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When I put my truck in 4 hi it makes a clunking noise when I touch the accelerator. I was wondering if anyone else has had this problem. Was it the Transfer case chain slipping or the front differential not engaging.
 

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I haven't had that problem.

Have you checked for the dreaded transfer case leak?
What's the oil level in your T/case? Checked it yet?
Maybe yours started leaking and you lost the fluid and (hopefully not) fried your T/case.
 

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Jaymes Maciejewski;1573677; said:
When I put my truck in 4 hi it makes a clunking noise when I touch the accelerator. I was wondering if anyone else has had this problem. Was it the Transfer case chain slipping or the front differential not engaging.

Mines been doing the same thing, I have yet to find an answer. I'll let you know if I do.

-Dustin-
 

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Mine is doing that. Feels like it is jumping a tooth in the transfer case. Does it in lo and high. The steering wheel will jerk to the right when it does it. It is intermittent and usually does it once every 15 seconds or so. I am taking it in tomorrow.
 

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I always make sure my truck is moving a bit (not under acceleration)before I put it in 4HI and I make sure that I use 4wd at least once a month even if it's just up the driveway (30 yards). So far no noise, but that's not neccessarily because of my routine....may just be lucky.
JP
 

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It's probably just the front diff. engaging.
 

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this happened to me in the snow and was remedied by pulling my in cab manual actuator(Posi-Lok). apparently the actuator pin wasn't quite in far enough-a half inch pull stopped the clunking. i do not like hearing my truck make those noises. i'm still trying to figure out why GM continues to use these types of actuators(mech/electrical thermal linear or vaccum). good luck
 

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dhg;1591881; said:
i'm still trying to figure out why GM continues to use these types of actuators(mech/electrical thermal linear or vaccum). good luck
I've been the steady maintenance guy on our GM fleet since '95. Never an actuator failure. Had the harness melt on a non-fleet '95. All of them are on their way to my invisible 200k mile mark for fleet service removal or they've already been past 200k and sold.

Again, never an actuator on the front axle. Weirdest I ever got was I changed the pass side front axle seal just like I do the driver's side and the flat thrust washer between the axle stub and the diff stub slid out of position. Duh, you have to pull the pass side housing off to change that seal. It made some grinding noise at first then the washer fell away all together = no noise and no 4wd.
 

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bcserl;1591205; said:
Mine is doing that. Feels like it is jumping a tooth in the transfer case. Does it in lo and high. The steering wheel will jerk to the right when it does it. It is intermittent and usually does it once every 15 seconds or so. I am taking it in tomorrow.
Any progress on this. Mine does the EXACT same thing. I'll be fixing it when I get both time and money.

-Dustin-
 

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It turned out to be the eletric motor/actuator that extends and retracts to put the front axle into four wheel drive was acting up. Dealer never found it, blamed my arb air locker. Drivetrain Direct in Corona, CA the ones that did my arb air locker figured it out and fixed it for free.
 

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bcserl;1748537; said:
It turned out to be the eletric motor/actuator that extends and retracts to put the front axle into four wheel drive was acting up. Dealer never found it, blamed my arb air locker. Drivetrain Direct in Corona, CA the ones that did my arb air locker figured it out and fixed it for free.
Man! Talk about good service! I would definitely be spreadin' the word in your area about those guys. One good turn deserves another.
JP
 

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The amazing thing is he took apart the whole front end just to make sure it wasn't an assembly problem or a broken part on his end since the ARB locker was still under warranty. Then he figured out it was the actuator, found a used one in his shop and put it on. Problem solved. Unbelievable service...all for free on his dime.
 

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Then I guess I can confirm what I thought it was from the very start. Your talking the actuator, as in the one for the transfer case right? Did you have the whole motor changed? Thanks, just trying to track donw exactly what mine is doing.

-Dustin-​
 

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I think the actuator he is talking about is the one on the front axle. Because mine is a manual shift and does the exact same thing. If this is correct how do you remove the actuator to replace it. Also does anyone know if there is a way to test the one in there.

Thanks
 

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01Phd;1754789; said:
I think the actuator he is talking about is the one on the front axle. Because mine is a manual shift and does the exact same thing. If this is correct how do you remove the actuator to replace it. Also does anyone know if there is a way to test the one in there.

Thanks
Unplug it, spin it out and plug it in and let it hang. Cycle 4wd now. It should extend in 4x4 and retract in 2wd. Also, with it out, depress the plunger in the hole where the actuator was and it should depress, engaging the 4wd. You may have to spin one tire slightly to allow engagement.:D
 

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When I hit the button to engage 4wd, there is one hellava bang. I dont even know if its engaging. Its darn scary. There isnt any noise when going back into 2wd.

This truck is a member of the pump rub club.
It sounds like the bang is coming from the transfer case. The transfer case hopefully should be fixed this week.

Will this problem also be fixed when the transfer case pump rub thing is fixed or is this another thing?
 

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I replaced the actuator and it seemed to help but it still does it. It seems to me like it is still not engaging or it is slipping. I am going to take the tube that extends to the half shaft when I replace them next month and see what is broke. My truck is also a member of the pump rub but I don't think that the transfer case is making the noise(hope not!) Has anyone had the front axle apart to see how the front diff engages and what could be the problem?

Thanks,
Josh
 

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Drivetrain Direct took off the rear drive shaft and drove it with just the front wheels. That's how they proved their theory that the actuator was engage/disengaging.
 

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Well I took off the rear driveshaft and the pop intensified greatly. It feels like it is slipping or the cv joint is binding heavily. Also the noise sounded like it was coming from the transfer case at times. I guess i will disconnect the front driveshaft and put it in 4wd to see if the noise is comin from the front axle when i turn or put it under a load. I know I have a lot of metal flakes in the transfer case oil. Not really sure what I should do. Any Ideas?
 

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Not sure either but I have also found a metal flake color to my transfer case fluid the last time I changed it, I'll be doing it again tomorrow, I'll also try to check the front diff actuator.

-Dustin-
 
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