4X4 transfer case issues

LSC9901 · #1 02-18-2005, 03:17 PM

I have a 96 Blazer. It has a lever switch inside to change from 2WD to 4 WD. The indicator light shows that it is engaged in 4 WD but in reality it is not. I've been told that it is the vacuum switch. Unfortunately I am working off of ramps and I cannot see the switch and have no idea where it is located other than on the top of the transfer case. Does anyone/everyone agree that the switch is probably bad? The front drive shaft remains engaged all the time but the front wheels are not engaged. There is an electrical switch that lights up the two front wheels on the interior indicator when it is in 4 WD. As noted it is on all the time. Obviously when I disconnect the electrical switch the light goes out. Any help would be appreciated. Also does anyone know where I can find diagrams on line showing the transfer case and all of its switches etc. Thanks

ricksza · #2 02-18-2005, 07:11 PM

When you shift the transfer case into 4X4, the vacuum switch on top transfers vacuum to the servo under the battery which pulls a cable to engage the syncro on the axle shaft to lock it in. the vacuum switch gets it's vacuum from the rear of the upper plenium above the distributor. The vacuum switch is the most common problem if you have vacuum to it. If you reach above where the front driveshaft connects to the transfer case, you should feel it or at least the vacuum hoses. You need a 7/8" wrench for the switch.

s10blazerman4x4 · #3 02-18-2005, 07:25 PM

yeh i just had mine fixed. You will have one hell of a time with ramps best bet is don't get frustrated have a mechanic put it in for you. Now i have 4w4 all the time. I was told by the mechanic he had to get out the ol bar because it was in there so tight.

LSC9901 · #4 02-18-2005, 07:34 PM

Is it posible to access the transfer case by removing the front left wheel and moving the inner shroud ???

ricksza · #5 02-18-2005, 07:37 PM

The transfer case is behind and to the left of the transmission. You have to go from under.

LSC9901 · #6 02-20-2005, 07:04 AM

Is there some type of adjustment for the electrical switch that indicates the 4 wheel is engaged? The lever cable that actually switches from 2 to 4 WD connects to the transfer case and at the point it connects the electrical switch is right there. I took the electrical switch off and found that it is a ball switch which is activated by movement of the cable ????

blazee · #7 02-20-2005, 08:02 AM

Maybe I am misunderstanding this thread...are you saying the 4wd works and wil actually shift in and out of 4wd, but the light shows 4wd all the time?

LSC9901 · #8 02-20-2005, 04:02 PM

Quote:

Originally Posted by blazee

Maybe I am misunderstanding this thread...are you saying the 4wd works and wil actually shift in and out of 4wd, but the light shows 4wd all the time?

Yes that is correct. The front drive shaft remains engaged but it isn't in 4 WD. My concern at this point is .... is there an adjustment for the indicator that shows that it isn't in 4 WD?? I know it sounds confusing and yes it is but I'd just like the interior indicator to reflect what is really going on. As I stated the drive shaft remains engaged but the front wheels definitely are not being powered so I just want the indicator lights off when the lever is in 2 WD. Thanks

blazee · #9 02-20-2005, 05:16 PM

Okay so this isn't a 4wd problem, it is an indicator light problem.

I'm not sure of the specifics with this part of the truck, but maybe I can be some help. When you had the switch off, did you test it to make sure it still works? Can you activate it yourself and tell if the light turns on and off?

LSC9901 · #10 02-22-2005, 12:48 PM

OK ... so here is where I am at for now. I took out the electrical ball switch and operated it manually and the switch works fine. The indicator goes off and on as it would if it were shifting from 2 to 4 WD. Once again the actual shifting is happening. My shifter is a mechanical lever versus the push button. While the switch was out of the transfer case I had someone move the lever. I put my finger in the place where the ball switch goes and couldn't feel any movement. I was in hopes that I could feel a movement in there verifying that whatever it is that actuates the switch was actually moving. Where should I look now???

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