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cannesdo's avatar
cannesdo
Explorer
Jan 27, 2016

Clunk in my F250 when accelleating from a dead stop.

I've started noticing over the last few weeks that if I'm at a stop -- especially when pulling out of a business onto the main street where I need to really move to get into the flow of traffic -- there's a clunk from under the front end. It seems a little worse when I'm gunning it to turn right but also happens when I'm starting up from a red light. If I'm really gentle about it or already rolling it doesn't happen. Any ideas? It's always just one good clunk when it does happen. No grinding or other sounds.

I've had my ball joints replaced recently. Oil changed at Walmart two weeks ago. I have a good mechanic here who will investigate without charge.

From the research I'm doing it sounds like it could be a need for u-bolt tightening or grease on the splines.

Thanks.....
Tow Vehicles

17 Replies

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  • Greene728's avatar
    Greene728
    Explorer
    Jan 27, 2016
    Ujoint. The leak has absolutely nothing to do with the clunking sound.
  • Wes_Tausend's avatar
    Wes_Tausend
    Explorer
    Jan 27, 2016
    carringb wrote:
    That leaky thing is an inline transmission fluid cooler. Required by Ford if you've ever had the transmission apart, but a good thing to have anyways (I run the same one too preventively). A little seeping is noting to worry about, although trimming bit of hose on either end and new clamps should fix it. Most definitely not your source of the clunk.

    Did you check your hubs yet? The front axle isn't build as tight as the rear, so if you have the hubs locked in, the slop on the gears and axles can cause clunks when you are in 2WD.

    Brian,

    Are you sure you didn't mean oil "filter" instead of oil cooler? I'm not sure, but the leaky canister shape doesn't look like a "cooler".

    Also, the OP finally said he has 2WD in the post right above yours, so no 4x4 hubs to worry about. Nor half-shaft u-joints. Must be a 2003, or older truck, per 7.3L engine.

    I think the OP may be correct that the tranny drive shaft splines are dry, sticking and breaking loose under hard aceleration since Ford is noted for this. Unless something was left loose (can't imagine) when replacing ball-joints or other front end service.

    Offhand, will a Trac-Loc differential start to clunk if it is refilled and still requires the special additive? Some of his clunky starts were when turning.

    Wes
    ...
  • carringb's avatar
    carringb
    Explorer
    Jan 27, 2016
    That leaky thing is an inline transmission fluid cooler. Required by Ford if you've ever had the transmission apart, but a good thing to have anyways (I run the same one too preventively). A little seeping is noting to worry about, although trimming bit of hose on either end and new clamps should fix it. Most definitely not your source of the clunk.

    Did you check your hubs yet? The front axle isn't build as tight as the rear, so if you have the hubs locked in, the slop on the gears and axles can cause clunks when you are in 2WD.
  • cannesdo's avatar
    cannesdo
    Explorer
    Jan 27, 2016
    It's a ford f-250 7.3 diesel. 2WD.

    I also have a leak in the front and have traced it back to this thing:



    I think it's leaking out by the word "flow". Don't know if that's related to the clunk.

    Here's what it looks like if you slide under the front bumper, a little starboard of center.



    There is no fluid on the top side of the larger tube, just the right. And the right tube is just under the according looking thing that says "flow" on it.

    I'm guessing someone will know what that is.
  • Grit_dog's avatar
    Grit_dog
    Navigator II
    Jan 27, 2016
    U bolt tightening? Lol.
    Since you're not specific about the vehicle, I'll take a stab.
    Most drivetrain clunks from a dead stop are rear u joints or slop in the ring n pinion or spider gears.
    The latter is common in hi mile vehicles.

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