Well, after getting the suburban running top notch....with new plugs and wires...No codes thrown, no mis fires etc....that part has been worked out so it seems. I get up this morning to plow my driveway since we are in the middle of the biggest strorm of the season.....FREAKIN 4wd front axle accuator dies. I'm dead in the water...snow starts fast and furious, and now I am behind the 8 ball. got my mechanic to get me a tow out and up to his place and new actuator in....Too much sloppy wet snow at this point and Can't move it. Burb shifts good now though. Hopfully this is the last of it now.
One thing after another....suburban tales!
- Thread starter kojackJKU
- Start date
FeralBoy
Observer
I seen this before the 4 wheel drive is actuated by a vacuum switch and if it freezes it doesn't work right check that first
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Watt maker
Active member
These actuators have always been an issue. Did yours have the thermo unit or the newer electric unit? I'm assuming that you replaced it with a new electric actuator but if you want something a little more reliable, I recommend these: http://4x4posi-lok.com/app_chevy-k.html
Well...after 8 plus hrs of trying to clean up snow, dig out the cars, etc. I got in the suburban to "try" the 4wd switching. I am very surprised at how fast it changed from 2wd, auto and 4wd high. its damn near instant now...and no fighting with the switches. impressed to say the least. HOPFULLY that is the last of the crap going wrong with this for awhile now. I want to enjoy the rig, not fix it or worry about it.
Changing the plugs and wires DID fix it. I cleared the codes, after I replaced the plugs and wires, a week ago, and Never got one. I am guessing that the computer can't distinguish between whats causing the misfire. OR, there was not good contact between the coils and wires causing a false reading. Either way it idles, drives, and has power like it should. FINALLY. I am expecting the MAF code to come back, but it hasn't yet.
Bane Harper
Observer
A sigh of relief.....plugs and wires it is
Good Luck Kojack
Good Luck Kojack
Martinjmpr
Wiffleball Batter
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So, out of curiosity and for the edumication of us other GMT800 owners, what is the symptom of this?
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I know that when you push the button on the dash, two separate things have to happen: The transfer case itself has to shift into 4wd through the 4wd actuator on the T-case, AND the front axle has to be engaged. So if the T-case engages and the front axle does not, what happens? Does the 4wd light flash or is there some error message that pops up on the DIC?
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And while I'm at it, another dumb question: would it be possible to swap in the front axle assembly from an AWD Denali or Escalade that presumably deletes this feature? I realize it might accelerate wear on the CV joints and might increase drag and decrease MPG, but would it be worth it to eliminate this point of failure? Or are there other factors I'm not considering like how it would affect the on board computer, etc?
Martinjmpr
Wiffleball Batter
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According to the web site that appears to only be applicable to GMT-400 trucks (1998 and earlier) not GMT-800 (2000 - up.)
Martinjmpr
Wiffleball Batter
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OK, Disregard, I guess I had assumed that the Chevy's of this era had the sometimes problematic vacuum-powered front axle disconnect (I think my '99 4runner did and I think the wife's 1995 Jeep YJ Wrangler does, too.) I know those were prone to failure since the hoses would dry out, become inflexible, get cracks, etc.
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Just did a little research and apparently the front axle actuator on the GMT-800 trucks is electric and fairly easy to replace. So doing a swap-in of a full time 4wd front end would not only cause more wear to the front end, but it would be like using a sledgehammer to swat a fly - Complete overkill.
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Having said all that - I'm grateful for the link to the Posi-Loc. I think I may put that on the wife's YJ. It's basically an off-road toy so most likely we wouldn't get the switched one, we would just do the permanent front axle connect and not have to worry about it.