Loud klunk !! when shifting into gear .... NP 203 belt?

Discussion in 'Trucks and Trailers' started by velzey, Oct 17, 2000.

  1. velzey

    velzey LawnSite Member
    Messages: 6

    Hello greeting's from the Pacific Northwest ,Ive got a 77 GMC Camper Special : I have a loud klunk when i shift into any gear . It has a turbo 350 in it and i took the front driveline off thinking it was a worn U-joint . But no . Ive checked the rear ring and pinion and there is very little play there !! So , this is where im stumped . Does the belt in the NP 203 strech ?? making this loud noise???
    I can also hear it when im driving . let off the gas a little and it klunks , give it gas again and the same ...
    Will it break if it is the belt and take out the whole transfer case ???

    Well any input will be appriciated ....
    Thanks , Tim

    BUSHMASTER LawnSite Senior Member
    Messages: 519

    automatic . i had the tourqe converter bolts work lose and made a u joint or r&p slack sound
  3. velzey

    velzey LawnSite Member
    Messages: 6

    Well i checked the torque converter bolts and they are all tight !!!! Im going to put it on the rack this weekend and do some searchin...Thanks
  4. bandit_36

    bandit_36 LawnSite Member
    Messages: 49

    it's more than likely that it is play in your transfer case or loose splines on the rear drive shaft. You may want to pull the rear differential cover off while you have it up & check the teeth onthe ring gear & pinion.
  5. mike reeh

    mike reeh LawnSite Member
    Messages: 229

    no no no!!! Id bet money that its the front-axle ujoints.. put it in neutral, lock the hubs if you have em then turn the front driveshaft back and forth by hand and watch the axle ujoints very carefully..

    My last truck was a '77 np203 truck and it did exactly what you described, very badly, and that was it.. luckily my current '77 np203 had the part time conversion installed in the t-case and the whole driveline is *tight*

    good luck and keep us posted

    mike reeh

    OBRYANMAINT LawnSite Senior Member
    Messages: 555

    another possibility is a cracked flywheel , they will usually make noise when torque is applied

    i replaced one last year

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