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4X4 Issue

  #1  
Old 12-20-2009, 02:27 AM
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Unhappy 4X4 Issue

Last week while wheeling in 4wd hi I blew the rear end in the truck.

Axle know comes out of rear end assembly by hand.

My problem is when i blew the rear i lost my front at same time.

When i engage 4x4 my light comes on the stick.

But i have no front engagement at the chunk.

The front shaft spins but the axles dont move.

What would cause this issue? How do i remedy this?
 
  #2  
Old 12-20-2009, 08:20 AM
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Well lets start by what it is that you are driving... From your avatar, it is not a fullsize so this thread will have to get moved.
 
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Old 12-20-2009, 09:27 AM
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its a 1993 chevy fullsize blazer k1500with 8.5 rear ring gear. 3.42 gears
 
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Old 12-20-2009, 02:52 PM
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Ok. You might want to add that information to your signature, profile, and/or make use of the garage section of the site to make that information known... Your avatar is quite small and difficult to tell the difference between a fullsize and a 1st gen s-series.

Now your problem could quite possibly be with the front axle engagement. The IFS fullsize Blazer's (92+) have a similar setup at the front axle to the s-series. They use either a magnetic actuator or a gear driven actuator to engage the front axle. If this is not engaging, you will get no power to the front axle. The actuator is located on the passenger side of the front diff where the steel extension housing bolts to the aluminum differential center section.
 
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Old 12-20-2009, 03:35 PM
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ok have sig fixed.

would it be the same as this that was posted in 4x4 no worky.

The vacuum actuator is located under or next to the battery. Older trucks have it next to the battery tray. Newer trucks have it under the battery tray, you have to remove the battery and battery tray to access it. Battery tray bolts are above the tire in the fender well.


There is a cable that runs from the vacuum actuator down to the front alxe. The vacuum from the t-case pulls the cable and it engages the front axle. Rare for this cable to break or get stuck, but it happens. A quick easy check to make sure the cable works and the vacuum system is broke. Pull the cable about 1/2"-3/4" and attach a pair of vise grips so it wont retract. Drive the truck and see if the 4x4 is working.
 
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Old 12-20-2009, 03:51 PM
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No. As stated, the new body style fullsize trucks have an electronic (either electro-magnet, or gear/motor driven) on the front axle. The engagement inside the front axle is similar to the s-series, but the way it is actuated is not.
 
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Old 12-20-2009, 03:56 PM
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so then how would i go about testing that?
 
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Old 12-20-2009, 04:19 PM
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Remove it and see if it moves when you put your truck into 4wd... You can also test the wiring at the actuator.

There is a TSB on the original style of actuator that states to replace it with the updated gear/motor driven unit. This requires some re-wiring of things, but is a MUCH more reliable means of engaging the front differential. Check with your local Chevy dealer for part numbers.

The attached image is from the TSB, but should give you the relevant wiring to test.
 
Attached Thumbnails 4X4 Issue-fullsize_actuator_tsb.gif  
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Old 12-20-2009, 04:35 PM
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ty will try and c what happens. will let ya know
 
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