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    Results 1 to 15 of 15
    1. #1
      Join Date
      Jul 2008
      Location
      Maple Ridge, BC,Canada
      Posts
      113

      Rear end problems??

      Took the car out for a spin today and a new issue, oh joy. When shifting the 700R4 from 3 to 2 or 2 to 1 when not under load and low speed down shifting I get a big clunk in the rear end. One time when shifting when not under load, just coasting and going 3rd to 2nd and back to 3rd a few times listening for the clunk it seemed like the rear gears would not mesh, I got a bucking clunk clunk then it went away and engaged. Also when turning ( mostly left) it feels like I am driving over a rough surface, like gravel. Trans was serviced 2 weeks ago. 100%. U joints front and back replaced 2 months ago. Rear is full of fluid. Would adding more gear additive resolve, or drain all fluid and put in new? Current fluid is a year old. Broken spider gears or worn positraction clutches? I have no experience in rear/diff work. Any advice on assessing this?

      Thanks

      70 Nova - 406 sb -488 HP/504 TQ-3:73's
      http://s66.photobucket.com/albums/h266/steelratnova/


    2. #2
      Join Date
      Nov 2006
      Posts
      456
      What rear end do you have and what differential is in it? Do you have leaf springs? What type of traction devices do you have?

    3. #3
      Join Date
      Jul 2008
      Location
      Maple Ridge, BC,Canada
      Posts
      113
      8.5
      eaton posi
      leaf springs
      slide a links
      70 Nova - 406 sb -488 HP/504 TQ-3:73's
      http://s66.photobucket.com/albums/h266/steelratnova/

    4. #4
      Join Date
      Apr 2004
      Location
      Cedar Rapids, IA
      Posts
      999
      Kinda sounds like an issue I had with my rear. I didn't get the pinion preload correct when I put my rear together, and would get a very loud clunk when I would accelerate or decelerate. I didn't have a gravel road feel when turning though.
      Some times I'm fast sometimes I'm half-fast

    5. #5
      Join Date
      Jul 2008
      Location
      Maple Ridge, BC,Canada
      Posts
      113
      Quote Originally Posted by rohrt View Post
      Kinda sounds like an issue I had with my rear. I didn't get the pinion preload correct when I put my rear together, and would get a very loud clunk when I would accelerate or decelerate. .
      Hmm, I wonder if my rear shifted and threw out the pinion angle. I was out last week and the car hooked real hard on nice new black asphalt, I thought I felt a big clunk in the back as it hooked. I have checked leaf spring mounts front and back, tranny mount/crossmember and engine mounts. All are A OK.
      70 Nova - 406 sb -488 HP/504 TQ-3:73's
      http://s66.photobucket.com/albums/h266/steelratnova/

    6. #6
      Join Date
      Apr 2004
      Location
      Cedar Rapids, IA
      Posts
      999
      I was able to put the car in park and roll the back wheel back and forth enough to get it to clunk. Thats how I knew the sound was coming from the rear and not something else. I could feel nothing at the pinion with the drive shaft off. I couldn't move it in or out and it felt fine spining it around. May not be your issue but its easy to check.
      Some times I'm fast sometimes I'm half-fast

    7. #7
      Join Date
      Jul 2008
      Location
      Maple Ridge, BC,Canada
      Posts
      113
      thanks rohrt, will try that.
      70 Nova - 406 sb -488 HP/504 TQ-3:73's
      http://s66.photobucket.com/albums/h266/steelratnova/

    8. #8
      Join Date
      Nov 2006
      Posts
      456
      Did you use the limited slip oil additive. and was it the GM or Ford additive? One bottle of GM additive should be enough to take care of that noise when turning. The other problems might be in the transmission or the suspension.

    9. #9
      Join Date
      Jul 2008
      Location
      Maple Ridge, BC,Canada
      Posts
      113
      Quote Originally Posted by big gear head View Post
      Did you use the limited slip oil additive. and was it the GM or Ford additive? One bottle of GM additive should be enough to take care of that noise when turning. The other problems might be in the transmission or the suspension.
      yes I do have limited slip additive. Rear fluids changed last summer. May be do for a change. My next plan of action was to dump all the rear oil, and put new in with new additive.
      70 Nova - 406 sb -488 HP/504 TQ-3:73's
      http://s66.photobucket.com/albums/h266/steelratnova/

    10. #10
      Join Date
      Jul 2008
      Location
      Maple Ridge, BC,Canada
      Posts
      113

      video of clunking

      ok, have removed driveshaft, replaced u joints, tightened every conceivable mount, bolt, bracket, etc. Motor mounts are good, tranny mount and cross member good. Slide a links tight, frame connectors tight, , shocks tight, all u bolts tight. leaf springs good and tight.
      Still has the clunk, so I thik it is in the rear. Here are 2 vids.

      http://www.youtube.com/watch?v=Dr1nL...layer_embedded

      http://www.youtube.com/watch?v=98BoE...layer_embedded


      Edit, video's were sent to a rear end guy, he says looks like the pinion nut that holds the pinion in is loose.
      That is why is good under load, but clunks when coasting or no load.
      70 Nova - 406 sb -488 HP/504 TQ-3:73's
      http://s66.photobucket.com/albums/h266/steelratnova/

    11. #11
      Join Date
      Jul 2006
      Location
      Pensacola, FL
      Posts
      1,263
      Country Flag: United States
      I'm no expert on rear ends, but I'd say something is definately broken or loose inside the diff. It seems it does this on the upshift & under braking, if I'm seeing that right. I'd pull the cover & have a look before that chunk goes out the rear cover...
      Take some pics once you get the cover off
      Scott

    12. #12
      Join Date
      Jul 2008
      Location
      Maple Ridge, BC,Canada
      Posts
      113
      the shifts are 2nd to 1st back to 2nd
      70 Nova - 406 sb -488 HP/504 TQ-3:73's
      http://s66.photobucket.com/albums/h266/steelratnova/

    13. #13
      Join Date
      Apr 2005
      Location
      USA
      Posts
      4,462
      Country Flag: United States
      Disconnect the driveshaft again and remove the rear diff cover.
      Feel for play between the gears ( too much backlash)and inspect the gears for damage or wear.
      It sounds like you have a loose pinion nut and the gears are noisy because of the changing preload on the pinion gear .
      Jeff Tate
      U.S.A.
      "The best thing about participating in these events is that you get to hang out with a group of intelligent like minded people who live to achieve things in their lives. You won't find a lazy, mean, or dumb bone in their bodies." Bret Voelkel, RideTech

    14. #14
      Join Date
      Jul 2008
      Location
      Maple Ridge, BC,Canada
      Posts
      113
      the culprit - broken tooth on ring gear :(
      70 Nova - 406 sb -488 HP/504 TQ-3:73's
      http://s66.photobucket.com/albums/h266/steelratnova/

    15. #15
      Join Date
      Nov 2006
      Posts
      456
      Looks like there might be some damage to the clutch pack too. The gaps between the plates are not even.





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