You know that thud that occurs when first taking off from stop, well greasing the slip yoke worked to fix it. I appreciate the help I got from this forum. The Ford dealership looked at me like I was crazy when I told them what I thought it was. They wanted to pull my tranny or replace my rear springs. I said HELL NO!!! It took me about 30 minutes and five bucks for the grease. This is a huge releif. Thanks for the help.

 

Good job of diagnosing the problem.

 

I have a 2002 Powerstroke with the same problem. How exactly do you grease the yoke. Is the slip yoke located at the rear of the drive shaft.

 

If you have the two peice driveshaft, its the rear section that goes to the axle. You need to remove the u bolt clamps from the rearend and the rubber dust boot and the shaft will slide out of the yoke. Grease the slines and/or the inside of the yoke. I found it easier to remove the whole rear section of the driveshaft, grease it and then reinstall it as one peice. Make sure you mark everything, its balanced and need to go in the exact same position. My instruction may not be very good so this site I found will help illustrate. http://www.eurekaboy.com/f250/slipjoint.htm

 

Exactly, well for starters look at the FAQ section for a post, with photos, on the subject. It is not hard, put the truck in park, set the brake CHOCK THE WHEELS. Match mark the joint behind the female section of the slip joint to the drive shaft. Match mark the driveshaft to the differential flange. Put some penetrating oil on the four bolts holding the driveshaft to the differential flange. Take the factory boot clamp off the end of the driveshaft, male end of the spline connection. No need to remove the boot clamp toward the carrier bearing end. If you work with it you can reuse the factory clamp, I did. Driveshaft, it will probably be tight so take three bolts out, leave the fourth finger tight. If the driveshaft doesn't fall loose bump it toward the front with a rubber hammer. It will ride up on the splines and fall loose on the last bolt you left in. This keeps it from knocking your teeth out if you are laying under it. Pull the male driveshaft end out of the splines about 3" and note that it's position. I matchmarked it again. Pull it out and put some wheel bearing grease or EP1 grease up into the female end, deep, get some on all the splines. Put some on the male end and put the male end into the female end. It will probably air lock and at first not want to go fully back into the female end. Hold pressure on it and it will force the trapped air from the female end, you will see it burp grease. Push it all the way on, bolt up the differential bolts, hook up the boot clamp and you are done. Things to watch out for. If you don't CHOCK THE WHEELS the truck may roll on you, or on top of you. At the very least it will make putting it back in the spline position you found it in difficult if the wheels roll and the differential rotates. The splines must go back in the same position they came out, there is a flat area in the spline cut, it is not like any gear will do. Just watch for it and it will be no problem. One more thing, if the truck is a 4X4 no need to put it on blocks or ramps. If it is a 4X2 put the rear wheels up about 4" CHOCK THE FRONT WHEELS. Hope this helps.

 

Mine isn't so much when you put it in gear, it is when you take off from a stop, like at a stop light, etc.. I was thinking it was the u-joint in the rear drive shaft. I pull a trailer all day and plow snow in the winter. My truck only has 20,000 miles on it. What do you think.

 

Just wanted to thank bcmmdl for the link. That is an excellent photo walk through of what to do...Again thanks.

 

Tbird, that is the thud being written about. Try lubricating the driveshaft per the instructions above and if it is your problem it will go away. It won't hurt and only takes about 30-45 minutes. Mine did the same agravating thud from a standing start, worse was standing start up hill. Now it is smooth and you don't anticipate that thump 2 seconds after you get on the power.

Regards

 

Thanks for the link. My 01 F250 4x4, CC makes the thud noise also. Kinda been worrying me lately. Not the first thing to be wrong on the truck. So it goes.

So greasing the splines makes the noise go away, but what is actually making the noise? I mean is it the male splines knocking into the female splines that makes the thud, or what? Just curious.

Oh, so this seems like it's going to be a maintenance item. What would be a good greasing interval. When it starts thudding again?

Thanks,
-Shawn

 

Shawn, there is not enough clearance in the splines radially to make the "thud". If there were that much clearance a little grease would not stop it. IMO when the driveshaft torques up in the flex center of the carrier bearing it moves on the axis of the driveshaft. The torque of the wheels rotates the body that the carrier bearing is attach to forward, makes the frame squat down slightly. That produces a difference in total demension between the diferential and the carrier bearing that must be made up or something will break. That is why a spline slip connection is there. If it can't slip easy on axis it winds up until it produses enough pressure then moves axially and you get the thud. I don't know how long between lubes it will go. That would depend on a lot of things. When mine starts to thump again I will just grease it again. It is not a hard thing to do anyway. Also, IMO, if you let this symptom, the thud, go it will lead to a premature carrier bearing failure.

Regards

 

Cool, thanks for the quick response. So its actually fore and aft movement (along the axis) of the shafts because the slip joint isn't slipping. Got it. Didn't really know what the slip joint was for (until now).

Guess I'll be spending a little time under the truck later this week. Seems easy enough, and I will get to use my fancy spline/bearing grease for my Beemer.

Thanks again,
-Shawn

 

Has anyone had a thud noise more from the front end. This happens soon after start and without any vehicle movement. Any ideas? Its a 2002 4 door 4 wheel drive.

Thanks

Mark

 

Fordguy, you wrote "soon after start and without any vehicle movement". At first the "without any movement" part confused me. Seems like you meant it literally, no movement. One thing that I know of will give a thump in the front end, soon after starting, no movement. I startles the heck out of me every time. I always think that I have backed over the garbage cans. When this happens to me it is because the last time I shut down the motor I left the climate control in the AC position. Powerstrokes have a vacuum pump. It takes that pump a few moments after starting to produce vacuum. When it comes on it will slam a damper door inside the dash ducting closed. If this is the thud you are hearing just ignore it or turn your AC to the off position when you shut down.

 

Its a thud that you feel through the floor. It sounds like it is comming from outside the vehicle. I will try what you are saying just to make sure. Sometimes I will get the same thud but it will come from the rear of the bed??? My truck is possesed. When the door closes does it sound pretty violent?

Thanks for the help

Mark

 

Hmm, it's the no movement thing that makes it seem like the AC door. I never heard mine sound like it came from the rear. Mine makes a pretty loud thuuuuuummp type sound, like about a 2 lb book dropped flat on the floor from 3 feet would make. Does not do it when I leave the AC control on MAX AC then start. Try leaving the truck overnight with the AC in the off position, start it and if the thump goes away that is it.