4wd Problems on 05 Sierra

kevenn · January 27, 2005

I have a new 2005 GMC Sierra Crew Z71 with AutoTrac and only 1000 miles. The other day I got stuck, so I put into 4-HI and waited until the light quit blinking to make sure it was engaged. When I gave it some gas the rear-end was spinning, and the front-end made this clicking sound (the front wheels were not spinning), then I felt it finnaly grab and I walked right out. So I decided to test the truck out. Now if I'm driving 10-20 MPH and I put into 4-HI it goes in smooth EVERYTIME. It's only if I'm completely STOPPED and I put into 4-HI do I get this clicking sound and it's not everytime. I'd say I get the clicking sound 1 out of every 6 times I engage 4HI, only from a stopped position. Like I said it goes in smooth everytime while I'm driving. Is this a problem? What is the clicking sound (gears grinding?) and am I damaging my vehicle when I do this. The manual says you can put it into 4-HI at any speed. My dealer says it's normal, but my buddy has a 2004 Z71 and he said it's never happened to him.

Please help! I'm pulling my hair out here...thanks!!

budhayes3 · January 27, 2005

My 99 doesn't make any noise, but it seems to be somewhat common among the newer models...I remember a few posts from biochemist with the same concern. Here's one of them:

http://www.gm-trucks.com/forums/index.php?showtopic=37747

tryn2lrn · January 27, 2005

I have a new 2005 GMC Sierra Crew Z71 with AutoTrac and only 1000 miles. The other day I got stuck, so I put into 4-HI and waited until the light quit blinking to make sure it was engaged. When I gave it some gas the rear-end was spinning, and the front-end made this clicking sound (the front wheels were not spinning), then I felt it finnaly grab and I walked right out. So I decided to test the truck out. Now if I'm driving 10-20 MPH and I put into 4-HI it goes in smooth EVERYTIME. It's only if I'm completely STOPPED and I put into 4-HI do I get this clicking sound and it's not everytime. I'd say I get the clicking sound 1 out of every 6 times I engage 4HI, only from a stopped position. Like I said it goes in smooth everytime while I'm driving. Is this a problem? What is the clicking sound (gears grinding?) and am I damaging my vehicle when I do this. The manual says you can put it into 4-HI at any speed. My dealer says it's normal, but my buddy has a 2004 Z71 and he said it's never happened to him.

Please help! I'm pulling my hair out here...thanks!!

<{POST_SNAPBACK}>

I don't have the autotrac but my manual says something like a little light forward acceleration will aid in the smooth engagement of 4HI. If you are not moving the gears might line up so the teeth can not mesh together easily and get hung up (even though I believe there might be some kind synchros in there, the pros will know). If you are moving it will allow the teeth to pop together easier. As an example the book also states for 4LO you need to be moving in neutral at 2-3mph since I believe LO has no synchros. I believethe clicking you hear is the gears trying to engage but spinning until they finally mesh together. This is my belief and I may be wrong, if I am I apologize and the experts here will be able to explain it better.

99silveradoz71 · January 27, 2005

There have been about 2 other current posts on this either here or in the HD section. You may want to look there for more info.

biochemist · January 27, 2005

hello kevenn...read my posts from the last couple of weeks. My truck has done the same thing....but less frequently ~1-60-80 times....or rarely if you will...look for my earlier cliking or engagment issues posts...you will find them a few pages back and also today. I have discussed this with many dealers locally and it is deemed normal as your dealer says... where are you? I even called to my birth-state and got the same message from a number of dealers there. One said they hear this when they move the trucks for snow removal...and if a manual shifter is invovled they may have to move the truck forward or backwards a foot or two before they can shift it in 4Hi....Another stated a new Colorado was in for the same noise...nothing found. I am with you, nervous about what that noise is/was.....apparently the dealers will tell you if sitting still they expect to hear this occasinally....they state this is a shift-on-the-fly system and that it will engage while sitting, but it is best to be moving forward...makes sense if you think about it...I have heard the exact same thing (sort of a faint low pitched click for a couple seconds until it locks in and off you go..sounds like your finger trying to slow a rotating bike tire.. or a ratchet sound perhaps...some dealers call it gear 'hunting'...not sure exactly what is going on but a number of dealers actually told me not to bother letting them look at it how is that for honesty, turning down warranty work!!! They say it is just that the components were not aligned properly since nothing was moving and they have to mesh...then you get the noise...Beleive me, I have called a number of dealers and asked to speak to the service manager/foreman many times...all said no problem, have heard it, never hurts anything...even visited a couple..same response...read my post from today...they even say you can push the button with you rears spinning at 30-40 mph....will get a loud noise/bang but it will not hurt anything....although I am not planning on testing that. as far as your 1 out of 6 number it may be just htat your truck is very very new adn the transfer case is adjusting...may become less frequent when it has more miles on it...Get back with me and let me know what you think, I hope this helps and please read my post from today, I think you can leave you hair alone...later

biochemist · January 27, 2005

I guess it should be pointed out (unless I am wrong) that autotrac transfer cases are SOTHF...and that the manual jobs are also, but I think they work differently....(I think they are different model transfer cases). Guys have said thier new trucks grind loudly if you are not forceful in shifing the lever...I read today where guys have to be very forceful or sometimes moving (as I said earlier) to engage...so I would expect autotrac systems to work a bit differently and again, probaby better when moving slightly...that is why we do not hear it when we are moving. I guess we cannot be as forceful when shifing, that is the encoder motors job...but stuff has tobe aligned properly...and occasionally it is not...so the same thing happens to pushbutton systems as well....I am rambling...but I hope this helps...if anyone is an expert please help us understand. Thanks and hope I am clear enough,

biochemist · January 27, 2005

Any comments Kevenn.....

kevenn · January 28, 2005

Thanks for the reply's, but is there any technicians out there?

I was just wondering if the clicking noise is a safety mechanism so that nothing major happens, or is it actual gears grinding?!? I just want to make sure I didn't damage the truck. Also it doesn't seem to be many posts on this problem, maybe some people just haven't spoken up yet.

thanks again!

lrymal · January 28, 2005

Also it doesn't seem to be many posts on this problem, maybe some people just haven't spoken up yet.

thanks again!

<{POST_SNAPBACK}>

Mine is quiet... but - but. Take your truck to the dealer, express concern, have them write it up on a trouble ticket. IF (IF!) there is a problem, it is a warranty issue, and it is ALWAYS a good idea to have a concern like this in the customer database.

I **never** hestitate with my dealer about potential warranty issues. And if the behavior is normal, have the dealer give you some one-on-one training. Indeed, the sales droid should have done this anyway.

biochemist · January 28, 2005

Thanks for the reply's, but is there any technicians out there?

I was just wondering if the clicking noise is a safety mechanism so that nothing major happens, or is it actual gears grinding?!? I just want to make sure I didn't damage the truck. Also it doesn't seem to be many posts on this problem, maybe some people just haven't spoken up yet.

thanks again!

<{POST_SNAPBACK}>

Kevenn, a tech would be nice I agree, as I stated I have spoken to numerous techs and service managers...all state normal (and I do mean alot..I am anal about this type of stuff)..however mine only does this rarley..not 1 of 6 as you state. lrymal is right, if it makes you feel better take it to the dealer and tell them...maybe at your next service appt or oil change. Chevy pays for them to fix warrantied vehicles (this is actually how dealers make a very large percentage of their profit...not on new sales...as some folks like to think, so if they thought it was not functioning properly they would definatley. have you come in), if they think it is normal it may just be...I am/was skeptical also, but every person I speak with says the same thing....it is the transfer case gears meshing or possibly the motor in the front diff engaging but has yet to do so because your are sitting still....I think it is as simple as that...I mean you never hear it when moving, right? Probably the gears finding each other and locking in. I have spoken with service managers that have been with chevy for 30 years and they have really seen it all. I am not defending the "it is normal" statement, but my guess is that if multiple dealerships say so, and no lights are on, and it works well, then well, maybe it is normal for it to do this once in a while while engaged sitting still. The explaination makes sense...but if you find out anything else let us know for sure...

kevenn · January 28, 2005

Thanks for the insight Biochemist! One thing I'd like to make clear is when I'm at a complete stop and I shift into 4HI when I'm NOT STUCK it goes in smooth everytime. It's only when I'm stuck and the front wheels can't spin does the "clicking" happen and even then it's maybe 1 in 6 times, but I seen an earlier post that moving the steering wheel back and forth after engaging but BEFORE giving it gas might help the engaging process...any thoughts?

biochemist · January 28, 2005

Thanks for the insight Biochemist! One thing I'd like to make clear is when I'm at a complete stop and I shift into 4HI when I'm NOT STUCK it goes in smooth everytime. It's only when I'm stuck and the front wheels can't spin does the "clicking" happen and even then it's maybe 1 in 6 times, but I seen an earlier post that moving the steering wheel back and forth after engaging but BEFORE giving it gas might help the engaging process...any thoughts?

<{POST_SNAPBACK}>

I guess that is when mine does it also, just when I need the fronts to spin. I found an icy hill this morning and stopped on it, pushed the button and it locked right in with no noises and went...so, as I stated, mine does this rarley. But, the wheel back and fort is a good thing but the main thing I have been told is it is good to be moving, even just a little. The transfer case will make that noise until the gears and components mesh and then you are off...right? I read where your makes the noise then locks in and off you go...is this right? Also depends on how much gas you give it I would assume...if the components are about aligned and you give a bit too much for them to catch, well you know, but if you ease into it, maybe that helps...not sure. My guys say reproducability is your key, if something is truley wrong then you will KNOW, lights, bad sounds, won't work at all. They also say they have very very few issues with these transfer cases, very tough . Also some on this forum say if you hear nothing then you should worry , so at least you hear something if that makes you feel a bit better...but it sounds as if your truck does not do this all the time...Sounds like what I have experienced and what the dealers say they see when moving the lot for snow removal. I assume what you describe happens in a matter of a couple of seconds? Anyway, has your dealer said anything else about this? Mine has assured me this is normal and nothing is being damaged and what I describe is what they would expect to hear when engagin at a stop occasionally...as I said before, they make $$$$ on warranty work from Chevy...the would want to fix it if it was not working right for you. Let me know,

kevenn · January 28, 2005

Hey Biochemist, some good news! I'm really good friends with the salesman at the GMC dealership where I got my truck...and I asked him today (during my lunch break) if I could take a brand new Sierra for a test drive. I told him that if I could reproduce the sound, then I'd feel better, and it would support the theory that they ALL MAKE THE CLICKING SOUND. So I Drove off to a favorite spot of mine, with lots of snow...and guess what? I was able to reproduce the sound 5 times...I must have put it in 4HI 30-40 times!! I tried stopping, going up hills, giving it lots of gas, and not giving it gas at all, I tried everything. I came to a conclusion, it only makes the clicking sound when your back wheels are spinning faster than your front wheels while you put it into 4HI, and even then it's not all the time...I talked to their Master Mechanic, and he also told me that the sounds are normal, and that no damage is being done to the axel or transfer case.

Either way I was able to test it out on a new truck, other than my own (I baby mine), to get a really good feel about what is really going on...now I can relax, and continue enjoying MY new truck Thanks for everybody's help!!

biochemist · January 29, 2005

Hey Biochemist, some good news! I'm really good friends with the salesman at the GMC dealership where I got my truck...and I asked him today (during my lunch break) if I could take a brand new Sierra for a test drive. I told him that if I could reproduce the sound, then I'd feel better, and it would support the theory that they ALL MAKE THE CLICKING SOUND. So I Drove off to a favorite spot of mine, with lots of snow...and guess what? I was able to reproduce the sound 5 times...I must have put it in 4HI 30-40 times!! I tried stopping, going up hills, giving it lots of gas, and not giving it gas at all, I tried everything. I came to a conclusion, it only makes the clicking sound when your back wheels are spinning faster than your front wheels while you put it into 4HI, and even then it's not all the time...I talked to their Master Mechanic, and he also told me that the sounds are normal, and that no damage is being done to the axel or transfer case.

Either way I was able to test it out on a new truck, other than my own (I baby mine), to get a really good feel about what is really going on...now I can relax, and continue enjoying MY new truck Thanks for everybody's help!!

<{POST_SNAPBACK}>

Very good kevenn....told you, just kidding. One question though, I read in your orignal post you said you were always STOPPED, then engage, then you heard the clicking when your rears started to spin while your fronts where stationary (While STUCK...if you can move forward you do not hear this noise) until it clicked in and the you were fine....but in your testing of the new truck you say when the rears are spinning faster than the fronts is when you hear this....Did the new truck you tested click when you engaged at a stop in the snow when stuck? It is a bit unclear for me....(I assumed the clicking is when your rears are spinning faster than the fronts when the button is pushed and the components are not lined up just so)...but I read that your truck does this when completely stopped and STUCK...did the new truck exhibit this also...clicking at a complet stop while stuck? In other words you are NOT saying if you are on ice and your wheels are spinning THEN you push the button, that this is the only time you hear this...you would also hear a clunk too.. if so this is a different scenario...You are happy so I assume the new truck did the same as yours or you would not be so...? I would like to know, but it is very nice to have reconfirmation on the subject from someone you trust and who is a master mechanic. I am proably not reading your post right, been a long day...but do let me know, Basically, did the new rig exhibit the behavior in your original post??? thanks

biochemist · January 29, 2005

Sorry for the long winded posts...just want to clear it up as you do. Did the mechanic give any advice on how to limit these noises..slowly driving then engage, or something else or just say no problem...go enjoy your truck?! You are not the only one on this forum who is anal about thier trucks...that is why we are here...Thanks again and glad you/we all learned something...is this your first 4x4?,