Alright, so i go to up to one of our fields cause a buddy was going to go muddin in it...Ended up not being there so i went to pull into the field anyways to turn around. well i dont get to far before i need 4 wheel peel. Noo problem i think i got the duramax....heehehttp://www.dieselplace.com/forum/smileys/Approve.gif I push 4hi and it transfers in like a sec, i go to go ahead and i hear this horrid like grinding/clunkin noise, almost like it might be slippin on the shaft??....and i wasnt moving much(or at all) im like Holy sh!t wtf....go 4lo shifted like a peach i at least seemed could move but i dont think my front wheels were spinning I know my front drivers wasnt(i dont believe it ever did through the whole ordeal) and thats where all the noise seemed to come from to when it happened ....
Where i was, i shoulda walked right up and outta of it in 4hi no problem.Now that i think about it, i dont think my front ever locked in, cause like i said my drivers front never spun, and i dont see much in the way of mud on the other side...
I got all paranoid and when over to my buds house, whose father is the person who i bought my truck from and owns and runs the chevy dealer....Of course with it being on solid ground and not spinning the 4wd seemed fine and they said go ahead and run it, if it breaks thats waht warrantys for. Which is true, but id hated to break unneccassary if something is flubbed up.
Does any of this sound familiar to any problems any of you guys have had??? Nothing that i ever saw came up on the DIC screen, and the 4x4 lights never flashed...im at a lost. Maybes its paranoia, but i just know that something cant be right up front, this shoulda been a cake walk for the truck...
Also, when in 4lo i noticed that it toook a lot of brake pedal to get it to stop. And even w/pressing very firmly on the pedal the truck still was inching or wanting to move. And grinded going into park even when i was still...He(owner) mentioned that its something to do w/wire mesh still moving or something....,i dont know does that sound right to..???
Alright, give me the bad news...ill be back to read tonight sometime time for work....Thanks-Adam

The truck pretty much has to be moving for the 4wd to engage. If you had pushed 4hi when you rolling up the field you would have been fine. Also if you could move a little bit if you would have slowly and carefully moved a head while you were stuck without spinning right away it would have engaged as well. If you push 4wd when you're stuck and not moving then spin without it fully engaging, it will never engage and it will grind like you noticed.


Gm trucks have been this way since 88.

with the gear reduction in low range the brakes have a hard time holding the truck even at idle, you were probably still creeping when you put it in park

"wire mesh" http://www.dieselplace.com/forum/smileys/Confused.gif Maybe he was meaning "gear mesh"Edited by: mtomac

Mine does the same thing, I posted about it awhile back and no one seemed to know the answer. Put it in 4lo then come to a complete stop and put it in park--quickly--and you will here an awfull grinding noise. You can repeat it as many times (grinding) as you want by simply going from drive to park quickly. I just don't put it in park while in 4lo anymore.

The "trick" I have found is to coast/brake to a stop with tranny bumbed into neutral and DO NOT RELEASE BRAKE. Put tranny in park with brake still held, shift into 4 Lo and wait a few seconds and roll, easy for first few feet. To get out of low range, do the same. Works every time for me. Edited by: snoman

Whenever I shift to park, I pause at Neutral briefly then on to Park. Works for me.

Yep, you have got to get any preload off of the xfer case.

The truck pretty much has to be moving for the 4wd to engage. If you had pushed 4hi when you rolling up the field you would have been fine. Also if you could move a little bit if you would have slowly and carefully moved a head while you were stuck without spinning right away it would have engaged as well. If you push 4wd when you're stuck and not moving then spin without it fully engaging, it will never engage and it will grind like you noticed.


Gm trucks have been this way since 88.



Max- I think you hit it square on the head. That was what i was trying to get across in my jibberish. That it seemed like i hadnt engaged... So is it a nono, to shift into 4wd after im stuck in 2wd? Or that when i go to shift to 4wd i need to remember to be very careful getting back on the acclerator. Because last night i was unable to move at all(2hi),so i stopped hit 4hi, then proceed to go again. I cant remember exactly, but i kinda think i went back on the pedal...not hard or anything but prolly not as soft as i coulda...
I hear it click and i assume that i was engaged....
Well anyways, since its ablsoulty killing me all day at work, if it was engaged or not, me and my bud (same one mentioned before) head on up to mud hole to see whats gonna happen....I shift into 4 hi as i pulled into the field, and off i went....mud just a flinging from all 4 wheels...hehehe happy as could be...no grinding or clunking just smooth sailing...all the way across and almost back. Got w/in like 10 ft of the driveway and sunk in a hole...no biggie just gotta rock it a few times, and out she crawled...However...one time when i was rocking it in drive andmore or less just let off (from prolly like 2700-3000rpm) i heard it grind a little bit....??? not like yesterday but noticeable....http://www.dieselplace.com/forum/smileys/Confused.gif only did it that one time, i wonder if i didnt mess something up yesterday???twisted a joint or something..???


Would that have been enough to cause damage?? Its going to the paint shop in a month or so to get hood repainted(bubbling up,,, rust?) and then im gonna have it go next store to Chevy and have them do some stuff to it. Is it time consuming to have the 4wd inspected and checked out and whatnot? Or fairly simple for a trained tech??? Thanks guys for all the info and help...

I've never had a 'push button' 4x until this truck. I definately agree that it need to be engaged the right way to do it smoothly. I had a bit of what you describe when I first got the truck and used 4x the first couple of time.


Now, if I even think Im going to need 4LO I slow to a crawl, shift into neutral and with the truck still moving slowly, I hit the button. This way it goes into 4Lo very smoothly.


As far as 4HI, I just hit the button anytime as long as the truck is moving. I've hit the 4Hi button at over 40 mph in drive and it slides right in.


The truck definately does'nt like to engage 4x at a stop.

I have had better luck with it as a stand still as described above. The problem is even when tranny is in neutral it passes some torque and drives transfer case and when it is shift between hi and lo is gear spin from this torque. It is possible that if you do it at the correct slow speed which matched drive gears with driven gears speed that this may also be a reliable solution as well. Sitting still with tranny only in neutral is not that solution.

Is there a difference between the push button 4x4 and manual shifter? Cause we and old 88 or 89 2500 chevy that gets absoultly pounded, and when in mud we go as far as we can in 2wd, then when we can move, shift the lever to 4hi and take right off again no problem or anything....thats what i was thinking monday night, but didnt work out that way...http://www.dieselplace.com/forum/uploads/D56_000_03161.jpg

A couple of thngs to rember.


To go into 4 LOW the truck should be stopped in park. Put into neutral hit 4 LOW button. Put back into park. Then put into desired gear.


To go into 4 high just hit the button. Make sure the rear tires are not spinning. If they are spinning and you hit the 4high button you will put much strain on the drivetrain.


Maybe I have problems yet to come, but for know I have no grinding and I have no problem holding the truck back in 4low with normal brake pressure.


Sorry to here of your problems.

IF I have my tranny in neutral at a standstill it will never shift to low range without making a real noisy fuss. That way is a no go for me with my BorgWarner 4401 but it might work for you.

Hmm, interesting how different people and different trucks like to do their business http://www.dieselplace.com/forum/smileys/Embarrased.gif Although I haven't had any problems with the pushbuttons, I wish I had the positive shifter.





POLARBEAR, the difference is that the pushbutton system has electronics, vacume lines (?), solenoids, and ...????? to malfunction sooner or later.


The shifter is like shifting a manual transmission; Its gonna go

My 2 cents.

First, practice getting in and out of 2hi 4hi and 4lo when it doesn't count.

Second, shift between the ranges whenever you get a chance. It keeps things lubed in the cases and the front axle. I know people who go into 4wd once ayear andwonder why it is sluggish.

Last, 2hi <-> 4hi at any speed. If stopped, give the front axle a chance to engage before applying power. On a bad day, you might have to cycle the buttons a couple times till it catches. Wait for the front axle! You usually need some motion to get into 4lo. My truck requires you to be in neutral to get in/out of 4lo.

I have a manual shift. I have had a CLUNK when shifting from drive to park in 4lo. Maybe a mild grinding sound. Thought truck may still have been rolling slightly, but it happened again. I was concious of making sure truck was stopped.
The only thing I am really concious of is- drive line is free. Meaning no foot on brake, not in park. Drive line can turn, when shifting into 4lo, 4hi.
My Chev doesn't shift as well/smoothly as my old Dodge Dakota.

4 hi to 2 hi I have no problems at any speed and it seems to enguage faster when its rolling. I do take my foot off the trottle and let it do its thing before i hit the go pedal again. If I'm at a light and I am stoped I will let it enguage and then roll forward a few feet before I get on her just to make shure its enguaged.


Like fingers said, try to go into 4x4 once a month. Its best to try to do it on dirt or on gravel but worse case a heavy rainy day in town will work. But gravel is the best.


4 low I go at a slow roll(5 or under) put it in N and push the button for 4 low, wiat for it to enguage and then put it back in gear.

Wow, thanks for all the replys guys....Like in my earlier post after last night, w/my 4wheel peel working great, that on monday i mustve never been locked in. I prolly should have tried to back up a little shift 4 hi, then go slowly ahead til i was sure i had er in, instead of just shifting then trying to go ahead again....
I think (unless its overly time consuming) when it goes in in early sept, im gonna have them look it(4wd) over and make sure everything is aok...
Thanks again for all the help guyshttp://www.dieselplace.com/forum/smileys/Clap.gif