Jump to content

The *thunk* when stopping

Laurence
 Share

Recommended Posts

Laurence Enthusiast

Laurence

Posted
Posted

I have a 2006 2500 Duramax 4x4. It has 100k miles on it. Occasionally when I come to a stop, it feels like someone is bumping in to me in the rear. This could be happening at the final downshift but I can't tell. The Allison is so smooth. I have no signs of any trans problems at all. Fluids are up. Temps are normal.

Any idea what this could be?

txab Senior Enthusiast

txab

Posted
Posted (edited)

Generally it can be a slip yoke sticking issue at the trans. Removing the shaft, lubricating the splines, will generally take car of the issue. They developed an upgraded slip yoke, out of nickel that was supposed to reduce this issue. If you search the site a bit, you'll find more about this

 

https://www.google.com/search?hl=en&as_q=slip+yoke+clunk&as_epq=&as_oq=&as_eq=&as_nlo=&as_nhi=&lr=&cr=&as_qdr=all&as_sitesearch=www.gm-trucks.com&as_occt=any&safe=images&as_filetype=&tbs=

Edited by txab
  • Thanks 1
Colossus Senior Enthusiast

Colossus

Posted
Posted

Slip yoke clunk was a common issue on the GMT-800 1/2 tons, and the solution was replacing it with a nickle plated slip yoke.  Did the 2500s have the same issues?  I don't recall that back in the day just on the 1500s..

Laurence Enthusiast

Laurence

Posted
  • Author
Posted

I have been doing some reading on this issue. Lubricating the splines is a GM recommended procedure for 4x2s only. GM does not permit this for 4x4s. ( Bulletin # 09-04-21-003B). The grease will migrate into the transfer case and contaminate the oil. Transmission fluid is supposed to lube the splines in this case.

I'll have to pull the yoke out and see if it is dry. What has been the experience of you 4x4 guys? Thanks for pointing me in the right direction.

 

  • 3 years later...
Laurence Enthusiast

Laurence

Posted
  • Author
Posted

The yoke is in great shape. No rust; nice and shiny. The splines had a thin film of oil in them.

I had the dealer look at it, thinking they would know what to do, All they could come up with is to use the GM special lubricant #12345879. It is a PTFE filled high temp grease. What will that do to the transfer case oil?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,981
    Total Members
    8,960
    Most Online
    Clark_Elite
    Newest Member
    Clark_Elite
    Joined

  • Who's Online   5 Members, 0 Anonymous, 384 Guests (See full list)

  • Latest Articles

  • Posts

    • B07
      p0449, p0446, p0451 Evap codes

      By B07 · Posted

      Glad I found this post before posting a question. My ‘09 has been throwing those codes and P0442. I replaced the gas cap as it was trashed to begin with and the purge solenoid valve under the hood but still get the code every now and then. Dealership said I need to replace the vent lines as the previous owner use cheap fuel line that feels more like a balloon. They also said the charcoal canister and the “canister vent solenoid/service kit” so it relocates the filter up by the top of the transmission. Vent solenoid is cracked as the previous owner just let it hang loose. Too lazy to put it back on its bracket. If I put it on there the hose kinks and I thinks causes a whistle when I fill up.  Only issue is the parts guys can’t tell me which one I need as it shows two styles. One has a jointed section. Which should I use?  Thanks.  I apologize for hijacking the thread
    • SwitchBladeSierra
      14-18 Sierra 1500 Heated Steering Wheel Help

      By SwitchBladeSierra · Posted

      UPDATE 3: Supposedly you need any cluster OTHER THAN a WT model cluster to have full steering wheel functionality. Went back to the part truck and removed the all terrain cluster, trim, and snipped as many wiring harnesses as possible to pull out the factory terminal leads if needed 😂 that poor donor truck…    As of right now I’m relying on Darth_Vader’s thread and YouTube videos. will update.  
    • PunchT37
      AFM Experience

      By PunchT37 · Posted

      Was commenting on the engine labs article on lifter failure.
    • Another JR
      Open Door Chimes When Key is Out

      By Another JR · Posted

      The “engine hours” display is there because the truck detects the key presence as you were thinking.   My first step would be to call a dealer service person and ask if this a known issue and how they deal with it. If you don’t get meaningful advice there, i would try a couple of DIY things before bringing it in for troubleshooting/repair.   It sounds like a mechanical key detection switch is stuck, but I have not actually seen what the internals look like. Maybe spray some Caig Deoxit (electrical contact cleaner) in the key hole and work the key in and out in case it’s an electrical contact cleanliness issue.  If that doesn’t work, next apply whatever lubricant GM recommends and work the key in and out a few times.    Good luck with it. 
    • Atlas
      AFM Experience

      By Atlas · Posted

      Carbon on valves would be the least of my worries on a light duty, 1500-series pickup with 357k provided the engine still ran halfway decently. Everything else is likely toast, on its way out, or has already been mauled to death by cheap mechanics and backyard fixes. Those kinds of trucks nickel and dime a guy to death.   I wouldn't think having the top end cleaned once or twice would be a big deal on a 5.3 but maybe it is?

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...