'99 XLT - rear "clunk" - first post - HELP!?

[ChuckRanger]

Hi guys - I'm hoping this forum is going to help me out a lot over the next few years!... I got this truck last month for my two boys. - first one gets licensed in January...

I paid too much and have already taken care of: front rotors and pads, rear brake rebuild, rear axle seals, tranny drain/fill, radiator flush/fill, thermostat, differential drain/fill, one rear brake line... (plus I had to sand and buff for 4 days to remove super glue from EVERYwhere!) But, we like the truck and this site has already helped - I know I'll be using it for the stuff below...

It appears to need a new hub-bearing assembly on right front, lower (and maybe upper) ball joints and THIS semi-nagging problem:

There is a "clunk" stopping and going at any time... I've read a lot here about "greasing the slip-yoke". I don't think that's it on mine. It appears that it does not take much torque to tweak the rear axle on the frame a bit... whether just putting it in gear or using the brakes, I can watch below and the differential moves just slightly in the opposite direction of the frame.

A suspension mechanic agrees. His guess would be to put an additional or upgraded leaf springs on it...

Is this a common problem? What is the best (and easiest) fix? This truck is just for road use and in the snow a lot. I want it to work right and be safe but I'm not looking to spend a lot of money (or time) if it can be avoided!

Thoughts?
Thanks!

 

[Jspafford]

Easiest way to fix it is grease the slip yoke. Most likely the problem will go away for you like it did for the other million or so people who had the same problem.

If not, then try the suspension. The axle will twist when put into gear, how much depends on spring condition.

 

[JohnnyO]

Is this a common problem? What is the best (and easiest) fix?

I had that problem on both my 99 and 02 Rangers. Both were on warranty so it didn't cost me anything, but the fix was a new aluminum driveshaft from Ford to replace the original steel driveshaft. There is a TSB on it. A new one probably won't be cheap but there should be a few in the junkyards by now.

 

[4x4junkie]

Grease the slipyoke. Then go from there if that doesn't fix it. (99% chance its the slipyoke)

Slather the spline liberally both inside & out with a molybdenum CV joint grease.

 

[ChuckRanger]

Got it guys. I'll try that and see what happens....

Thanks for the help.

Now it's slipping in reverse!!... Ahhhhh... that'll be another thread.