I took my truck into Performance Driveline bc the rear is making weird noises when I pull out from a dead stop and turn at the same time. The guy there said that 2004s were known to have crap rears in them. Its going to cost $750 to fix it ( according to him, it may not be a permanant fix) or $1100 for a used rear.....

Does anyone else have this problem or is it just bc my truck has 140k miles on it?

If it is a bad year, Will a rear from another year truck fit mine? Like an '05?

 

are you talking about the rear differential? or the bearings? when was the last time you changed the rear differential oil?

 

I also have a 04 xlt and it does the same thing. More so on turns from a stop. It feels like the limited slip is binding up or something

 

Ask him what is known to be crappy about them.

 

Ok. I've got an 04 F150 w 3.73 gear ratio / B6 rear diff. The inside of the diff looks like a bomb went off! What I found is that Ford used unsuitable materials to make the ring and pinion gear from the factory. It is not a recall due to it not being a safety issue, BUT.... of course they offer replacement parts kit which includes new ring and pinion gear, bearings and seals. About $500 in parts. Google F150 rear differential problems and you will soon find out what I am talking about. Currently deciding on what to do to mine, replace w used or rebuild. All about the same in the end as far as $$$ depending on if you find a deal at a parts yard. Let me know what you find. Pull the cover and see how it looks. Good luck!

 

Oh BTW, Most 04-05 are affected, if you go used look for 06 thru 08. Of course the yards must know this due to the price difference.

 

Change the lube in the rear and throw in some friction modifier...done

 

You know this from experience? Youve had this problem in your truck?

Performance Driveline opened it up and changed the lube..I dont think he added any friction modifier. I'll try it for a temp fix but I dont know how the rears going to hold out. I think I'm going to shop for an 06-08 rear.

 

Thats exactly how mine feels.

 

I had the same problem. i have an 04 with the limited ship and i had my rearend making some grinding and funny noises on slow turns and from a stop. i went and drained the fluid. no materials or anything in it because they ran it through a strainer. when they filled it back up they put in 2 bottles of friction modifier then filled the rest up with synthetic diff fluid. made all the difference in the world. saw my mileage go up about a half MPG with the modifier and synthetic fluids.