Sterling 10.5 Questions

[wt91]

Looking at buying gears and install kit for my 2011 Sterling 10.5 with factory elocker. Wanting 5.38 gears. Called and spoke to nitro gear, the tech wasn't much help. Reached out to a few companies via email and either got no responses or no answers. Read through this thread and doesn't seem like there was a final consensus either.

I know the 10.25 gears can go into the 2010 and down 10.5 housings with the correct bearings. My question is are there any differences from 2011+ to 2010- other than the 37 spline pinion yoke? If I got a 5.38 gearset for a 2010, with a 31 spline pinion, and a new yoke to match the new pinion, would I be good? Are there differences in the bearing pockets/etc that would prevent this setup?

Does anybody actually make 5.38 10.5" gears for these, or are they all just 10.25 gearsets sold as 10.5 gears? Nitro SKU F10.5-538L-NG says good for 1993-2022 model year 10.5 axles...and in 1993 it would've been a 10.25. So I'm assuming they're all just 10.25s?

Would appreciate hearing from anyone who's played around with these axles or knows the answers. Dont wanna just throw money around until I end up with the correct mismatch of parts.

 

[Wfoyota]

zero help here but my first call would be to east coast gear supply to ask.

 

[gozuki]

Long story short, you need the 99-2010 housing. The 2011+ housing will not accept earlier style gears, and there isn't anyone making 2011+ sterling 10.5 gears aftermarket AFAIK.

 

['84 Bronco II]

Long story short, you need the 99-2010 housing. The 2011+ housing will not accept earlier style gears, and there isn't anyone making 2011+ sterling 10.5 gears aftermarket AFAIK.

There are 37 spline aftermarket gear sets up to 4.88, but no deeper last I checked.

All of the 31 spline aftermarket gear sets are 10.25" instead of 10.5" because the aftermarket companies suck

My understanding is that you can't put a 31 spline gear set in an '11+ housing, but I haven't seen anything concrete posted about that. If I recall correctly, the last time I looked at Rock Auto, it looked like the outer pinion bearing should interchange

 

[RunningProblem]

Why wouldn’t you be good? If the only differences are a 37 spline pinion, and bigger axle shafts you should be fine. You can get new 2011 bearings if you want, and just make sure everything in the 2010 yoke matches up except for the spline count. Make a write up and detail it. Return parts so it doesn’t cost a bunch of money.

 

[arse_sidewards]

All of the 31 spline aftermarket gear sets are 10.25" instead of 10.5" because the aftermarket companies suck

Does that matter? IIRC the pinion was the change that mattered.

My understanding is that you can't put a 31 spline gear set in an '11+ housing, but I haven't seen anything concrete posted about that. If I recall correctly, the last time I looked at Rock Auto, it looked like the outer pinion bearing should interchange

That's my understanding.

Long story short, you need the 99-2010 housing. The 2011+ housing will not accept earlier style gears, and there isn't anyone making 2011+ sterling 10.5 gears aftermarket AFAIK.

Why? What's the incompatible part?

Why wouldn’t you be good? If the only differences are a 37 spline pinion, and bigger axle shafts you should be fine. You can get new 2011 bearings if you want, and just make sure everything in the 2010 yoke matches up except for the spline count. Make a write up and detail it. Return parts so it doesn’t cost a bunch of money.

x2

 

[wt91]

Called ECGS, talked to a very helpful tech guy. He said the 2011+ axles can only be used with 2011+ gear sets. He said he wasn't exactly sure of the difference, but it was something regarding the length of the pinion, the spline difference, and the inner bearing. Says it's something their engineering department has been looking at due to these axles becoming more popular/commonplace in junkyards, etc.

Outer pinion bearing and carrier bearings are the same PN's. At work, else I'd pull the PN off the inner bearing that's on the pinion I took out of the 2011 axle.

Anybody got a 10.25 gear set (the long-spline version that would swap into a 10.5) laying around to take some pinion measurements?

All told I'm $300 into this axle, if I need to grab a $150 JY 2010 down axle I'm not gonna cry about it. I'll keep everything that can be saved as a spare part and scrap the 11+ housing, if it comes to that.

Edit: In fact, found a 2008 10.5 complete with brakes about 30 minutes from my place for $50. Gonna grab it tomorrow AM and I'll compare the gearsets myself when I strip it down and I'll post the results.

 

['84 Bronco II]

Does that matter? IIRC the pinion was the change that mattered.

Yes it does. Increasing the ring gear diameter with the same diameter carrier improves gear strength in 3 ways. The most obvious is that the larger ring increases the radius of the center of the pattern from the axis of rotation, but it also increases the size of the pinion head for any given ratio as well as the gear face width. 1/4" might not seem like much, but in the Super 60 applications, I have seen a 16% strength increase published (9.75" vs 10"), so I assume it would be in that same ball park for the sterling. I firmly believe the aftermarket ratios being 10.25" is a large part of why the 14 bolt has a reputation for being stronger. Ford never used a 10.25" in anything that had more than 420 Ft-Lbs. from the factory and felt the need to go 10.5"in 1999 when the Powerstroke came out with 500 Ft-Lbs. They upgraded to 37 spline pinions in 2011 when Powerstrokes had 800 Ft-Lbs. and still offer the Sterling in F250s with 1,000+ Ft-Lbs., so I have to believe that there are real strength increases with the changes they made to the Sterlings over the years.

but it was something regarding the length of the pinion, the spline difference, and the inner bearing

The short vs long pinion splines was a change that was made around '91-'92 and really only affects which pinion yoke you can use. That would make sense if it is the inner bearing that is different and the pinion shaft is physically larger at the head in addition to the larger 37 spline at the yoke.

 

[arse_sidewards]

Yes it does. Increasing the ring gear diameter with the same diameter carrier improves gear strength in 3 ways.

I know. But the pinion was the most common thing to break (not a lot of people using these in crawlers but look at what the diesel truck pullers were breaking) by a mile until the 37spl in 2011. So while it's an improvement on paper and probably matters for warranty rate I don't think it really matters for us because until you hit 37spl the weak link is the same.

The most obvious is that the larger ring increases the radius of the center of the pattern from the axis of rotation, but it also increases the size of the pinion head for any given ratio as well as the gear face width. 1/4" might not seem like much, but in the Super 60 applications, I have seen a 16% strength increase published (9.75" vs 10"), so I assume it would be in that same ball park for the sterling. I firmly believe the aftermarket ratios being 10.25" is a large part of why the 14 bolt has a reputation for being stronger. Ford never used a 10.25" in anything that had more than 420 Ft-Lbs. from the factory and felt the need to go 10.5"in 1999 when the Powerstroke came out with 500 Ft-Lbs. They upgraded to 37 spline pinions in 2011 when Powerstrokes had 800 Ft-Lbs. and still offer the Sterling in F250s with 1,000+ Ft-Lbs., so I have to believe that there are real strength increases with the changes they made to the Sterlings over the years.

You're giving the GM way too much credit and giving "it was in the junkyard for the right price in 1999" way too little credit.

 

['84 Bronco II]

I know. But the pinion was the most common thing to break (not a lot of people using these in crawlers but look at what the diesel truck pullers were breaking) by a mile until the 37spl in 2011. So while it's an improvement on paper and probably matters for warranty rate I don't think it really matters for us because until you hit 37spl the weak link is the same.



You're giving the GM way too much credit and giving "it was in the junkyard for the right price in 1999" way too little credit.

Like it or not, a 14 bolt gear set is more than just trivially stronger than a 10.25" gear set, but my point is that the gap with a true 10.5 gear set would be smaller. If the 37 spline pinions do indeed use a larger inner bearing (and presumably have a larger diameter under the head), that would go a long way to reducing gear deflection and eating up the advantage of the 3rd pinion bearing in a 14 Bolt.

EDIT: I also just read an old post on Pirate claiming that the '11+ axles also have a slightly larger 10.6"ring gear, but I also have no idea whether that is actually true.

 

[wt91]

Like it or not, a 14 bolt gear set is more than just trivially stronger than a 10.25" gear set, but my point is that the gap with a true 10.5 gear set would be smaller. If the 37 spline pinions do indeed use a larger inner bearing (and presumably have a larger diameter under the head), that would go a long way to reducing gear deflection and eating up the advantage of the 3rd pinion bearing in a 14 Bolt.

Not the most scientific thing, but if Motive Gear's website pictures can be trusted the 37 spline pinion looks massive right under the head vs the 10.25 pinion. When I pick up the 2008 axle this weekend I will post up measurements of pinions and bearing pockets to give a definitive answer and reasoning for any others in the future.

4.56 set for 11+ 10.5

4.56 for 2006, 10.25

 

['84 Bronco II]

When I pick up the 2008 axle this weekend I will post up measurements of pinions and bearing pockets to give a definitive answer and reasoning for any others in the future.

Please do, I have been trying to get this info for a long time

It seems silly now that 37 spline Sterlings have been in production for 13 years, you still can't get deeper than 4.88 gears for them

 

[gozuki]

It is the earlier pinion that won't work in the 11+ housing. I went down this road with ECGS a year ago and ended up pulling the e locker out of my 11+ housing and buying an 05-10 rear for $100 to put it in. 5.38s in 11+ are not possible until an aftermarket company steps up and makes new ones

 

[RunningProblem]

	Major Diameter	Ground Hub Diameter (R)	Length Thru Hole (Q)	Cenerline to End (s)	C' Bore Depth	Style	End Yoke Assembly	Slinger/Plug Part Number	Spicer Part Number
37 spline	1.609​	2.5​	2​	4.312​	0.24​	BS	3-4-11081-1X	231872​	3-4-9931-1
31 spline	1.343​	1.815​	1.64​	3.5​
31 spline (1410)	1.343​	1.812​	1.64​	3.5​

PDF Page 22 has a picture with letters to match the measurements.
PDF Page 24 has the measurements for the 37 spline yoke.

https://media.spicerparts.com/cfs/files/media/DxTnY2spgbjMjTzha/j300-p4.pdf?store=original

Length Thru Hole (Q) is probably what you're going to want to figure out. Will the extra 0.36" fi into your pumpkin or not. Is there a difference in the length of the snout, or whateer it is called, where the yoke sits on a 2011 compared to a 2008.

 

[DocRamsay]

It is the earlier pinion that won't work in the 11+ housing. I went down this road with ECGS a year ago and ended up pulling the e locker out of my 11+ housing and buying an 05-10 rear for $100 to put it in. 5.38s in 11+ are not possible until an aftermarket company steps up and makes new ones

Any issues with the E locker? Trying to save a few bucks over here.

 

[gozuki]

As a ME, the factory elocker is a form of porn. It has yet to prove itself to me functionally though, as my build has stalled out atm.

 

[wt91]

Edit: went back and cleaned this up and redid the measurements all in imperial.

Picked up the '08 axle and blew it apart immediately to get the answer.



On the left is the 37 spline pinion with the outer pinion bearing race, on the right is the 31 spline with the same.

The center section castings measure to be virtually identical on the exterior. The outer bearing pocket, towards the pinion flange, is machined larger on the 37 spline, meaning less casting wall thickness.

3.00 ID, .5135 wall thickness on the 31 spline housing @ the outer bearing race pocket. Bearing pocket depth 1.740

3.25 ID, .3240 on the 37 spline same location. Bearing pocket depth 1.740

Pinion length is virtually identical. 37 spline the splines go deeper.

Pinion OD @ outer bearing surface 37spl 1.623

Pinion OD @ outer bearing surface 31spl 1.3125

I grabbed the pinion bearing puller and pulled the inner bearings off. They are not the same. 2010 and down is NP504493 and the 2011+ is the same as the ford 9.75 apparently, TRD101004.

ID of 101004 is 1.994
ID of 504493 is 1.9375

Height of 101004 is 1.5650
Height of 504493 is 1.412

These are taken off dirty bearings with my analog calipers.

Races are same OD, different heights:

101004 is 1.002
Np998236 (2008) is .978

Inner pinion bearing pocket depths:

2011+ is 1.281"
2008 is is 1.267"

The TLDR of this whole thought experiment:

They don't easily interchange. If someone was a crazy bastard and absolutely wanted to stuff a 10.25 gear set into a 2011 plus housing, you would need to machine a .125 wall sleeve for the outer pinion bearing race from the 2010 down axle to ride in. And you would need to put a .012~ spacer/shim under the inner pinion bearing race.

I, I'm not going to do any of that, I'm just going to run this older housing. I hope in the future somebody comes out with a 5.38 gear set because the newer pinion is substantially beefier.

 

[F***roads]

Any issues with the E locker? Trying to save a few bucks over here.

I have had great luck so far with the factory E locker. in an 04 f150 with an 08 10.5 housing with a 2011 e locker out of pick n pull. like $110 CAN. 37" tires. I would say its a great cheap option. I'm sure its not as strong as an ARB/Detroit, but for the price I am happy thus far

 

[Rangerrod]

Any issues with the E locker? Trying to save a few bucks over here.

I talked with a shop that I can’t remember the name of about them a few years ago. They build jk’s on 40’s and hadn’t had good luck with them. He said they were going to arbs exclusively.

 

[DocRamsay]

I have had great luck so far with the factory E locker. in an 04 f150 with an 08 10.5 housing with a 2011 e locker out of pick n pull. like $110 CAN. 37" tires. I would say its a great cheap option. I'm sure its not as strong as an ARB/Detroit, but for the price I am happy thus far

I guess we'll see how it holds up to a turboed 5.3 and 43's. Ironically I started building because I was tired of breaking shit, but I can't stop myself.

I talked with a shop that I can’t remember the name of about them a few years ago. They build jk’s on 40’s and hadn’t had good luck with them. He said they were going to arbs exclusively.

I have an ARB up front, if I didn't live in Montana I'd just spool it and be done. Have been back and forth on saving the $700 or whatever the cost difference is from an ARB.

 

['84 Bronco II]

wt91

I talked with a shop that I can’t remember the name of about them a few years ago. They build jk’s on 40’s and hadn’t had good luck with them. He said they were going to arbs exclusively.

What exactly were their issues with them?

 

[Rangerrod]

wt91



What exactly were their issues with them?

It was a few years ago I don’t remember.

 

[pennsylvaniaboy]

Hmm this thread has me curious. I have modified an 2011+ housing with e locker , banking on being able to go 5.13's. But this might change all that.

 

[wt91]

Hmm this thread has me curious. I have modified an 2011+ housing with e locker , banking on being able to go 5.13's. But this might change all that.

Right now the lowest I can find available is 4.88 for the 11+ housing. I am gonna run the 2008 housing I have with the E locker and all from the 11, and 5.38s.

Somebody with the tools and know-how could definitely make an interference fit sleeve for the outer bearing pocket to install the older race + bearing. It would be an additional failure point, as you'd run the risk of the sleeve spinning in the housing or the race spinning in the sleeve.

If you didnt care about being able to remove the sleeve, you could always send it in and then weld or stake it in place. Hell could probably use some Retaining compound and a tight enough interference fit to basically make it 1 piece with the casting too.

 

[Jphillips]

I talked with a shop that I can’t remember the name of about them a few years ago. They build jk’s on 40’s and hadn’t had good luck with them. He said they were going to arbs exclusively.

I run a factory E locker in my '99 rear housing in my JK with 40's. Been in there for years, no issues at all.

 

[gozuki]

I've seen speculation that diesel pulling trucks have broken the factory e locker, but no specifics.

 

[pennsylvaniaboy]

hmmm yall have me curious now....Not sure if 4.88 is deep enough, and worried the e locker gonna go

 

['84 Bronco II]

and worried the e locker gonna go

I think it is a lot of internet bullshit. I have seen several people make posts implying or outright calling the factory ELockers weak, but have yet to see anyone post about a first hand experience or even a picture of a broken one

As for 4.88s, that isn't low enough in my opinion, but I know several people out there wheeling hard with 4.88s. You are just going to need to compensate for it with transmission or T-case gearing, but it is going to put more torque twist on the chassis and stress on the entire drivetrain. I would love to go deeper than 5.38s personally, but the only way you can do that is with low pinion Dana 60/70s, 9"-based axles, or portals. What it comes down to is do you want the extra pinion strength of the 37-spline sterling, or do you want lower gears? Plenty of people running 5.38 sterling on buggies with stickies around here, but obviously there are stronger options.

 

[wt91]

I think it is a lot of internet bullshit. I have seen several people make posts implying or outright calling the factory ELockers weak, but have yet to see anyone post about a first hand experience or even a picture of a broken one

As for 4.88s, that isn't low enough in my opinion, but I know several people out there wheeling hard with 4.88s. You are just going to need to compensate for it with transmission or T-case gearing, but it is going to put more torque twist on the chassis and stress on the entire drivetrain. I would love to go deeper than 5.38s personally, but the only way you can do that is with low pinion Dana 60/70s, 9"-based axles, or portals. What it comes down to is do you want the extra pinion strength of the 37-spline sterling, or do you want lower gears? Plenty of people running 5.38 sterling on buggies with stickies around here, but obviously there are stronger options.

ECGS guy when I called said something to the effect of "the industry is starting to see the demand, so keep your eyes open" regarding deeper gears for the 37 spline.

 

[gozuki]

Plenty of people running 5.38 sterling on buggies with stickies around here, but obviously there are stronger options.

Objectively, the Sterling seems on par with the 14 bolt. Without the deflection bearing.