Clunking sound when starting out in my f-250

Discussion in 'Trucks and Trailers' started by cos, Jun 25, 2003.

  1. cos

    cos LawnSite Addict
    Messages: 1,253

    My 96 f-250 7.3 PSD is clunking when I start out from a stop. When I start out from a red light or stop sign, it seems that when the wheels get to a full revelution or 2 that a clunk is heard and felt. I am thinking U-joints or even motor mounts. My first and initial thought is motor mounts, because it is felt and seen from the hood.

    Any ideas of what it could be?
  2. June Bugs Mowing

    June Bugs Mowing LawnSite Member
    Messages: 10

    I would say a u joint because of the clunking sound can travel thru the frame of the truck and make it sound like it is in the front.The u joint is the cheapest to do first.If you wanna check your motor mount just try to jack the one side of the motor up and see if the rubber is torn.good luck and hope this helps.
  3. I am Me

    I am Me LawnSite Member
    from D/FW
    Messages: 72

    take a look at your rearend. I had the rearend on my chevy go out and it sounded the same way. when you start you will hear a loud clunk, you may also hear a "whup, whup" sound as you go down the road.

    I initially thought u-joint, but ended up being a broken tooth on one of the gears. Cost me about $750.00 for a salvage yard rear end. New they wanted $2500. Mine was a 3/4 ton. :(
  4. FrankenScagMachines

    FrankenScagMachines LawnSite Platinum Member
    from IN
    Messages: 4,739

    When you stop from going forward in a parking lot or driveway, then let off the brake a bit but still on it some, put it in reverse and if it clunks pretty good as it's taking off in reverse it possibly is the U-joint... Just an idea of an easy way to check it. The motor mounts don't necessarily have to be replaced, they might just need tightened.

    K eep
    I t
    S imple
    S tupid

    LOL I live by that! Look for the simplest thing first.

    Good luck w/ it Cos.
  5. cos

    cos LawnSite Addict
    Messages: 1,253

    I failed to mention that too, BHB (Thanks). When coming to a slow and stop it also clunks. It has about 90,000 miles.

    I will take a look at the u joints. Hopefully they aren't the ones that need a press to remove. :( UJoints were easy to replace on the older trucks, now they make it a shop replacement more and more.

    I also had a tooth go in my dump truck once. And, I remember that sound. (ouch) I think it is and hope it is just the u-joints. It's just weird how the sound comes from the front of the truck.

    Thanks for the replys.
  6. FrankenScagMachines

    FrankenScagMachines LawnSite Platinum Member
    from IN
    Messages: 4,739

    I don't know alot about this stuff but it ALMOST seems like it could POSSIBLY be something in the brakes since you said it does it when stopping? Like when it does it when you take off they are making the noise as they are releasing their grip? Just a thought... I'd still go to the U joints first.
    good luck
  7. When you are checking U joints check for play in the pinion shaft. Could be a pinion bearing going and it makes same clunk as bad U joint.
  8. cos

    cos LawnSite Addict
    Messages: 1,253

    I went out and grabbed the drive shaft today and felt no play in the U-joints. I am seriously now starting to wonder. Is there a "real" way of checking the u-joints?
  9. June Bugs Mowing

    June Bugs Mowing LawnSite Member
    Messages: 10

    Did you block the wheels to take off the pressure on the shaft?

    SCAPEASAURUSREX LawnSite Senior Member
    Messages: 835

    If its coming from the front end.. I would first jack up the front end and support it by the axle or frame so the wheels are clear.. And then check the wheel s for play.. like warn or loose wheel bearings or bad ball joints... The F250's are notorious for ball joint wear , especially on the passenger side...

    Then I would pull the wheels and check the brakes, make sure the pads arnt messed up or a caliper hasent come loose ... Never know..... Then check the hubs... and the u joints for the front axxle shafts.... havent had them go bad myself but have heard of others having problems with them.... The hubs I have had go bad , but it was a continuous thumping / grinding sound...

    Do you feel it in the pedal ??? Is the front end jumping or bouncing when this happens ??? Try to see or feel what exactly is happening and where and youll be able to better narrowit down... But if you see th e front hood moving my guess would be the front end not the rear....

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