97 Z71 4wd Shift Problem

uniquebrett · November 24, 2008

I had some toruble recently when trying to use my 4wd...I managed to get into 4hi but it took several tries and some persistence. I have a push button shifter that normally has no problems, but last weekend I had to shift from 2wd to 4 hi and it would not engage, the light by 4 hi just kept flashing...signaling that I was still in 2wd. I just kept trying and eventually after puftting it in N and backing up. and then in Nuetral it fianally engaged to 4hi....after I was needing it bavk in 2wd...it took a long time to engage back to 2wd. It was fairly cold out that day...about 35F. Could that have been the problem or is this a signal something is going bad or about to break??? My truck has 162,xxx miles in it and is on its 2nd 4l60e. I need some asnwers so next time I need my front end I am not stuck....Help appreciated...thank you

Brett

peteking · November 24, 2008

My mom had an identical issue with her 1998 Blazer. There's an electronics module that controls the operation of the transfer case. That's what malfunctioned in her case. Cost about $250 bucks to replace, and it was fine after that. At least I'm pretty sure that's what happened. Other members can correct me if I'm talking out of my @$$.

Good Luck!

Mike G · November 24, 2008

I had a similar problem on my 96 S10 blazer. There was a vacuum type modulator located under the battery tray that fixed the problem. I am not too familiar with the Full size truck system however, but it's something to look into other than the transfer case encoder motor (as mentioned by Peter). My 92 still has the lever on the floor...

--Mike

alwcurlz · November 24, 2008

I had some toruble recently when trying to use my 4wd...I managed to get into 4hi but it took several tries and some persistence. I have a push button shifter that normally has no problems, but last weekend I had to shift from 2wd to 4 hi and it would not engage, the light by 4 hi just kept flashing...signaling that I was still in 2wd. I just kept trying and eventually after puftting it in N and backing up. and then in Nuetral it fianally engaged to 4hi....after I was needing it bavk in 2wd...it took a long time to engage back to 2wd. It was fairly cold out that day...about 35F. Could that have been the problem or is this a signal something is going bad or about to break??? My truck has 162,xxx miles in it and is on its 2nd 4l60e. I need some asnwers so next time I need my front end I am not stuck....Help appreciated...thank you
Brett

I would check the vacuum line that goes to it if it has one. I can't remember if it does on those full-size trucks.

uniquebrett · January 2, 2009

I had some toruble recently when trying to use my 4wd...I managed to get into 4hi but it took several tries and some persistence. I have a push button shifter that normally has no problems, but last weekend I had to shift from 2wd to 4 hi and it would not engage, the light by 4 hi just kept flashing...signaling that I was still in 2wd. I just kept trying and eventually after puftting it in N and backing up. and then in Nuetral it fianally engaged to 4hi....after I was needing it bavk in 2wd...it took a long time to engage back to 2wd. It was fairly cold out that day...about 35F. Could that have been the problem or is this a signal something is going bad or about to break??? My truck has 162,xxx miles in it and is on its 2nd 4l60e. I need some asnwers so next time I need my front end I am not stuck....Help appreciated...thank you
Brett

I would check the vacuum line that goes to it if it has one. I can't remember if it does on those full-size trucks.

I am unable to locate a vaccuum line any where near the battery.....horn is just below and in front of the battery. I would venture to guess that my 4wd system is different than yours. I still have the same problem of not being able to engage my 4wd.....any fixes -or suggestions????

zaac · January 3, 2009

Sounds like it's the encoder on the TC. Can you here the electric motor trying to shift?

uniquebrett · January 3, 2009

Sounds like it's the encoder on the TC. Can you here the electric motor trying to shift?

I tried 5 times while idling in park and all I heard was a quiet clicking up under the dash ( near the light switch)....then I tried while idling in Nuetral and I heard the same clicking, but 2 out 5-10 tries....I heard a loud clunk under the truck as if it was trying to engage, but the 4 hi light on the button kept flashing....so it was not fully engaged....the light is on constantly when it is in 4hi or 4 lo....different lights on the buttons....so I still have the problem, the clunk does not happen every time I try to shift....just sometimes.

Brett

zaac · January 4, 2009

Sounds like it's the encoder on the TC. Can you here the electric motor trying to shift?

I tried 5 times while idling in park and all I heard was a quiet clicking up under the dash ( near the light switch)....then I tried while idling in Nuetral and I heard the same clicking, but 2 out 5-10 tries....I heard a loud clunk under the truck as if it was trying to engage, but the 4 hi light on the button kept flashing....so it was not fully engaged....the light is on constantly when it is in 4hi or 4 lo....different lights on the buttons....so I still have the problem, the clunk does not happen every time I try to shift....just sometimes.

Brett

OK, forget what I said, lol, I don't think it's the encoder anymore. I just replaced my encoder cause after I put it in 4wd I couldn't get it out but I could hear the motor groaning away trying to shift. The previous owner had already replaced the buttons because the lights were doing weird things including, I think, 2 lights staying on at the same time and 4wd not working properly. I'm starting to think you might have the same problem. I think the buttons might be a bit cheaper than the encoder if that makes you feel any better. I hate this push button electric stuff.

uniquebrett · January 4, 2009

Sounds like it's the encoder on the TC. Can you here the electric motor trying to shift?

I tried 5 times while idling in park and all I heard was a quiet clicking up under the dash ( near the light switch)....then I tried while idling in Nuetral and I heard the same clicking, but 2 out 5-10 tries....I heard a loud clunk under the truck as if it was trying to engage, but the 4 hi light on the button kept flashing....so it was not fully engaged....the light is on constantly when it is in 4hi or 4 lo....different lights on the buttons....so I still have the problem, the clunk does not happen every time I try to shift....just sometimes.

Brett

OK, forget what I said, lol, I don't think it's the encoder anymore. I just replaced my encoder cause after I put it in 4wd I couldn't get it out but I could hear the motor groaning away trying to shift. The previous owner had already replaced the buttons because the lights were doing weird things including, I think, 2 lights staying on at the same time and 4wd not working properly. I'm starting to think you might have the same problem. I think the buttons might be a bit cheaper than the encoder if that makes you feel any better. I hate this push button electric stuff.

So does anyone know of a test that I can do to start fixing the present situatuion? I do not want to go to the dealer and pay them to do it....I need to save as many$ as possible. I can remove my dash panel and look at the connections, but it seems that they are alright...I know I am getting currnet to each light/button anyways.....still searching for advice.