transmission

stillfishing
Posts: 5
Joined: Tue Jul 08, 2014 9:31 pm

transmission

Unread post by stillfishing » Thu Jul 24, 2014 8:59 pm

On a 1997 Blazer it was stuck in 4 wheel drive, found that the actuator has vacuum to it all the time. I unhooked the vacuum line and plugged it off. it is in 2 wheel drive now, but the 4WD light is still on. Also I think the shift points are too high, it shifts between 2500 and 3000 rpms.

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carriedi
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Joined: Wed Apr 10, 2013 12:42 pm

Re: transmission

Unread post by carriedi » Fri Jul 25, 2014 11:58 pm

check that the axle is really disengaged from the 4wd solenoid. if the axle is not locked in 4wd then you have a short or a bad switch in the front axle.

do you have a check engine light on?
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stillfishing
Posts: 5
Joined: Tue Jul 08, 2014 9:31 pm

Re: transmission

Unread post by stillfishing » Sat Jul 26, 2014 6:07 pm

there is no check engine light on. it is disengaged, i was going to take out the vacuum switch on the transmission or transfer case and see if it is stuck. what solenoid are you referring too, there is a cable that engages the front differential

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carriedi
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Re: transmission

Unread post by carriedi » Sun Jul 27, 2014 4:29 pm

there should be a switch in your front axle that tells you when the axle is engaged. look at where the actuator is (the part that locks the axle in 2wd or 4wd) the switch is #13. that should be what lights up the 4wd indicator
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stillfishing
Posts: 5
Joined: Tue Jul 08, 2014 9:31 pm

Re: transmission

Unread post by stillfishing » Mon Jul 28, 2014 8:44 pm

I disconnected the wiring to the switch on the front differential and the 4WD indicator light stayed on.

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carriedi
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Re: transmission

Unread post by carriedi » Tue Jul 29, 2014 1:46 am

so it says that you are in 4 high, 4 low?

the light is turned on by the transfer case shift control module. Tan/black wire to 4wd high and purple/white for 4wd low. The module supplies ground in these wires to turn the lights on. the switch supplies power to the transfer case module to tell it what mode you have selected. so, power on the dark green/white wire from the switch is for 4wd low, goes to the C3 pin on the transfer case module. Power on the dark blue wire from the switch changes to a dark green/white wire to pin C4 on the transfer case module is for 2wd high. power on the gray/black wire from the switch is for 4wd high.

check to see which out of the switch is powered up to see if the module is getting the correct signal from the switch
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