1996 2dr Blazer 4x4 no work manual floor shift

I have a 1996 2dr s10 Blazer 4.3L automatice tranny. I have a manual lever on the floor console to engage 4x4. The indicator light switches from 2 wheel drive to 4x4 but it definitely is not engaging the front tires. What is the best way to troubleshoot this system. Thanks in advance for the help.

I have the same issue with a '96 and don't see a response to this post. I've read the threads but they all seem related to the dash, electronic type of 4x4.

To recap: I shift the lever to 4hi and even tried 4low - nothing, only the rear wheels. It definitely feels like there is something going on with the transfer case since it did grind a bit when going down to and from low.

Please help!!

This thread is old, its usually best to start your own thread and describe what is going on. Do you get the grinding when your shifting to 4lo? When shifting to 4lo with the manual shifter(floor shifter), the transmission must be in neutral and when your shifting to 4lo, not stop in neutral on the floor shifter, just straight through to 4lo.

On to the problem, shift the floor shifter to 4hi, does the front drivetrain on the display light up? Next is, again shift into 4hi, get out of the truck and try turning the front driveshaft, does it turn. If it turns, you have a transfer case problem that must be looked at, if it does not turn, chances are your transfer case is fine, and you have to look why the front differential isn't locking up. The display part is a tell tale sign. If it doesn't light up, you have a differential engagement problem.

This is usually almost the issue, with this system. At this point, the electronic 4x4 system works the same way. When shifting to 4hi and with the engine running, take a look at the actuator under the battery, it should be pulled in and engaging locking the front diff. Check for vacuum by unplugging the vacuum line hose at the actuator. Shift from 2hi to 4hi, you should get vacuum. If you don't you have vacuum, check your vacuum lines up to the transfer case. If they check out, check your vacuum switch, located on the top of the transfer case. It has three vacuum lines going to it. Unplug it and with the engine running, you should have vacuum going to it from the engine, if this check s out, it most likley the switch itself. If you still have no vacuum, check your line from the switch to the engine for damage.

Hope this helps.

Thanks for the reply!!

The only grinding going into 4Lo was due to my impatience in not waiting for things to slow down before trying it. But it did seem to move properly and "engage" 4Lo.

Yes, the indicators are operating properly and light up as expected which is why I assumed things were working.

My Son has the Blazer right now (we bought it for him to drive to/from school/work) but I'll check out the remainder of the areas you've outlined. My feeling is that it's probably a switch or vacuum line. We've just replaced the rear u-joints and I seem to recall checking the front ones and the drive shaft didn't turn...but I'll check it again.

Thanks again for your response and I'll definitely post what I find out!

if the transfercase is shifting then it will be a vacum issue, there is a accuater up under the battery box, take it off and put ur finger were the vacum line will fit after u push it in and see if it holds it in, if it doesnt then there are vacum hoses going from the trans fer case up to the main vacume hose that conects to the acuater pull them off and see if there is any wear on them