Please login or register.

Login with username, password and session length
Advanced search  

News:

Keep CAFCNA Alive! Become a Supporting Member Today!

Pages: [1]   Go Down

Author Topic: Dropping out of gear in 2WD  (Read 12216 times)

0 Members and 1 Guest are viewing this topic.

snmhanson

  • Full Member
  • ***
  • Offline Offline
  • Posts: 30
  • I love the Chevy Avalanche!
Dropping out of gear in 2WD
« on: 12/08/09 10:23 AM »

Been a while since posting here but I have received excellent advice in the past.  I have a 2005 Avalanche which has been a great truck once I got beyond some initial issues that were covered under warranty.  Over the past couple days I have been dropping out of gear fairly consistently while driving in 2WD.  I can usually start off driving in 2WD and drive for a while but then all of a sudden I will lose my gearing - like I just shifted into neutral or something.   It has happened once from the start as well where I started my car, shifted into drive but the engine just reved.  In general the only way to get moving again is to shift into AWD and drive it that way for a while.  Turning off the car, shifting into park, etc...   doesn't seem to solve the problem.  Now I am just leaving the car in AWD so that I don't lose my gearing in a critical spot - such as when I'm turning in front of a approaching car.  We just got our first blast of cold weather so my first instinct is that the transmission fluid is low.  However, I don't understand how I would be able to drive in AWD fine and just not in 2WD if that was that case.  I am due to get my transmission fluid serviced and I need an oil change so I made an appointment on Wednesday morning.  Nevertheless, I am still curious as to what may be causing my problems.  Any ideas?

Thanks,

Matt
Logged
05' 1500 LT, WBH, Dark Blue Metallic, 4.10 axle ratio, Mods to come.

Troublemaker

  • CAFCNA Cruise Coordinator
  • Full Member
  • *
  • Offline Offline
  • Posts: 4,776
  • NY NY DC PA
Re: Dropping out of gear in 2WD
« Reply #1 on: 12/08/09 11:04 AM »

check for leaks on the rear differential.  My 05 has a small leak there, need to replace the pinion seal, and refill the diff with gear oil.
Logged
Click the pic to listen along!

wrenchdaddy

  • Full Member
  • ***
  • Offline Offline
  • Posts: 46
  • I love the Chevy Avalanche
Re: Dropping out of gear in 2WD
« Reply #2 on: 12/08/09 11:50 AM »

If your transmission isn't slipping when it IS actually in gear and driving, it sounds like something with the 4wd system. Maybe 4wd gear selector actuator? Has it ever jumped out of gear when you have it in 4wd?
Logged

snmhanson

  • Full Member
  • ***
  • Offline Offline
  • Posts: 30
  • I love the Chevy Avalanche!
Re: Dropping out of gear in 2WD
« Reply #3 on: 12/08/09 03:11 PM »

Thanks for the advice Troublemaker.  I actually went and had my oil and transmission fluid changed today and had them check all other fluids in the process.  None of the other fluids including the rear diff and transfer case were low.

In response to your question wrenchdaddy, I don't recall it ever jumping out of gear while in AWD.  As far as I can tell it drives pretty much fine when it's in AWD.  I hope it's ok to drive in AWD (FWD in this case) until I get it into the shop.  I am not sure if the front drive system is designed to be able to handle the stress of propelling the truck without the rear drive assisting it.

Also, I don't think the transmission is slipping at all while driving in 2WD.  The drivetrain seems to be either fully engaged or fully unengaged but nowhere in the middle.  Since I seem to be able to drive fine in AWD I have kind of ruled out a transmission problem and I figure it must be in the transfer case, rear diff, 4WD system or electrical system.  Does that make sense or could it in fact be a transmission problem?

Thanks again for the insight.  Hopefully this won't be a major fix.

Matt
Logged
05' 1500 LT, WBH, Dark Blue Metallic, 4.10 axle ratio, Mods to come.

wrenchdaddy

  • Full Member
  • ***
  • Offline Offline
  • Posts: 46
  • I love the Chevy Avalanche
Re: Dropping out of gear in 2WD
« Reply #4 on: 12/08/09 03:52 PM »

Matt, Def sounds like a transfer case problem. You can rule out the differentials, if somethin was broke in there you couldn't go anywhere no matter what gear you were in. When you are in awd I would bet your rear wheels are also engaged, its nearly impossible for the front to be engaged by itself, so no, you're not hurting anything driving it like that. It comes down to the actuator in the transfer case. Its a small motor that engages the gears in the transfer case depending on what button you push. Does it ever make any noise when it drops out of gear by itself? grinding? whining? clunking? The actuator may not be engaging all the way in 2wd or kicking it into neutral for some reason. Does your "service 4wd" light come on?
Logged

snmhanson

  • Full Member
  • ***
  • Offline Offline
  • Posts: 30
  • I love the Chevy Avalanche!
Re: Dropping out of gear in 2WD
« Reply #5 on: 12/08/09 04:30 PM »

I have not gotten the service 4WD light yet.  I don't hear any noise at all when it drops out of gear.  Here are a few examples of what's happening:  1) This morning I was driving along and started coasting downhill.  The road flattened out so I accelerated a bit and instead of power to the wheels I only got increased rpms.  I had no idea that it had dropped out of gear until applying the gas.  2) Earlier today when I started it up and tried to back up it was out of gear and would not move.  When I shifted into AWD (didn't put it in park - left it in drive) it did make a grinding noise for a few seconds as the AWD engaged.  3) I was testing it in a parking lot after my transmission fluid change.  I was driving along pretty slowly and took my foot off the gas.  When I put my foot down on the gas pedal I got nothing.  I stopped and when I shifted back into park I heard a small amount of grinding.  In all these cases putting the rig in AWD made it perfectly driveable.

I should also add that a couple months ago I was driving kind of eratically in reverse up a driveway.  I turned around a corner in the drive and then applied the brakes to stop.  As I came to a stop there was a pretty major lurch.  I thought that I had hit something so I put her in park to get out and check it out but left the engine running.  Well, after I jumped out my truck started rolling forward and I almost lost it into a ditch before I was able to jump back in and put the brakes on.  I don't remember for sure if I only had to turn it off and on to get it back into gear at that time or if I had to shift into 4WD.  I do know I did shift into 4WD though because the front of my truck was in the ditch and I wanted to make sure I got out.  Like I said, that was a couple of months ago and until yesterday I didn't see any evidence of it acting up anymore.

I just finished reading some of the posts from the very long drivetrain problem thread and am a bit afraid that I am in for a pretty major repair.  I will keep my fingers crossed but I know my luck and it is not sounding too good at this point.  I have a sister-in-law who's family owns a Ford/Nissan dealership so I may be stopping in to see them soon if this ends up being too big a repair.  I like my Av but not enough to go down this road...

Thanks again for the help,

Matt
Logged
05' 1500 LT, WBH, Dark Blue Metallic, 4.10 axle ratio, Mods to come.

snmhanson

  • Full Member
  • ***
  • Offline Offline
  • Posts: 30
  • I love the Chevy Avalanche!
Re: Dropping out of gear in 2WD
« Reply #6 on: 12/14/09 07:00 PM »

A quick update for anyone who is interested:

Just picked my rig up from the shop.  It didn't get fixed but the mechanic knows what is wrong.  He said it is a common problem with Chevy's but he had to track down a couple of parts to fix it.  I forget what the actual problem is but basically I need a new selector switch and a new sensor.  He said it shouldn't be too expensive and that I would be fine driving in AWD until the parts come in.  So, good news.  My transmission, diff, etc...  seem to be fine.  Quite a relief because typically when I have a problem a car it ends up being a big and expensive deal.

Matt
Logged
05' 1500 LT, WBH, Dark Blue Metallic, 4.10 axle ratio, Mods to come.

deamion

  • New Member
  • *
  • Offline Offline
  • Posts: 1
Re: Dropping out of gear in 2WD
« Reply #7 on: 10/20/10 10:20 AM »

Hey snhmanson, What were the parts you ordered to fix this problem? My 2005 Chevy Avalanche is having the exact same problems you were having. Iam two driving in AWD for now.

Thanks in advance.
Logged

jzdoghouse

  • New Member
  • *
  • Offline Offline
  • Posts: 1
Re: Dropping out of gear in 2WD
« Reply #8 on: 03/04/13 06:13 AM »

I am having similar problems with my 2005 Avalanche. I start in gear but when i take my foot out of it it goes into what looks like neutral - from there i have to let sit for about 15 minutes before i can get it to move again. Only thing different is when it first happened i could only role  the truck forward and not backwards, it made no difference if it was in AWD, 2WD, 4WD or 4L. In the last week i now have both the tach and the speedo that are jumping - reading correct but jumping - i think this is just by chance but don't know.

Any help would be appreciated.
Logged

plips_2002

  • Member
  • **
  • Offline Offline
  • Posts: 23
Re: Dropping out of gear in 2WD
« Reply #9 on: 12/06/16 07:02 AM »

Hello all, I know this is an old thread but I'm trying my luck. I am having the same exact problem, AWD its fine but 2WD it sometimes shifts to neutral. I have no service 4WD message and cannot put the truck in 4LO. I would also like to know what parts you got that fixed the problem. Thank you.
Logged
2005 Z71, Red with Cladding

Chaos67731

  • Full Member
  • ***
  • Offline Offline
  • Posts: 42
Re: Dropping out of gear in 2WD
« Reply #10 on: 09/12/17 10:57 AM »

Like the user above me, I know this is a long shot seeing that no one answered him.  But do you happen to remember what the fix was? I have been having the same problem.
Logged

uronlydreaming

  • New Member
  • *
  • Offline Offline
  • Posts: 1
  • I love the Chevy Avalanche
Re: Dropping out of gear in 2WD
« Reply #11 on: 03/17/18 12:23 PM »

SAME HAPPENED to me with the truck dropping into neutral while going either up or down into 2nd gear.  My mechanic said it was the transfer case, cost me $2400 then $900 for the module.  Problem persisted.  Couldn't take the bs anymore so I took it to Chevy.  Their diagnoses said BAD SOLENOID PACK, they recommended a rebuild and installe for about $6k total... so you know what I was thinking.  All the while, I created a workaround for the problem that worked EVERY time... I would simply start from first and shift up when *I* felt there was enough "energy" to make the shift.  Apparently, with the bad solenoid pack there was something to do with there not being enough voltage to make the shift into 2nd.  So by shifting manually, I could get the rpms up and shift into 2nd successfully at a higher rpm.  Otherwise, the thing drove fine.

I never got that problem fixed but my tranny got puffed a year or so later.  I'm about to have a reman installed.  I'll let you know how that goes.  (can ya tell im not a mechanic?)
Logged

Buki5

  • New Member
  • *
  • Offline Offline
  • Posts: 1
Re: Dropping out of gear in 2WD
« Reply #12 on: 04/10/18 12:41 PM »

Same problem on an ‘05 Z71.  The “Encoder motor” on the transfer case was failing.  New one installed good as new.
Logged
Pages: [1]   Go Up
 

Page created in 0.108 seconds with 24 queries.