was wondering what type of diff i can put in rera end to upgrade it instead of the factory one

 

Not understanding. Do you mean gears? Or the punpkin? Your wallet is really the limit. You could put a dana 70 in there if you had the know how.

My understanding is the diff is already pretty strong so you might just want gears.

Tell us more about what you want to do and/or issue you are having. Also what year, motor, 4x4/4x2, and axle ratio do you have now.

 

Well its just factory so I want to upgrade it. My truch is a 06 f150 fx4. I just want to be able to make it a bit stronger. I'm new to upograding my truck

 

i've always worried about my rear axle and how hard i am on it especially with my big tires but i took it apart the other day to change a wheel seal and i'd have to say im not worried about the axle shafts at all. the shafts were at least 1.5in.s in diameter at the thick part. hell that's not much smaller than some 2.5 ton rockwell axles that i took apart not too long ago.

id say the ring and pinion gears would give before the shafts.

 

If you have a FX4, you have a 5.4 engine, right? If so, you have a 9.75" rear and it's very strong to begin with. I do not see any need to upgrade it.

 

I believe that the 9.75" diff is typically rated around 4000 lbs, but the folks claiming to have engineering data put it at 4500 lbs. I think the main failure mode is the tubes breaking at the pumpkin when overloaded. I haven't heard many stories of 9.75" diffs failing.

 

Find something else to upgrade if you want to spend some money.
The rear is VERY strong in your truck!!

 

my transfer case is grinding and squealing was wondering what cause could be and if i need a new one or if its something else