Clunk in my F250 when accelleating from a dead stop.

[cannesdo]

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.....

[Kevin_O_]

I had the same issue with my 2001 F350. Just like some others have mentioned, it's probably the slip joint on the 2 piece drive shaft. That's what my clunking noise came from everytime I took off from a dead stop. Ford sells a kit that comes with the Teflon grease and a new clip for the boot.Problem solved!!

[DirtyOil]

Red-Rover wrote:
There was a problem on some 2002 F250's for sure and perhaps the 2001? that dealt with this very symptom. Some came from the factory with insufficient lube (grease) in the splined U joint yoke that extended into the transmition. The drive shaft slides on the spline during acceleration.

LOL I have to laugh... had early F-series with same issue, while under warranty, I would take it to dealership, they said same pumped a pile of grease into the rear of the tranny and say "all good.. enjoy". Well back a second time, then a third time and once more... they put some heavy duty axle grease in there (I should mention this was all within a 5 week period) again they said "all good.." well a week later, clunking was back, crawled under the truck saw all kinds of grease "sprayed" on the underside. I pulled the drive shaft and low n behold... I found the issue. Seized universal joint at the "spline end" reinstalled driveshaft and drove down the to "all good" guys, asked for the service manager and together we had the truck on the hoist and the drive shaft was pulled. Asked the mechanic and service manager to grab the spline end and see if they could rotate it on the drive shaft... Nope! I asked how it wasn't noticed when they pulled it to pump all that grease into the tranny... that splined end is gonna flop around like a limp... when you pull the drive shaft. I wouldn't make a big deal out of this but the truck was under warranty and after the second trip they started charging me for the labour and grease... in the end I did get credited back and the universal joint was replaced under warranty.

[Dandy_Dan]

If you have a 2 piece driveshaft, check the carrier bearing and U-joints. In the truck I had it ended up being a bad U-joint so I had all of them replaced with greasable joints. Problem solved for me. This is just FYI for you in checking. Good Luck

[nofoolin]

You may also want to replace the oil soaked radiator hoses. Fuel and power str lines are much more resistant to oil than Radiator, or others other hoses carrying other fluids. It would be ashame to create a serious problem when the fix is so easy.

[nofoolin]

I agree that it may be the slip yoke is binding and causing your clunk. Easy fix, some companies used a specially formulated grease for longer service intervals.

I would also check the motor mounts as the slip yoke usually makes itself known under light throttle from a stop, or even pulling up to a stop. What you are describing takes a heavy throttle and is worsened by a turn. Check your engine and transmission mounts under load with an experienced helper that knows how to check the mounts.

[hotpepperkid]

kevden wrote:
The slip yoke on the tail of the transmission is common for this clunk. Might be worth looking into.

Yep need lub

[carringb]

Wes Tausend wrote:


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".


Wes
...

Yes. FILTER! haha must have been a slight disconnect between my brain and keyboard:E

Thanks for catching that;)

[Red-Rover]

There was a problem on some 2002 F250's for sure and perhaps the 2001? that dealt with this very symptom. Some came from the factory with insufficient lube (grease) in the splined U joint yoke that extended into the transmition. The drive shaft slides on the spline during acceleration.

[FishOnOne]

The leaky device is a filter. I've seen these used as a power steering fluid filter.

Also I agree with the comments about a dry slip yoke as the source of the clunk.

[kevden]

The slip yoke on the tail of the transmission is common for this clunk. Might be worth looking into.

[Greene728]

Ujoint. The leak has absolutely nothing to do with the clunking sound.

[Wes_Tausend]

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]

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]

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.