Ok i have a 2000 f150 132k 5.4L 4x4. I had to get a junkyard rear driveshaft in the fall.. snap ring on ujoint fell out at 80Mph. witch in return f'd my driveshaft. So got one put in on. seem ok for a little. Than vibration replaced both ujoints better still there slighty. Ok Pulled front driveshaft (junkyard also) ujoints look bad left the driveshaft out. Still have the same problem. Around 40MPH and 50 to 60MPH Any ideas?

I'm thinking 2 things right now.

1. Unbalanced rear driveshaft
2. rear diff. The fluid was a little low but not bad.

And this all goes on top of me leaking trans fluid.. Not sure if pan or not. but its comming from pan area.

 

take it to a driveline shop and see if its balanced. check to make sure there is nothing stuck on it, like mud or whatever.

i dont think diff fluid would make it vibrate.

check pan bolts to see if they are loose.

 

Pretty much my next stop. Any idea on cost?

Didn't think it would.. Maybe its going? I want new one's but no cash yet. 4.10's lockers.

I replaced the pan gasket. Bout ready to take back off and reuse old one.

And on top of all this. my ultra guage started telling me i'm only getting 8MPG at 44MPH WTF? just started when i took the front driveshaft out

 

I don't know how much they would charge to balance it.

The stock gasket is the best one there is, it's much better than any aftermarket gasket.

 

I'm going to call around tomorrow.

Yea i was told.. going to redrop the pan and use the stock one.

I'm now thinking the vibration could be from the tailshaft bearing. I don't know how to check that though.

 

disconnect the driveshaft and see if there is any play in it.

 

Well when i put the front shaft back in a test it. i'm going to pull the rear off and drive it..

And weird MPG thing. Last two day my 4x4 and 4lo lights have been on ( how often do you have 2lo Without man hubs?) but i was getting 7.88MPG at 44MPH today lights finally shut off ( ongoing problem with the lights sticking on for some reason) and i'm Getting 24MPG at 44MPH. Remind you i have had the front shaft out for two days now.

 

i would hand calculate your mpg instead of relying on that thing.

 

I'm only relying on it now because i had had it for allmost a year and pretty close.

 

oh, well i wonder what the whole tank will come out to in the end. unless you filled up between those 2 readings.

 

yea just put 40 in it. It could have messed up. Allways possible. According to it i'm still getting 12.9 AVG

 

Did the drive shaft come undone and get snapped? could have bent your tail shaft if it did..

 

Yes and no.. The sanp ring came out. ujoint fell but didnt hit the ground. So it is possible and i am leaning towards that also

Thing is the vibration is hit as miss. sometimes you fell it other time not.

 

Back to the trans pan.. I appers to not be leaking anymore.. Maybe it needed time to set?

 

Are any of the bolts loose on the pan?