I did some research and i know on 1997 there was a drive shaft spline issue that there would be a grunt or shudder from a standstill when accelerating (a tsb does exist). Now i have a 99 f150 5.4L 4x4 that is having the exact same issue and infact goes away after a few miles once fully warmed up (also does it when there is a load in 4th gear, low rpm when torque is peak. Supposedly the fix is teflon grease but i dont have the time to poke around to see what could possibly be the cause.

what do you say, drive shaft splines?

also does anyone have a tutorial how to do it?

im convinced its not my transmission, for 200 thousand miles, this truck shifts and runs great!

 

Bump

 

All I have ever done is pull the drive shaft and grease the slipyoke - inside and outside. Check for wear edges on the slipyoke and output shaft. Other than that there isn't much to it. Be sure to reference mark the shaft at the ends (make sure it goes in exactly in the same pos. it was in to avoid vibration).

 

When pulling the output shaft out the back of the transfer case, im assuming all my fluid will back out?

 

Some fluid might come out, not much - just check the fluid level in the T-case afterwards.