slip, driving in 4 wheel drive on dry pavement will add a lot of strain/wear and tear to the front end. If it's not limited slip the biggest drawback is fuel mileage.
 
  #9  
Old 04-24-15, 12:15 PM
Member
Thread Starter
Join Date: May 2002
Location: Jackson, NJ
Posts: 431
I replaced the actuator, took about 1 hour. Less than 5 min to remove old actuator, however, had some difficulty threading the screws back in.

Seemed to switch into A4WD and 2HI fine, when switching to 4Lo, it would still blink and not switch over. Then I remembered this MUST be done in Neutral (thanks ukrbyk!)

I haven't had a chance to test it out in wet conditions, but hopefully this resolves the problem. I am now wondering with the old actuator, if it wasn't switching to 4LO because I was in PARK and not NEUTRAL. With old actuator, I definitely heard something switching between 2HI and A4WD, but with the new actuator, I really noticed the "crouching" sensation. I will post update.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes