97 silverado wont shift into 4 wheel drive

hi
my 97 chev with 350 and electronic shift will not engage 4 wheel drive. the dash switch keeps on flashing and wont engage. it is same for both high and low. any info would be appreciated.
thanks mike

Check the 4x4 fuse to see if its blown. On the front axle on the passenger side is where the front axle actuator is located, just look for wires going to something screwed into the housing, it could be a metal or plastic actuator depending on whether it was updated. With the ignition on and a 4 wheel mode selected there should be power to the light blue wire(and brown wire will have power if you have the update). If the wires have power replace the actuator.

If you have the metal thermal actuator its easiest to just get another, to do the upgrade you need a wiring harness adapter and a spacer that goes into the axle

thank you will check it out. another question are parts i need only available at a chev dealer? thanks again.

thank you will check it out. another question are parts i need only available at a chev dealer? thanks again.


no Dorman makes the actuator part #600-101 you can get it at any auto parts store
it should look like this
https://www.dormanproducts.com/cgi-bin/vm91corp30r/item-dtl.w?sid=bmfDtjvvdjFbmahY011553013641461019&item=600-101&icrid=0x002a3630&clt=hwrap1&vsrch_str=&vsrch_brand=&vsrch_cat=&st_amount=&end_amount=&start=&vfrom=&prev=&vnext=&category_list=:0

With the switch lights flashing as you described I would suspect the encoder motor on the t-case.

With the switch lights flashing as you described I would suspect the encoder motor on the t-case.

I agree with that as well..the encoder transfercase motor engages 4WD....

the locking actuator motor only locks the front axles together...

hi
thanks for the replies. i have tried a few things and have something to add. with transmission in neutral and engine running - when i switch from 4-wheel high to 4-low there is a definite engagement in the axle. same sort of noise when back to 4-high. is this noise the actuator working. there are 2 electrical connectors attached to transaxle - when these are disconnected it still makes clunking noise when switchin between 4-high and 4-low. not sure if this photo i added is the encoder - it is threaded into side of transfer case and has a rubber sort of skirt on it.
thanks again for any help.
mike

hi
thanks for the replies. i have tried a few things and have something to add. with transmission in neutral and engine running - when i switch from 4-wheel high to 4-low there is a definite engagement in the axle. same sort of noise when back to 4-high. is this noise the actuator working. there are 2 electrical connectors attached to transaxle - when these are disconnected it still makes clunking noise when switchin between 4-high and 4-low. not sure if this photo i added is the encoder - it is threaded into side of transfer case and has a rubber sort of skirt on it.
thanks again for any help.
mike


the problem you have is either the encoder motor 90% or the transfercase...

your problem is no 4X4 drive correct ?

the encoder motor is binding or unable to move because of its lack of power to move..could be poor connections external and other possiblities..but not usually..


what is the fluid in it ? when/how often do you replace your transfercase fluid ,and what fluid do you use ?

the noise your hearing could be the transfer case engaging remove the avtuator from you front axle and let it hang their with your key on and i n withyour 4x4 on the actuator should come out if it dosent replace it this a very common problem for these

hi
yes the problem i am having is no 4 wheel drive. i use dexron lll oil and have changed it twice over 90,000 miles.
and i have removed actuator and tested it by toggling 4 hi switch and it did not move. would changing out actuator be the correct action to take?
thanks
mike

hi
yes the problem i am having is no 4 wheel drive. i use dexron lll oil and have changed it twice over 90,000 miles.
and i have removed actuator and tested it by toggling 4 hi switch and it did not move. would changing out actuator be the correct action to take?
thanks
mike


they no longer make dexron III...so you should check with the dealer with your vin to be sure of the correct fluid to use...

I believe it to be now on your 1997 tracII fluid...but check that with the dealer..the encoder is most likely binding or defective..some have found these parts for less than 200.00..

hi
yes the problem i am having is no 4 wheel drive. i use dexron lll oil and have changed it twice over 90,000 miles.
and i have removed actuator and tested it by toggling 4 hi switch and it did not move. would changing out actuator be the correct action to take?
thanks
mike

Check for power at the actuator connector(light blue wire) with 4hi and ign on. If there is power, replace actuator, if there is no power then the problem is elsewhere

Making a slow turn it a shopping plaza my truck shifted into 4 wheel drive by itself. Anyone ever heard of this. thanks dale

could be the switch on the dash.