When I accelerate from a dead stop, I get a slip sensation, or thump/clunk in what seams the back rear left. Very annoying

They have greased the slip yoke - did not help. So, they are replacing my entire drive shaft. Its on backorder I guess, been waiting for 3 weeks now. Will post an update when I have it.

 

I have the same problem. It is only periodically, so of course it wouldn't do it for the mechanic. I've found that it does it with moderate acceleration from a stop or when accelerating from a 10-15 mph turn.

 

Have the same issue.

 

What should we do?

 

Axle trouble? If the noise comes from the left I doubt it'd be the drive shaft..... If it happens when you step on it it probaly means something cannot take the pressure so it slips and makes the clunk. Last time I seen a clunk problem was when some spider gears were messed up.

 

There was a thread about having the clutch packs replaced to cure this problem.

 

I have the same problem with the "clunk" on acceleration. I took the service rep and a tech for a ride to duplicate the problem (they couldn't feel it on their own). Thankfully, I was able to make it happen and they said they need to replace the clutch pack in the rear differential. I dropped it off this morning to have the clutch pack replaced along with other minor warranty stuff. I hope this fixes the problem.


2004 screw 4X4 5.4

 

I just found the TSB notice for this issue on the internet. It was released in June. Jesus, dont these techs read these things?

They are giving me a drive shaft and you clutch packs..... so which is the real fix????

 

They never mentioned anything about replacing my drive shaft. To add to the confusion, I read somewhere in this group another fix for the problem was to lubricated the splines on the drive shaft where it enters the transfer case (4x4)(there is even a TSB for that). I mentioned this to the tech, and although he understood what I was talking about, he stuck with the first theory which was to replace the clutch pack. I still haven’t pick up my truck yet from the shop.

 

I will let them do drive shaft, but if that dont work, i will request clutch packs i guess.

Gotta love Ford Svc.

 

What Axles do you guy's have?? Are they Limited Slip? Must be if they are talking clutch pacs in the rear..

I still don't understand how you would feel a slipping unless you were turning the rubber and the other tire grabbed.

 

I have the limited slip differential. It's funny you bring up the fact that you don’t understand how it would slip unless the vehicle is turning (clutch pack issue). It's more pronounced when accelerating straight, hence my pointing out the TSB on the splines of the driveshaft being the problem (poor lubrication and sticking under load). However, the tech asked me to make a sharp turn then accelerate. The clunk was faint, but noticeable. The tech then decided that the clutch pack was the problem.

I was expecting to have my truck back tonight, but the dealership did not finish it, so my truck has to stay the night in a strange place all alone. Should be able to pick it up tomorrow.

If the clutch pack being replaced doesn’t fix the problem, I’m going to lubricate the splines on the drive shaft myself.

 

Please let us know if it fixes the problem!

 

My dad had the same problem. His dealer said there was a problem for trucks manufactured in the Feb - March timeframe. His rear wheel bearings were too tight and there weas a problem with his limited slip differential...They ended up replacing all of it.

 

Ford Fan, I guess I didn't phrase that right. By turning the rubber I meant spinning the tires(burning rubber) and having only one tire spinning then having the clutches in the rear grabbing late to engage the other tire. That might give you a twisting feeling. I can't see where greasing the DS spine would help..

The reason I asked what axles you guys have is because Fords Limited slip(Traction Lok) axles have always had a clunk in them. Even back in the 60's I can remember the old man having the dealership rebuild one in a 66' Fairlane. The 68 LTD and my 69 Mach I did it. I had a 72 Ranchero with an open rear and it was solid and tight. I had 84 F250 with an open rear and it was tight. The 88' Bronco I have now bangs and clunks(LS) away when you shift it between forward and reverse and I just spent 1600 bucks having it rebuilt at Ford dealership.