A Ford tech's take on "THE CLUNK" (THE ONE and ONLY CLUNK THREAD)

[FSM06]

I don't care if it improves my gas mileage, lol. I shouldnt be hearing it. If they can figure a way to make it keep doing it but I can't HEAR or FEEL it, GREAT !.... Good job Ford !!

If I had a 1987 Ford F150 and it started doing it at 217,435 miles I would STILL want it fixed.

If Ford is trying to figure out a "cost effective" fix and is waiting until everyones warranty runs out, they will get sued waaaay before that, lol.

I'll pay for the immediate fix, rather than drive with it for the next year or so.

HR, I did not mean to give you the idea that you should "learn to live with it" and I apologize if I came off that way. I truly hope FoMoCo can resolve this for you and I am sure that there is a fix due to the fact that not every truck seems to experience this, unlike the ranger thing I mentioned which affected all manual trans rangers. I just meant to say that there is not any detrimental mechanical effect to your vehicle in the meantime until they hopefully resolve it.

FSM

P.S. personally I feel it has to due with u-joint angles and how they change when coming to a stop. The softer suspension allows the nose of the pinion to "droop" or lower when braking to a stop. In some instances this may allow the operating angles of the front and rear u-joint to operate above 1 to 1 1/2 degrees. The u-joints then "fight" each other until the angle returns to normal. But hey, that's just a guess based on a few years of dealing with driveline angles. Could be completely out in left field.

 

[Jhawk]

I'd like to think that there would be no mechanical harm done to the vehicle but does anyone know that for sure? Its not like these Raptors have been driving around for very long. If in 5 years it turns out that this problem caused some premature wear somewhere who is gonna cover that?

 

[DocSpooK]

P.S. personally I feel it has to due with u-joint angles and how they change when coming to a stop. The softer suspension allows the nose of the pinion to "droop" or lower when braking to a stop. In some instances this may allow the operating angles of the front and rear u-joint to operate above 1 to 1 1/2 degrees. The u-joints then "fight" each other until the angle returns to normal. But hey, that's just a guess based on a few years of dealing with driveline angles. Could be completely out in left field.

Interesting theory, would that mean that a mid/top perch adjustment would cure the clunk?

 

[FSM06]

Interesting theory, would that mean that a mid/top perch adjustment would cure the clunk?

A perch adjustment would not change a u-joint angle at the rear shaft. Rolling the rear axle or shimming the transmission mount would be necessary to change the angles.

FSM

 

[JP7]

A perch adjustment would not change a u-joint angle at the rear shaft. Rolling the rear axle or shimming the transmission mount would be necessary to change the angles.

FSM

Agreed - I'm re-thinking the idea of a trac-bar type setup for the rear like I had on my last Bronco. A 2" x 2" HSS that was fit to the axle housing (to replace our stock spacer) and ran about 18" forward ending at the front leaf shackle where a rubber bump stop provides contact with the underside of the shackle. It completely solved the axle wrap problem in that truck, so maybe it will work in this one too.

 

[HoustonRider]

Guys, I found "The Clunk"......

I have a video of the Slip Yoke. Its dark underneath, but you can make out EXACTLY what happens when the "Clunk" is heard.

Basically, its when the Slip Yoke Goes IN/OUT of the trans. The Slip Yoke is designed to slide in and out of the trans rear. I don't know how long this Yoke is, but it moves a few inches either way. When the Yoke is "pulled away" from the tranny, usually no noise is heard.

When the Slip Yoke is slid BACK IN over the Spline, thats when the noise is heard. you can SEE the Yoke "skip/jolt" back over the spline, and the noise that follows. Sometimes you see only ONE SKIP, and you hear ONE clunk (or rub). Sometimes you see TWO skips going back into the tranny, and you hear TWO rubs, or clunks.

In all of these instances you also see the transmission itself jolt once or twice, coinciding with the noise heard.

So, its no lube on the spline, or lack of. the reason the noise comes back is that its possible that fluid or heat dissipates the grease over a few hundred or more miles and after it dries up, the clunk is back.

The weight of the truck is FORCING the YOKE back over the dry SPLINE. Thats the noise you hear and feel.

I have seen a few posts on other forums where guys have greased the shit out of the yoke and spline on older F150s and F250s, then cover with a boot, and grease inside that. It does seem that these guys are still having to re-grease this every few thousand miles in some cases, so thats still not the long term answer.

Anyway, here's the video, sorry for the lighting, I can correct it later.

YouTube - The Clunk


Same video in 1/2 speed, and a little lighter. I'm gonna have to reshoot this for sure.

YouTube - The Clunk in Slo Mo - Ford Raptor or F150 CLUNK SLIP YOKE

 

[Sharky]

Guys like you are awesome. A little ingenuity and an affordable camera. Good work brother. I'm fortunate that my 2010 SCAB has no clunkage.

 

[BDRAG]

I have a video of the Slip Yoke. Its dark underneath, but you can make out EXACTLY what happens when the "Clunk" is heard./QUOTE]

Sweet Video. GoPro or what? Anyway, yest this is the problem and has been for awhile on some Ford Trucks. I think Ford KNOWS this is the culprit and the lube is important but as you mention it NEEDS to STAY PUT to work. I hope Ford watches your clip. Its very clear and shows whats involved.

The Ford Engineers need to figger out some sort of Teflon or maybe MAGNA PLATING or TUFF RAM or something to permently coat the splines on the tranny and the Yoke. Make the surfaces slippery and then add the grease. Or maybe Ford needs to install a Ball Drive like the front drive shafts use. Or make it a massive rubber somdabitch! HAhahaaaaaa. They will fix it, give them time..

Your video should convince anyone worried about the clunk that nothing is gonna bust or fly apart. Its just a metal on metal bind that moves back and forth causing noise. The suspension, bed and the whole drive line just magnifies the noise. Great Video........

BDRAG

 

[IRONMAN]

Great video!

 

[HARLEY6LF250SDU]

Damn, looks like one of "MY" Raptor trannys, attached to a Black 2011 Raptor I Sold to a customer in Southern Texas. SWEEEET!!


lol randy