I'm sure this has been asked before, but I couldn't seem to find it.

I have the 3.55LS diff in my 02 F150 4x4. If I change the ring & pinion to 4.56, do I also need to replace the LS diff? Or does that stay in there and just the ring & pinion get replaced?

I guess what I'm asking is if I change to 4.56, will it be 4.56LS when said and done, or do I need to get a specific LS just for the 4.56 gears?

 

All you change is the gears, not the carrier, so the limited slip will stay the same. It wouldn't be a bad idea to change the LS clutch discs at the same time when you are in there or better yet install a locker at the same time.

 

Thanks. I've decided to put in Detroit True-Tracs both front and rear at the same time.

Are Yukon Gears any good?

 

So a person who has a 97 F-150 5.4 4X4 with 3:55 gears can use the existing differentials when changing to 4:56 gears(8.8 in front and 9.75 in rear)?

 

Correct.

 

I love you guys................

 

yukons are strong but a little bit noisy because of how square they are. i have yukon in my rear end right now and it does howl a little but not enough to bother me.

once you get into 4.56 or larger numbers you end up with square gears which means the teeth are squared off due to the number of teeth needed on the ring gear to get that ratio. if they weren't squared off then you end up with a weak little point on each tooth.

can you put a true trac in the front diff? i'm just wondering because i'm not really sure.

 

Yes you can put the Tru-Trac in the front. It is one of the only limited slips you can put in the front without having the driveshaft turn all the time. I'm currently waiting for mine to be installed. I'll let you know how I like it when it gets done. Hope this helps.