I have attributed the clunk i get from my truck when I bring it to a complete stop and go to take off again to the leaf springs being shot. Reason being for this is because when there is a trailer on the tongue or weight in the bed it is pretty much non existant. Now I have another question. After laying on the ground and having someone torque the truck up and down trying to see if I see anything out of the ordinary is going on I see number 1: the springs suck and number 2: when the truck is put in gear to go, the driveshaft does a little under a quarter turn before the tires actually start turning. Is this normal? Could this be my problem?

 

Sounds more like you need to grease your slip-yoke. Ford seems to have decided that a lot of joints don't need to be serviceable (greasable). The slip-yoke on your driveshaft is one of those points.

Symptoms:

It will happen only when you accelerate from a dead (or near dead) stop. It will feel like a sloppy driveline and 2 (maybe 3) little clunks and then everything seems fine.

Cure:

Grease the slip-yoke in your driveshaft. The best way to do this depends on your year of truck but here's the basic idea:

Your driveshaft runs from the back of the tranny to a carrier bearing (a bearing in a bracket that is mounted to the underside of the truck), then it makes it's way down to the rear differential. On that section of shaft should be a rubber boot held on by two metal bands, and that is the slip-yoke under the boot. Make chalk marks on your driveshaft and all connections (u-joints, etc.) to make sure that you re-assemble everything EXACTLY like it is now (the shaft is balanced and you can run into some nasty vibrational problems if you unbalance it). The goal is to slide the shaft out far enough to pull the two parts of the slip-yoke apart and get to the inside. You will need to remove the metal banding around the boot covering the yoke (some people re-use the bands, I just use big zip ties) and unbolt the rear of the shaft at the rear differential u-joint. Depending on what angle you can get after disconnenting, you may or may not need to drop the carrier bearing too. Use a rage and get all of the old, nasty grease out. If you haven't done this before, there will probably be very little grease in there (Ford was cheap on the grease). Put some grease on all the splines and the re-assemble everything.

This should solve your problem. Even if it doesn't, you weren't out but a couple of bucks worth of grease and a couple of hours of your time.

Just my .02. I hope this helps.

 

In case you don't know this already, here is the how-to on this.

click here

 

I forgot to add that I did this back in March. Is it possible I used the wrong grease or that it may have forced its way out into the rubber boot?

 

bump^^^^^^

 

No that's normal. If your foot is on the brake the shaft would turn about a quarter turn. Partly because it turns about 4 times for every axle revolution and partly because it is taking up the slack in the ring and pinion, spider gears, axle torque twist, tire squirm, and spring wrap up. Add even more if you have limited slip.

 

When I disassembled and greased the slip-yoke the smooth pull-outs only lasted a couple of months. I then did the mod to add the grease fitting to the slip-yoke (you can search for the mod; it gives all the details to do the job).

Pump in enough grease (40 to 50 pumps) until you feel the resistance; then a few more pumps. Things are smooth again.

_____

I have close to 1/4 to 1/3 rotation in the shaft before the rear tires turn; typical for the SD's.

 

Quarter turn? That's a lot ...

 

I agree, 1/4 turn is a lot. We did a pinion seal last weekend on a Dana 80 rear. There was about a quarter turn in the turn slack in the pinion untill we had the right amount of torque on the nut. Then there was just a small amount of turn in the pinion.

 

It depends where the turn starts. Don't forget the shaft turns 4 times what the axle does. I can easily see a quarter turn from an opposite direction start. ............Try it.

 

On an open-diff, with VERY worn spider gears, maybe

 

True, but we were only turning the pinion without the drive shaft off and there was very little turn to it.

 

I was thinking of under power shifting from reverse to drive and the OP said a little less than 1/4 turn also. ...........Try that.

 

I see what you are saying now. I think there is more turn the way you are describing it.

Oh, I fixed my last post, ment to type (drive shaft off).

 

Funny thing; I took it as driveshaft off.