Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Weird grinding noise when decelerating

Discussion in 'The Garage' started by PsychoticDeadGuy, Sep 16, 2005.

  1. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

    Joined:
    Jan 8, 2005
    Posts:
    753
    Likes Received:
    0
    Location:
    Fairfield, California
    Ok, i asked this question a while ago and everyone told me to change the u-joints...so i changed the the whole rear driveshaft and new u-joints. the noise is still there...the tranny has enough fluid and so does the trans case. i am thinking it could be the chain in the np208...it only does it when i let off the gas...it could be a long grind or it could be on and off...help please.
     
  2. coptezr

    coptezr 1/2 ton status

    Joined:
    Jan 13, 2005
    Posts:
    342
    Likes Received:
    0
    Location:
    Kennewick,Washington
    mine did that too and i shaved my gears.
     
  3. outlawtorn

    outlawtorn 1/2 ton status

    Joined:
    Jul 21, 2004
    Posts:
    365
    Likes Received:
    0
    Location:
    Box Elder, SD
    my 203 did that... I was told it was slack in my chain.
     
  4. chevyin

    chevyin 1/2 ton status

    Joined:
    Sep 14, 2005
    Posts:
    1,324
    Likes Received:
    0
    Location:
    Pismo Bch CA
    grinding

    Mine did that allso, and it turned out to be the pinnon gear had come forward and was hitting the spider houseing when you took foot off gas. It was 12 bolt GM.
     
  5. MTMike

    MTMike 1/2 ton status

    Joined:
    Feb 10, 2005
    Posts:
    2,992
    Likes Received:
    0
    Location:
    Billings, Montana
    Mine did that with 12" of suspension lift. Put stock 56's & a shackle flip back there and it quit. In my case, it was improper driveline angles.
     
  6. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

    Joined:
    Jan 8, 2005
    Posts:
    753
    Likes Received:
    0
    Location:
    Fairfield, California
    ok, my rear end is good. how much if any should i be able to turn my driveshaft while my tranny is in park...(tires off the ground)?
     
  7. Leper

    Leper 1/2 ton status

    Joined:
    Feb 18, 2005
    Posts:
    4,437
    Likes Received:
    0
    Location:
    Dallas Baby!!!!
    Try putting the truck in neutral before you slow down and see if it gets better or worse or stays the same.
    Doing that can point you in the right direction
     
  8. 81jimmyslt

    81jimmyslt 1/2 ton status

    Joined:
    Jun 5, 2003
    Posts:
    1,643
    Likes Received:
    0
    Location:
    So Lake Tahoe (Rubicon), CA
    Mine is doing the same thing (NP 208) My shaft is too long, and on deceleration and braking hard I get grinding. I'm pretty sure it's coming from the tcase. I'm going to push the axle back for now and check the housing.

    Someone mentioned slippng chain? :thinking:
     
  9. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

    Joined:
    Jan 8, 2005
    Posts:
    753
    Likes Received:
    0
    Location:
    Fairfield, California
    well, the easiest fix so far seems to drop the t-case down a little bit. i ran it with a 4" lift and i lowered the t-case down about 1/2" and there were no problems. well now i have instead of blocks, i have ORD zero rates, and shackle flip and a 14bff which raised my truck up about 2 more inches from where it was...i am hoping it is the driveshaft angle...i am going to make a new spacer for the tranny mount to bring it down about 1/4-1/2" more...i hope it will work...i wont be able to do this until monday so i will post up my story when im done.
     
  10. 81jimmyslt

    81jimmyslt 1/2 ton status

    Joined:
    Jun 5, 2003
    Posts:
    1,643
    Likes Received:
    0
    Location:
    So Lake Tahoe (Rubicon), CA
    anyone else have any ideas?
     
  11. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

    Joined:
    Jan 8, 2005
    Posts:
    753
    Likes Received:
    0
    Location:
    Fairfield, California
    i will make the spacers tonight and will either put them on later tonight or tomorrow and i will let you know how it works
     
  12. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

    Joined:
    Jan 8, 2005
    Posts:
    753
    Likes Received:
    0
    Location:
    Fairfield, California
    well, i put some spacers to lower the crossmember of my tranny which in turn lowered my t-case and made the angle for my driveshaft alot better. the spacer was only 3/8" thick but there are no more vibrations or grinding sounds...i feel much better now about it. hope this helps out someone else...
     
  13. MTMike

    MTMike 1/2 ton status

    Joined:
    Feb 10, 2005
    Posts:
    2,992
    Likes Received:
    0
    Location:
    Billings, Montana
    Glad to hear! :waytogo:
     
  14. 81jimmyslt

    81jimmyslt 1/2 ton status

    Joined:
    Jun 5, 2003
    Posts:
    1,643
    Likes Received:
    0
    Location:
    So Lake Tahoe (Rubicon), CA
    I moved my axle back 1.5" but I still have grinding on deceleration. When I brake hard it's awful, grinds so much.

    Any more ideas?

    I'm going to lower my t-case again but only use the spacers on the t-case.
     
  15. PsychoticDeadGuy

    PsychoticDeadGuy 1/2 ton status

    Joined:
    Jan 8, 2005
    Posts:
    753
    Likes Received:
    0
    Location:
    Fairfield, California
    its from the rear end coming up a little and screwing up your drivline angle at the t-case...lower it about 1/4-1/2" and it should go away.
     
  16. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,073
    Likes Received:
    485
    Location:
    Grand Rapids area
    It could be just from mismatched driveline angles, but it could also be that you have a U-joint maxed out for angle. When you decelerate, the back of the truck comes up and this increases the U-joint angles. You would be able to see shiny spots in the yoke ears.

    I was also going to suggest a loose pinion nut, but if lowering the T-case helped, that probably wasn't the problem.
     
  17. down4thakrown

    down4thakrown 1/2 ton status Premium Member GMOTM Winner

    Joined:
    Aug 5, 2003
    Posts:
    1,760
    Likes Received:
    75
    Location:
    flagstaff,az
    i got the same thing wrong with my 205.i was thinkin maybe it was just a little slop in the gears and them just catchin up with each other. other ck5 members said the same.
     

Share This Page