I have my 2001 F150 XLT Supercrew 5.4 for two years now. This past weekend I changed the gear oil in the diff. using 75-140 per the tag on the diff. I also added the gear oil additive from my dealer per their instructions.

Here is where I found the problems. 1st when under the truck checking out the ujoints I found ATF all over the transfer case. I can't find where it is coming from. What places do I need to look?

2nd is now when I accelerate past 60mph and decelerate by just taking my foot off the gas I get a jerking which feels like its coming from the rear. I don't know what would be causing it.

I am a weekend warrior with a basic mechanic knowledge, so I am at a lost. Any help would be great.

 

For the rear end jerk remove both rear brake discs.
See if the emg. brake lining has come off it's shoes and is jamming up because it has no place to get out.
On the other, you just have to find it after cleaning everything off and checking again before it gets too wet.
Check the transfer case level and the main trans level for going low.
Good luck.

 

I also had that problem in my 2000. get the tranny and transfer case fluid swapped. that should take care of it. it did for mine and it was the exact same symptoms

 

You should remove the driveshaft and lubricate the slip yoke with the Ford-specified PTFE. Try this before anything else. It's cheap and easy and might fix this.

 

disregard this post - thought I was on another thread sorry

 

Check your u-joints while you are at it.