My Superduty recently started clunking when I accelerate from a dead stop. The harder I hit the gas,the harder it clunks. I unbolted the driveshaft from the rear end and the yoke slides easily. Tranny mount looks tight. Could it be the front driveshaft? Sometimes when I brake hard and the truck comes to a complete stop it will do it too. Any ideas?

 

Try this link.....

2004 F250 Slip Yoke Service

 

My slip yoke slides fine. U joints are tight too.

 

I bought a 2010 F250 that had the same problem. The dealership said it was strange and after trying several fixes, finally deferred to Detriot to diagnose. After six trips back to the dealership, they eventually decided it was "normal" even though they originally agreed it was not. When I mentioned invoking the Lemon Law, they bought the truck back and gave me a sweet deal on a 2011 F350 Dually. The new truck has 18,000 miles on it and has not yet developed the "normal" clunk. Unless your dealer has an extraordinary service department, you will be in for continued clunks.

 

It's not the slipping, it's the lack of grease, try greasing it up.

 

Ok ok I'll grease it. I just figured that if it was sliding easily, it didnt need grease.

 

For what it's worth, packing it with grease made no difference on my 2010. That was the second trick the dealership tried, right after checking the torque on all the driveline fasteners.

 

in the pictures of the slip yoke it looks like there is grease in there, mine looked like there was too. I did go away after greasing it up surprisingly. I know it will come back eventually, but it's the way it was designed, so the only cure is grease. So far it's been two years but only about 8K miles.

 

He also has a 03 with 100k plus and if it just started doing it, more than likely it needs the grease, mine had about 67K when it started to do it.

It's not like he's going to take it back to the dealer for warranty issues like you did!

 

They will slide in and out fine even when low on grease. When engine torque is applied, there is enough friction to keep it from sliding and thus the 'clunk'. Regreasing should do the trick. I bought a tube of special grease from Ford and would have to grease the slip joint every 50k or so. When I ran out I starting using Super White Grease from NAPA and it seems to last a lot longer (and costs less too...).

Make sure you chock your wheels before you remove the drive shaft. Some very smart mechanics have overlooked this step an ended up in the hospital. Safety first.

 

Outstanding point.......

 

My truck is a 03 F-350 with 113,000 miles on it. Probably never been greased. The only grease I have is wheel bearing grease. Will that work? Its water proof for boat trailers.

 

You have a 96 in your profile..lol

It's all I usually use for just about anything that needs grease.

 

I think it will work fine. It's blue right? The Ford stuff is blue also so at least it's the right color.

Lube up the splines nice and good and then apply a little bit in the receiver as well. Not too much though, you don't want to pack it full because the pieces won't be able to slide back and forth as needed. I usually slide the splined shaft in as far as it will go just to confirm there isn't too much grease and fasten the other end to the pinion yolk.

 

Ok so I just did it. I slide the yoke off and covered the shaft with grease. But when I slid the yoke back on it pushed most of the grease back off. So I guess we'll see if it works.,