Hey, can anybody tell me what their general feeling is of my small problem (that might turn into a huge one if I don't figure it out)?

About a month ago, I noticed that my truck had begun making a cracking sound when I started off. It doesn't happen if I accelerate gently, only if I push the gas hard.

It's not my canopy. The box is tight. The exhaust piping is tight (brand new cats, muffler and piping only 6 months ago). The driveline ...could it be?
Could it be coming from inside a cat? It wouldn't do any good to put it up on blocks. It only does it when under load.

I did notice that, about the same time, my truck started doing something else. (Automatice transmission.) Whenever I start off, I push the gas and it seems to take a half a second before the gears kick in and the truck starts pulling itself forward. I'm going to pull the diff cover. Just need to get some of the proper oil (and apparently some special additive that Ford puts into it). I'll be checking the ring gear, etc. to see if i've chipped a tooth. But this cracking doesn't sound like something that could be coming from inside the diff. It's too loud. Leaf springs are tight. Brakes are redone 6 months ago, and then just yesterday, I changed the spring kit since I hadn't done that six months ago.

It's nothing extreme. It's not loud enough to be embarrasing, but I am concerned that there is something wrong between the tranny and the diff that is causing this. U-Joints are sound.

Any thoughts?
Thanks in advance.
Daniel

 

A seized U-joint can cause a big crack or snap noise. Usually the only way to tell if it's seized is to remove the driveshaft to check it.
While you have the driveshaft out put some grease in the splines in the slip yoke where it goes into the transmission or transfer case.

 

Yes, I believe you are right about that.
I've had 2 new U-joints sitting in the cab of my truck for 3 months now, but I never installed them because I figured that since there was no play in the U-Joints...no problem. I forgot to think about the other side of things...not enough play/siezed.
The new U-Joints are going in this Friday. The diff cover will then be pulled and an inspection done on the rear end. This will probably uncover some wonderful wear on the back end. Pinions, ring gear, etc. are all probably gone. Nice eh.

 

Let us know what you find.

 

Having the crackling noise also. Was suspecting a problem with the drive shaft perhaps coming apart. Has that ever happened. There is some play in the from universal joint but the noise cannot be pinpointed to that spot. Instead it seems to be coming from somewhere along the driveshaft

 

Hi gwrooster and welcome
A seized or worn u-joint can cause the noise and sometimes the noise travels throughout the shaft which makes it hard to pinpoint. If the u-joint has more than just a wee bit of play it's shot and needs to be replaced. If you pull the driveshaft out you can probably tell pretty easily if the u-joint is where the noise is coming from or not.

 

Right on target, replaced the universal joints and the noise disappeared. Gotta love this site.

 

Thanks for letting us know what fixed it

 

I've got the same kind of noise, but mine happens from 0-5mph. Could it be the same thing (u-joints)? I have a 1999 5.4 4x4, but it sounds like it coming from the front. I also hear crackling at idle, out of gear, before and after it's warmed up and definitely sounds like exhaust. I think they're two separate issues though.

 

A couple of questions about work along the driveshaft:

1) What type of grease should be used for the splines of the slip yoke? The Service and Parts depts. at Ford were no help on this.

2) Is there a bellows that goes over the part of the slip yoke that is exposed? Mine doesn't have one, so I was wondering if it tore off at some point, or just never existed. The Service and Parts depts at Ford was no help on this.

3) How do you get the U-joint off? I think mine is corroded in place. I tried knocking it with a hammer, shooting it with WD-40, and still ended up breaking a C-clamp trying to compress the bearings.

Thanx, Mike

 

mizzleman it's pretty easy to remove the driveshaft to check the u-joints so that's where I'd start. Quite often you cant really tell what shape they are in until you remove the shaft.
dansbro your dealer should stock (well at least mine does) some special teflon grease for in the slip yoke. It's quite an old part number that's been around a while. If you cant get that it seems that any good grease will work. It does wash out after a while though.
The rear driveshaft doesnt have a boot on it.
To remove the u-joint from the shaft takes a good u-joint press which is like a big c-clamp or lots of hammering and a vice but be warned that it's easy to wreck the shaft by hitting it wrong. It might be best to take the shaft to a shop and get the u-joint pressed in and out.

 

Racerguy,
My truck has 52k on it (I've had it since 40k). I've done u-joints before, but I wouldn't expect the u-joints go out that quick?