Help! I just picked up my first Truck, a 1986 f150 supercab with an AOD(a project truck to say the least) and I have a problem with the drivetrain that i can not figure out. First off I have already changed out Transmission filter and put in some new fluid(truck has 155000 miles), my problem is a loud and annoying Klunk after I let off the gas pedal in the 25-45 mile an hour range. It does seem to shift a little hard also, after reading many of these threads I still dont know if my problem is in the U-joints or the Rear end or the transmission, or a combination of them. Any advice would be greatly appreciated.

 

Mine does this also. 2001 f150 supercrew 4x4 5.4L 95,000 mi.. Between 50-60 mph I hear a "clunk-clunk-clunk" when giving it gas, and a "clunk when letting off". I took it to a family owned shop(not the ford dealer). There was alot of slack in the rear end. So they sent the drivetrain off to a specialist to fix the yolk, and rebuilt the rear-end....when I got it back it ran fine, but 2-weeks later it started the "clunking" again...and now i dont know what to do errr..

 

Ive got a 2001 4x4 as well and it will only clunk when brakeing and accel, it done it at 15mls when new 3 dealers said it was normal, I even seen a bulliton on it, But have never gotten a straight answer on the cause, Ive read its the rear driveline splines, I wonder if the newer truck still klunk...my truck now has 76,000 mls with no problems..and the klunk has,nt gotten worse..

 

Spline grease job?

 

i dont think its normal. my last 01' f-150 screw had 200,000 miles on it and it never made a sound or klunk...but it was a 2x4...then it was totaled by some idiot..thought i had to add that little 2 cent in

 

Change the U-joints. It is quick, easy, and cheap.

Grim

 

im hoping to get a lift here soon so ill get some new u-joints

 

So I am going to replace all of the U-Joints and grease that spline joint and see what happens. Is there anything in the rear end housing that can or needs to be checked? Also it does appear that the transmission shifts late or when i lift of the gas a bit(for overdrive), I have read somewhere in here about the cable connecting from the throttle body to the transmission, is there an adjustment that needs to be done on that.

 

you need to go to ford and get a special grease they use for the yoke. it has teflonor something in it... the yoke is sticking and causing your clunking sensation... probably real noticeable when taking off from a dead stop... standard wheel bearing grease will last about a week in there... hope this helps..