guys,

my '02 4x4 supercrew has a driveline thunk/shudder that is driving me crazy...and not getting fixed by my local ford shop. when i pull up to a stop or even sometimes take off from a stop, there is a shudder/thunk that i can feel in the driveline. often times the thunk is felt immediately after i release the brakes at a stop. the truck has been back twice to the dealership to try and fix this problem, but so far no cigar. the first time the slip yoke splines were lubed and that worked for about a week. the second time the yoke and driveshaft were replaced and that worked for about 2 weeks. but of course the thunk/shudder is now back again. have any of you had this problem and been able to fix it? i'm getting frustrated by this and am now beginning to think ford has a design/engineering problem. any help would be appreciated...thanks...

 

I have a 1999, 2x4, and have the same thing happening to my truck. I have been looking around here to see if someone has been able to locate the problem. I changed out my rear diff. fluid, with Amsoil, and the modifier, but it still does it! Well, it stopped for about a week. Some guy said its in the springs. After he put helper springs on it stopped. Let me know if you find out any thing more!

 

i find it hard to believe it has anything at all to do with the diff or leaf springs...especially since my problem went away temporarily both times after they messed with the yoke and or driveshaft. guess i'll just have to take it back in and see what they try next...

 

Keep us posted Troy. I'm still VERY interested in hearing what they say on yours.

My dealership said they couldn't get it to 'reproduce the problem' and thus did nothing. I'm taking it to another FORD dealership here in Louisville sometime next week.

Also, I can't make up my mind if it's in the front end or the rear end. Probably rear but, I'm not sure.

Let me know...

RP

 

rock,

i was successful in getting it to thunk successively for the service manager. it isn't too hard on my truck since it does it at virtually every stop. somtimes worse than others.

i don't think i'll get the truck in this week but hopefully next.

 

TroyK, I also have a 02 supercrew 4x4. I don't know if yours is the same has mine but what mine does is if you let off the brake and coast for a second and give it some gas then it makes a loud clunk. I work for a dealer and compared my noise to several other new trucks and they all did the exact same thing but only the 4x4 would do it so mine is a normal noise. My truck doesn't make any noise under normal driving conditions but I can make this noise every time by letting off the brake giving a little gas, letting off the gas, and quickley giving it gas again. I'am not stomping on it, just light throttle. I hope this helps.

 

I'm the one who's "clunk" was fixed with the helper springs. I can't explain what it did to fix it, because I didn't get the helper springs to fix the clunk to begin with. Just an added bonus when I put them on.

Mine did the same thing. I'd come to a stop and go to give it gas and I'd get the clunk..... Would only do it after hitting the brakes, stopping, then hitting the gas again. Can't recall if it did it just slowing down, then giving it gas again......

One thing I did notice is that if I had any significant load in the bed, it did not clunk (before I got the helper springs). I loaded up about #1000 of bricks in the bed. Pretty much put the axle on the bump stops too!! (that's what prompted the helper spings in the first place..... not to increase the load capacity, but to keep it somewhat level with the same #1000 in the bed). Anyway, on the way home, I noticed that it didn't clunk anymore. Unloaded, went to pick up the other half of my brick order and I got the clunk on the way there. Loaded up, came home, no clunk. The next day, I purchased the helper springs and installed them. Took it for a test drive, and no clunk!!! It was empty too!! I've had them in for over a year now, and still no clunk. No wheel hop anymore on wet pavement either........ All because I could not stand having the truck sink to it's knees whenever it was loaded WITHIN it's payload capacity!!

Good Luck with your "Clunk". I'm not saying this will cure your's, but it did mine, and it sounds like they happen during the same set of circumstances.....

 

mitch,

did your helper springs change the ride height of your truck? just wondering as i'm thinking maybe the angle of the driveshaft changed and that eliminated your clunk.

also, putting on those helper springs might have changed the amount the rear axle is allowed to rotate fore/aft.

i've got about 400 lbs of sand bags in the garage...i think i'm gonna put those in the truck and go for a spin sometime soon and see what happens...


mxracer,

my trunk's thunking is "most noticeable" right when i take my foot off the brakes after having been stopped. sometimes it thunks so harshly that it feels as if someone tapped my rear bumper from behind. however, even though that is the most noticeable instance of the thunk, it also occurs at other times. sometimes i can actually feel a series of small thunks as i'm stopping, and then one good thunk when i take my foot of the brake pedal. other times i don't get any thunking while stopping...and nothing at the moment i take my foot off the brake pedal...but then as soon as i hit the gas...THUNK!!

troy

 

Troy your clunk sounds different than mine. My truck won't do it under normal driving conditions. Overload or helper springs won't add to the ride height unless you are adding a leaf to the existing springs, most overload springs add a second set of springs that are not used unless the truck is loaded. When you talk to your dealer ask them to call the Ford tech hotline if they can't fiqure out the problem. They might not like it but ocassionally the Hotline actually solves problems. The helper spring idea is a good one because the 4x4s have taller axle spacers which would cause the rear axle to rotate more under acceleration. I had a 4x4 truck a while back that had less than 1000 miles that made a wierd clunk type noise when you let off the gas I discovered the axle spacers were on backwards which caused the pinion angle to be off. Good Luck

 

Rockpick
If that dealer in Louisville doesn't help you, you might wnat to check with Earl Floyd Ford in Carrollton, KY. I have had my truck in the several times for different things and at least always had fair service.


My truck (97 F150 4. auto with 141K miles) does thunk some when letting off the gas then back on the gas. I figured it was due to driveline slop and the torque being released then reapplied. I have new u-joints, just need to put them in. What bothers me is when I come to a stop the truck feels fully stopped but a spilt second or so later you feel a delayed thunk. It's like the driveline was still turning and just caught up. I have also thought it might be the rear brake shoes grabbing and then releasing. One friend said it feels like I have a cracked drum and the show is catching on that and springing back. I'll figure it out one day or something will break and then I'll know.

 

No real change in ride height. Maybe 1/2" taller, at most, because of the extra tension I have them set to. No play in the driveshaft either.

The axle wrap theory is probably pretty good too. As I said, I don't have the wheel hop anymore either. Used to bounce all over the place on wet pavement.

 

MitchF150,

What brand helper springs did you use, and will they work with a 4x2? Did you also find that they made for a harder ride?

 

They are the LP-25's from Hellwig. I think the only requirement(s) are that the leaf spring needs to be 2.5" wide and the axle needs to be under the stock leaf springs.

They are "supposed" to be progressive overload springs, which means that they provide the stock ride when empty, but stiffen up as weight is added........ Well, that's probably true, if you set the tension to be very loose, but it'll rattle when going over bumps, and not really do that much for maintaining the ride height when loaded.

I found that when I set the tension to keep them from rattling, they did stiffen up the ride from the stock one. But, to me, it actually rides, handles and functions much better as a truck this way. I use mine for weekend chores and tow a 22' travel trailer that weighs #5000, fully loaded. Plus, I have to "compete" with my father and brother in law, who drive Dodge Rams....................... If my father ever saw how much the truck dropped when loaded up, he'd still be laughing! As it is, he actually said I'm impressed with how much you can actually put in that "little" thing.

Oh yeah, they sell the spings and the mounting hardware separately for some reason when you buy them online. I went to a local 4x4 shop and they sold it as one unit. Well, it was included in the price. I paid $150 + tax for mine.

 

I had the exact same probelm with my 99 ext. cab F150. The clunk occured either when I came to a stop or when I accelerated from a stop. I had it to the dealer multiple times. They greased the drive shaft yoke numerous times but this was a temporary fix. The clunk would return after a 100 miles. The last time the dealer replaced the entire driveshaft and yoke. The clunk went away for a longer period but returned after about 1000 miles. So far I have had no luck having the problem fixed.

One think I discovered on my own is that if I shift from drive to neutral at 20 mph right before I come to a stop the cluck disappears and the stop is very smooth. Those of you with the same clunking problem should try this. It would be interesting to see if the clunk is ellininated when in neutral. Unfortunately I'm not sure what this means but it seems the clunk might be caused by some type of strain or bind on the driveshaft while it is in drive. Once the truck is in neutral and no strain the clunk is gone. i wonder if this could be related to the diffrential gears?

The clunk was so bad and annoying that out of frustration I traded my truck for a 2001 Chevy Silverado. It sure is nice not having to put up with the clunk but unfortunately I have run into other problems with the Chevy. In my oppinion the quality of Ford is much better than GM. In the near future I am planning on going back to a Ford Super Crew. Hopefully by the time I am financialy ready, Ford will have corected the clunk.

 

Just wanted to let everyone know that I got rid of the clunk in my 98 f150 2wd. I found the grease leaking from the U joints. So I called my local Ford dealer and asked for the price $90.00 in parts OUCH!!!! anyways I called the local Pep Boys and found some heavy duty Hi Performance Ujoints for $30.00 bucks. Total install took about 2 hours.