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Clunking noise, need help

Discussion in 'The Garage' started by sleeper_dave, Dec 20, 2004.

  1. sleeper_dave

    sleeper_dave Registered Member

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    Don't know if this is the right forum for this, but it seems to be the only one i can post in anymore.

    I have a '91 Suburban 1500, 4x4, 350 TBI. Gov-lock rear end.

    When i'm moving, my truck will clunk. It will clunk once, then a short time later clunk again. It's worse when it's cold. I can't tell for sure, but it seems to be coming from the rear end. U-joints are new. Does it mostly when i'm on the gas, and more frequently when i'm on the highway, but it does it when i'm coasting and when i'm on side streets too.

    Is this indicative of a failing gov-lock?

    Thanks

    Dave
     
  2. sleeper_dave

    sleeper_dave Registered Member

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    Anyone? This thing sounds like it's about to explode, but when i took the diff cover off i couldn't find anything wrong.
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    You may not see anything wrong now , but if that Gov Bomb has any slop in it you will lose it sooner or later , and it won't care how far away from home you are :xmas:
     
  4. sleeper_dave

    sleeper_dave Registered Member

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    I just want to be sure that's the problem. It can blow up, i'm fine with that. I just want to know! But i can't seem to find anything else that could be causing it.
     
  5. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Pinion bearings , ring gear , the center section , a lot of stuff could wrong :xmas:
     
  6. K5Jimmy

    K5Jimmy 1/2 ton status

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    If it sounds like something binding and releasing (chain slipping sorta) feel for it on your TC shifter. Pull the tailshaft housing off your TC...there should be a snap ring right against the bearing you will see in the speedo gear housing...if this snap ring is broken, it will allow the mainshaft of the TC to wander back and forth....cheap fix, (dealer here wanted $8 for the friggin snap ring, I bought 5 for $1 each another place) but something caused it to break...

    Also if the teflon pads on the mode fork and/or range fork are gone (worn completely off) it may cause a similar prob...TC tuneup (bearings, seals) is way cheap and fairly easy...I just went thru all this with my 89....Like so many others on this board, I ain't a mechanic...I just work on stuff...TC is basically snap rings and gently tapping bearings in and out....
     
  7. sleeper_dave

    sleeper_dave Registered Member

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    Thanks, i'll definitely take a look at that tailshaft.
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    Are you referring to a NP208??

    My 82 K20 has made a few "bangs" once in a while,made me wonder if it has a bad gov-loc rear end too--but the transfer case seems to not disengage in 2 hi--the front shaft is still turning,and delivering power to the front axle even in 2 hi--think its that snap ring or the shifter forks in my truck making it do that??..
    ( I tried adjusting the linkage--its ok)

    I have another T-case (NP208) I bought at a swap meet cheap,hopefully a good one,for a spare--I'm hoping it will make it thru the winter as is,so I can fix it when its not so cold,and I need it to plow....if you have any photos of your case apart,I'd like too see them,in case I have to do some "surgurey"!!..:crazy:
     
  9. sleeper_dave

    sleeper_dave Registered Member

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    well whatever it was on my truck just blew up. And it's not the rear end, because it's making nasty grinding noises and the driveshaft isn't turning.

    I was on my way home from work, and all of a sudden there is a nasty grinding noise that gets louder when i hit the gas, and the truck isn't accelerating. So i pull over, stop, then i try to go again, and everything is fine. Drove home, no clunk or anything. Drove back to work, the same thing happened. This time, i noticed that when i hit the gas, the speed on the speedometer did not increase. Pulled over, stopped, and all was good again.

    When i got to work, it started doing it again at low speeds. I couldn't tell if it made a difference what gear it was in. I stopped at a stop sign and had no forward mobility. I tried putting it in neutral, nothing changed, i tried putting it in park and got the additional grind from the parking pawl trying to engage. i shut it off, started it up, and it worked for a minute, then did the same thing. i put the parking brake on and got out of the truck, to check the driveshaft, it was not spinning. I shut the truck off, started it, and barely got it into a parking spot, then shut it off again.

    Then i tried 4x4. I put it in 4x4, started the truck, and was able to drive it around the parking lot. I couldn't discern any grinding, but there might have been something. the truck did the normal jumping thing when i turned it in 4x4, so i know both the front and rear were getting driven. When i popped it back in 2wd it was still fine, and i parked it again with no further incident.

    So, what is my problem? Tranny or transfer case?

    This sucks, because my other car is RWD with summer tires, and is parked for the winter. And we're getting a snowstorm tonight.

    BTW it's an NP241 in my truck.
     
    Last edited: Dec 22, 2004
  10. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Transfer case for sure it sounds like now . I still would get rid of the gov loc , but this sounds like transfercase :frown1: They are simmilar to 208's , so the range fork could be gone :confused:
     
  11. RustBuket

    RustBuket 1/2 ton status

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    Mine used to pop out of 4-lo/4-hi to neutral all the time. I fixed mine but adjusting the linkage. You could try that? Its a free fix if it works. Sounds like it could be something a little deeper inside tho....
     
  12. sleeper_dave

    sleeper_dave Registered Member

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    So, does anyone think this could be the transmission, or is it probably the transfer case? i haven't been able to check the fluid on either yet. I have secured a garage to work in (i helped a buddy clean out his garage a couple weeks ago, it's 2 cars wide by almost 2 cars deep, so plenty of room for the burban).
     
  13. RustBuket

    RustBuket 1/2 ton status

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    Well if its an auto, I doubt its the tranny. Autos generally don't grind and such, they slip.
     
  14. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Couldn't be the tranny then , Auto's usually work or don't , or they lose a gear or two , or just slip . When I lost my transfercase , it only grabbed 4wd lo , drove home a couple miles doing 25-35 mph ( 33's and 3.08's ) :frown1:
     
  15. K5Jimmy

    K5Jimmy 1/2 ton status

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    Tc for sure...mine did pretty much the same thing only not as drastic..

    Short end of a long story....In my opinion....If you replace it with a salvage yard/used unit, seems that you may be buying more of the same problem....salvage 241's here are going for $300 neighborhood....the one's I have found local from rebuilders are $600-$700...found a place on the internet for $600 shipped....

    Bearing kit was $111, range fork was $58, chain $80 plus shipping...that's about $250 plus a tube of gasket maker and the cost of a good snap ring plier...takes about 30 minutes to drop it (80lb)....about 3hrs to dissassemble/reassemble, and another 30-45 to reinstall...keeping in mind that you are Gently tapping bearings in an Aluminum case (I use a 3/4" wooden dowel, and I have a 1/2" solid brass dowel)...figuring I ain't a mechanic, but I do have a heated shop and air tools...I now know for certain what I have in my TC as far as wear and new parts..

    Bolts are metric...4 bolts to drop the DS, 4 nut/bolt to drop the skid plate, 6 to free it from the tranny adapter, unscrew the speedo cable....wiggle it out about 4", writhe in pain for 2 minutes when you realize you have dropped 80# on your chest...wriggle out from under the truck completely covered in tranny fluid, spread some newspaper on the kitchen floor, and have at the sumbitch....it really ain't that hard

    My TC has about 140K on it, and I thought it was in good shape...tearing it down and finding the range fork worn to a knife edge was a surprise....even tho the chain was tight, I found minor damage to the inside where it had evidentally boogered itself when the snap ring broke and allowed the shaft to wander and misalign with the lower front output gear somehow...

    If/when you order parts, I used www.nationaldrivetrain.com....they ship out of Atlanta and Chicago, and are direct distributers for Motive gear who are wholesale only.....www.blumenthalmfg.com ships from OKC...I got a good exploded view and parts list from www.motivegear.com

    Your range fork should be one stamped 338, which makes a difference in the parts number for some reason...I was told it was used only for a couple years in 89-90 and is a Suburban application (?)....I feel certain that your range fork is worn enough to warrant replacement if you go to the trouble of tearing it down....

    Feel free to emial me at K5Jimmy@yahoo.com, and I'll give you my cell number if you would like to talk directly about the issues I ran into or whatever....

    Good luck
     

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