Help!!! Differential Questions: Gears, Lockers, and Diff covers Front and Rear!

[ISFast]

Ok this is going to get long and I'm truly sorry, but need some help. I'm pretty new to the whole Differential part of turning wrenches. I know just enough to get myself in trouble. So when because its only a matter of time before I ask something stupid because i'm ignorant.

So.... With that said. Tuesday I'm going to my differential/axle guy. My old roommate who I trust as gone to him for years and years. I'm sure I'll find out a bunch more about what my needs/wants are, but I can't freaking stand it just thinking about it and not knowing. Plus want to make sure I'm on the same page if I can be.

Few things needing answered:
1. Gears what ratio?
2. Differential covers?
3. Lockers?

Back ground of the truck:

Right now I'm running 35s but 37's are coming. There is glass for the front fenders showing up as well. So other that TRR to run out my old 35s it will be 37s... maybe bigger down the road... from here on out.

1:Gears
I'm thinking that 4.88s would be great but have thought about 5.13s.

Questions about the gears
1. Will 5.13s fit both front and rear?

2. Any downside to 5.13s because it does something that isn't as good as 4.88s?

3. Any company of gears you recommend and why?

4. Would like quite gears but my tires are so loud not that big of an issues. My main thing is the really good/tough gears. Which company?



2: Differential covers
I'm wanting to do a Mag Hytec cover for the rear because it will be easier to mess with changing/checking fluids and how they look.

Questions about diff covers
1. Can I get a Mag Hytec cover for the front?

2. Does the stock front cover have a drain plug already?

3. Any other covers you would consider?


3: Lockers
I know the locker in the rear works pretty well, but I have issues with it kicking out because I usually dont run ORM. I like the ARB style air locker and good excuse to put air on the truck

Questions about Lockers
1. Can I get an ARB air locker for both front and rear?

2. Can I get an ARB locker with the gears changed out to 4.88 or 5.13?

3. Any down side to running an ARB locker because maybe its not rated for high speed?





Other questions I have about things related

1. Is the front end a 8.8, 31 spline, reverse diff?
1a. Is the rear a 9.75, 31 spline?

2. Any issues on getting 5.13s to fit or would it be a hassle to mess with so stay to 4.88s.

3. I know guys with the torsen front ends are having problems eating the CVs and IWEs up faster than us 2010 or 2011 guys. I'm hoping with an ARB locker up front that this will help keep torque all the way across the axle rather than all on one side or the other. Also, When I would have to switch on a ARB locker I know its probably going to be low speed and if I need to get crazy I know theres a higher chance to grenade the front end or I can unlock it.

4. The ARB locker will make it easier for me to run with out ORM and locked up the rear.



Thanks again! I know its long and I've been freaking dreaming about trucks and gears for the last 3-4 nights. I can't make it stop so I'm hoping to get some help.

I'll post up my ratios with RPMS and speeds that I posted in 4.56? gear thread and then add 5.13s. I know some of if not all my questions will be answered Tuesday but really would like the input from some guys who know more than me.


I'm sure I'll add more so I'll time stamp it and add it.


Gear ratios: RICHMOND Street Performance Calculator


40" tires for all gears:

5.13, 70 mph, 40" tires, in 6th gear 0.69 ration makes the motor turn 2081 rpms

4.88, 70 mph, 40" tires, in 6th gear 0.69 ration makes the motor turn 1980 rpms

4.56, 70 mph, 40" tires, in 6th gear 0.69 ration makes the motor turn 1850 rpms

4.10, 70 mph, 40" tires, in 6th gear 0.69 ration makes the motor turn 1663 rpms



37" tires for all gears:

5.13, 70 mph, 37" tires, in 6th gear 0.69 ration makes the motor turn 2250 rpms

4.88, 70 mph, 37" tires, in 6th gear 0.69 ration makes the motor turn 2140 rpms

4.56, 70 mph, 37" tires, in 6th gear 0.69 ration makes the motor turn 2000 rpms

4.10, 70 mph, 37" tires, in 6th gear 0.69 ration makes the motor turn 1798 rpms



35" tires for all gears:

5.13, 70 mph, 35" tires, in 6th gear 0.69 ration makes the motor turn 2379 rpms

4.88, 70 mph, 35" tires, in 6th gear 0.69 ration makes the motor turn 2263 rpms

4.56, 70 mph, 35" tires, in 6th gear 0.69 ration makes the motor turn 2114 rpms

4.10, 70 mph, 35" tires, in 6th gear 0.69 ration makes the motor turn 1901 rpms




EDIT: 2/21/2013


Chart for 5.13 gears in each gear (1-6) to Redline~

35s:
1 gear runs 29 MPH @ 5956 RPMS
2 gear runs 52 MPH @ 5992 RPMS
3 gear runs 80 MPH @ 5989 RPMS
4 gear runs 106 MPH @ 5951 RPMS
5 gear runs 141 MPH @ 5972 RPMS
6 gear runs 176 MPH @ 5981 RPMS

37s:
1 gear runs 31 MPH @ 6022 RPMS
2 gear runs 55 MPH @ 5996 RPMS
3 gear runs 84 MPH @ 5948 RPMS
4 gear runs 112 MPH @ 5948 RPMS
5 gear runs 149 MPH @ 5970 RPMS
6 gear runs 186 MPH @ 5979 RPMS

 

[Wilson]

why

 

[pirate air]

I'd go with 4.88s. I think 5.13s would be over kill unless you're planning on a 40" tire. You also have to remember 5.13 would be that much harder on the cv shafts and iwe's because you've multiplied the torque that much more. The pinion gear also loses more strength because its physically losing more size.

I would look at yukon brand gears if installing myself but in your case i would see what the installer prefers to use. If you choose a gear other than what the installer wants to use and it whines, you might have trouble getting him to fix it. Some gear brands are inherently noisier than others.

Mag tec cover for the rear is a good choice but unfortunately there's no option for a front cover because you have very limited room in the front for anything more than the factory stamp steel cover. A regular aftermarket 8.8 cover will bolt to the front diff housing but good luck getting the assembly to fit back into the truck.

Yes 31 spline reverse cut.

I don't know what ARB has for the Raptor. I've installed and worked on their lockers but always on jeeps. I would imagine high speed won't be an issue. Even a locker applying continues torque to the iwe is still going to be pretty hard on it. Most importantly will be how hard you push them/how you drive. Again, going larger with tires and larger in ratio will just work the iwe that much harder.

 

[ISFast]

Thanks Pirate! That answers most of my questions. I figured the 5.13s maybe a bad idea due to the pinion gear is now smaller/less material making it weaker.

Do you know if the factory front diff has a drain plug?

 

[Wilson]

now I get it bigger tires. so 4:10 is low 4:88 is lower?

 

[ISFast]

why

Why get a raptor? Why use e-30? Why run a tuner? Why run exhaust, intake, different tires, etc?

Why not? I never plan on going faster than 120-130 and so I feel like i'm leaving some of the gearing on the table. As for the rest of it. I'm going to already be in the axle housings why not just go ahead and do it while i'm there. And if its only a few bucks more for the ARB to be put in now rather than cost a ton more later.

Its really more of a "want" than a "need" same with almost everything about a raptor. I don't need any of it but damn nice to have it and damn glad I can afford it.

There maybe a point in time when I may not have the opportunity to do this so why wait life is short and mods take time.

 

[pirate air]

Negative on the drain plug. Fill plug only.

 

[ISFast]

now I get it bigger tires. so 4:10 is low 4:88 is lower?

IT is a ratio of how many times the drive shaft has to turn to one revolution of the wheel.

So 4.10 gears:
The Drive shaft will turn 4.10 times to every 1 turn of the axle shafts "tires"

---------- Post added at 09:23 PM ---------- Previous post was at 09:22 PM ----------

Negative on the drain plug. Fill plug only.

Dang! That was my main reason for the different cover... same for the rear.

Thanks again

 

[pirate air]

IT is a ratio of how many times the drive shaft has to turn to one revolution of the wheel.

So 4.10 gears:
The Drive shaft will turn 4.10 times to every 1 turn of the axle shafts "tires"

---------- Post added at 09:23 PM ---------- Previous post was at 09:22 PM ----------



Dang! That was my main reason for the different cover... same for the rear.

Thanks again

No problem.

Yeah it makes it a pita servicing the front diff, but iirc the service interval is 100k so guess ford doesn't expect you to mess with the fluid that often.

 

[ISFast]

No problem.

Yeah it makes it a pita servicing the front diff, but iirc the service interval is 100k so guess ford doesn't expect you to mess with the fluid that often.

True and probably won't change it very often. Just never know when you might swamp the axles and then your cussing trying to change the fluid haha

---------- Post added at 09:30 PM ---------- Previous post was at 09:29 PM ----------

Hey Greg.... Got those beefed up IWEs yet?