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Discussion Starter · #1 ·
So I've been running smaller axles than most agree is safe with my V8 and 39" stickies for a while and this weekend it finally got me. My 8.8 Ox locker grenaded. The locker is 3 years old and the warranty period is 1 year. Just to be clear, I'm not blaming Ox and their FAQ's do state to contact them anyway outside of the warranty period as they believe the locker should be good for life...which I did this morning. Maybe they will help and maybe they won't. Plan A is to rebuild the locker and carry on. Hopefully they're willing to help out and warranty my locker but if not, I can order all of the damaged parts for about $550 and effectively have a brand new locker again. The only catch to this plan is the pinion gear in my 8.8 has maybe 5-10% of the leading edges in the teeth chipped. Some of it is in the contact patch but not a lot. If I do have to regear, the price difference between the two starts getting really close.

Plan B is dump the 8.8 and upgrade to the Ford 9 with 35 spline axles. Quick and dirty math shows about $1300 for a junkyard axle, spool, gears, bearings, axle shafts, brackets, truss, pinion yoke, and a pinion guard. However, it seems like there are 100 different Ford 9 axles out there. I'm guessing late 70's/early 80's F-150 are the best candidate with a 65" WMS but I'm confused on the third member. Looks like some are crap, some are great, and some come with the "Daytona" style pinion support which it looks like I need for 35 spline axles. Are there any trucks in that era that didn't come with the big bearing/big housings or is it a total crapshoot? Most junkyards around here are pay and pickup rather than scout and pull yourself so I don't really get to pick what I want other than year, make, model, and gear ratio.
 

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Think Outside the Catalog
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I'm not 100%, but I recall that the 9" pumpkin is really big compared to the 8.8. My plan B would be a Dana 60 rather than a Ford 9".
 

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Discussion Starter · #3 ·
I'm not 100%, but I recall that the 9" pumpkin is really big compared to the 8.8. My plan B would be a Dana 60 rather than a Ford 9".
My understanding was that the 9 hangs down maybe 1/2" lower than the 8.8 but it is wider. Why I can't find anyone that has measured both is beyond me though. That said, the 60 is considerably larger than the 9 in both the vertical and horizontal directions and probably close to double the weight. I want to say that you need to shave the 60 just to get close to the size of the stock 9. Either way, I know the 9 can be shaved down to be smaller than the 8.8 especially when run at steep pinion angles like I would have to run. The FF 60 is kind of nice but not sure it really matters for my lightweight Jeep.
 

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39" tires are outside of my comfort zone on an 8.8 or a junkyard 9". You could probably build the 9" to last, but it will be expensive (likely not junkyard parts). If you really want to spend some money, go with the Hi 9.

I agree with the FF 60 suggestion. You're in tons territory with sticky 39s, and the quicker you get there the better.

Chipped teeth...Are you using the skinny pedal a lot when wheeling? Is your gearing correct? I assume you're crawling and not rock bouncing? If you're determined to use an 8.8 or 9", then you might want to modify your driving style? If your driving style is good, then you're probably just overloading the axle and will continue to have failures in the future.
 

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Discussion Starter · #5 ·
39" tires are outside of my comfort zone on an 8.8 or a junkyard 9". You could probably build the 9" to last, but it will be expensive (likely not junkyard parts). If you really want to spend some money, go with the Hi 9.

I agree with the FF 60 suggestion. You're in tons territory with sticky 39s, and the quicker you get there the better.

Chipped teeth...Are you using the skinny pedal a lot when wheeling? Is your gearing correct? I assume you're crawling and not rock bouncing? If you're determined to use an 8.8 or 9", then you might want to modify your driving style? If your driving style is good, then you're probably just overloading the axle and will continue to have failures in the future.
Thanks for the input. The chipped teeth were related to shrapnel floating around inside the case from the damaged locker. I'm actually pretty gentle on the throttle and my rig is really light at about 4000lbs with a full tank of gas. I ran 38.5x14.5 TSL's at 3psi for a year before upgrading to the 39 stickies and have been running them for a year as well. This is the first legit breakage I've had that wasn't the result of crappy used/worn out parts or improper installation. Those breakages were related to my front D44 and old worn out RCV's that I didn't install properly so I'm not blaming the parts and instead blaming myself. Maybe that's wrong but that's how I see it.

IMO both the D60 and Ford 9 axles won't hold up in stock form and a comparably modded 35spline Ford 9 wins in strength over a 35 spline 60 in my mind. Funny thing is, if I don't get a FF D60, the axle shafts are the same between the D60 and 9. Part of the reason I feel I'm able to be gentle on my rig is because everything is tucked up so high that I rarely drag diffs or belly so adding a big diff in the back will force a more aggressive driving style.
 

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It sounds like a built 9 will work for your needs. If you were to step up, I would skip the D60 and go right to a 14 bolt. You can shave a 14 bolt to have slightly more clearance than a D44 and its way stronger than a comparable D60
 

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Discussion Starter · #7 ·
It sounds like a built 9 will work for your needs. If you were to step up, I would skip the D60 and go right to a 14 bolt. You can shave a 14 bolt to have slightly more clearance than a D44 and its way stronger than a comparable D60
I've been resisting the 14B axle for a long time because of how big and heavy that thing is. If I do ever go that route, it would be a 14B rear, 05+ D60 front, new beadlock wheels, and might as well step up to 42" or 43" tires. Probably better off starting over though. I think that is a different build altogether.

Still no word from Ox. However, I've found a few sites where I could just order the Ford 9 center section with gears and spool installed, clean housing with ends of my choice, and 35 spline shafts for around $1600 delivered. I'd still have to spend another couple hundred for the truss, brackets, and pinion guard but $500 extra for everything assembled and shipped to my door is intriguing over buying a used axle, hope it's good, and do all the work myself.
 

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I've been resisting the 14B axle for a long time because of how big and heavy that thing is. ...I think that is a different build altogether.
I like your current strategy of staying light weight. I contemplated going to tons in the past, and even had a pair of axles at one point. In the end, I decided to stay nimble and light on 35" tires with my 8.8 rear and HP Dana 44 front (both full width). Most of my friends are on tons now, with larger tires, but I hang with them on most obstacles. The shorter YJ wheelbase seems to cause me more issues than tire size.
 

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The biggest problem with a 9 inch is how low the pinion is.
If I remember right it is lower than any other diff.
 

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Discussion Starter · #12 ·
Well from what I can see the 9's length from axle centerline to yoke is about the same...maybe the 9 is a little shorter but it also depends on the yoke itself. I know my pinion currently points up at about a 25 degree angle at ride height so it does make me wonder how much the lower pinion would really make. For sure it would make a difference but I have to have a center limiting strap anyway so maybe I'd never notice once the strap is adjusted.
 

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IMO both the D60 and Ford 9 axles won't hold up in stock form and a comparably modded 35spline Ford 9 wins in strength over a 35 spline 60 in my mind. F
I've heard this more than once. Got 39s sitting in my back yard and contemplating running them on my Super 88 8.8 or going the 9 route, I like the keeping it light route. Subbed for great info.
 

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Discussion Starter · #14 ·
I've heard this more than once. Got 39s sitting in my back yard and contemplating running them on my Super 88 8.8 or going the 9 route, I like the keeping it light route. Subbed for great info.
Just my opinion but I really think driving style is the biggest factor. Guy in my group with a TJ broke his D60 rear with Yukon axles attempting the same line I walked up over the summer. He had the Jeep engine instead of my V8 and was running old 37's inflated higher than my new sticky 39's. Broke his 60 and my 8.8 was fine... He uses more skinny pedal IMO though and doesn't really have the finesse.
 

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Just my opinion but I really think driving style is the biggest factor. Guy in my group with a TJ broke his D60 rear with Yukon axles attempting the same line I walked up over the summer. He had the Jeep engine instead of my V8 and was running old 37's inflated higher than my new sticky 39's. Broke his 60 and my 8.8 was fine... He uses more skinny pedal IMO though and doesn't really have the finesse.
Totally agree, you don't have to floor it everytime
 

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When I started playing with beadlocked 37" sticky territory I was warned by a few highly trusted wheelers WRT my ARB locked S88 W/4.56 gears and Atlas 5.0. Word from them was it was a ticking timebomb where we wheeled at regularly.

Heeding that advice, I went strait to a second gen FF14B and converted it to discs which saved ~98# over the huge drums. Just an FYI if you hadn't heard about the weight saving if converting to discs. As a bonus, the freshly (brand new) regeared 14B cost me only $350 from a local guy on CL who decided to go a different route.

I use to wheel with several folks running various version 9". Most had very little trouble with them even while running 40" stickies in the big rocks. Great axle if built properly IMO.
 

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I would bet that there is a good chance that you repeat your success and get good life out of an 8.8 if you did 35 splines, etc.

I feel certain that you will have even more sucess using a 9". Pinion hangs low, you covered that with it is pointed upward pretty significantly. It is possible to put a D60s strength in areas of a housing that still uses a smaller lighter diff package. You are on to that. I think it sounds like the perfect fit for the way that your Jeep is really built.

Here is another point. If you blew up your LS motor or even had a trans failure. Would you think that you now need to upgrade your engine and trans or would you accept it as part of the cost of playing with big boy toys? Probably chalk it up to stuff happens. Why do people feel that if they have ever seen or heard of a particular type of diff breaking then you need the next bigger thing at all costs and like you already mentioned in this thread where somebody in a TJ tore up a D60. So those must be bad also????

I look forward to seeing your finished solution, as usual. This thread is a real good read.
 

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Discussion Starter · #18 ·
When I started playing with beadlocked 37" sticky territory I was warned by a few highly trusted wheelers WRT my ARB locked S88 W/4.56 gears and Atlas 5.0. Word from them was it was a ticking timebomb where we wheeled at regularly.

Heeding that advice, I went strait to a second gen FF14B and converted it to discs which saved ~98# over the huge drums. Just an FYI if you hadn't heard about the weight saving if converting to discs. As a bonus, the freshly (brand new) regeared 14B cost me only $350 from a local guy on CL who decided to go a different route.

I use to wheel with several folks running various version 9". Most had very little trouble with them even while running 40" stickies in the big rocks. Great axle if built properly IMO.
Most guys I've met who went straight to tons say that about me as well but then they get pretty jealous when I tip toe over giant rocks that they drag diffs on.

I would bet that there is a good chance that you repeat your success and get good life out of an 8.8 if you did 35 splines, etc.

I feel certain that you will have even more sucess using a 9". Pinion hangs low, you covered that with it is pointed upward pretty significantly. It is possible to put a D60s strength in areas of a housing that still uses a smaller lighter diff package. You are on to that. I think it sounds like the perfect fit for the way that your Jeep is really built.

Here is another point. If you blew up your LS motor or even had a trans failure. Would you think that you now need to upgrade your engine and trans or would you accept it as part of the cost of playing with big boy toys? Probably chalk it up to stuff happens. Why do people feel that if they have ever seen or heard of a particular type of diff breaking then you need the next bigger thing at all costs and like you already mentioned in this thread where somebody in a TJ tore up a D60. So those must be bad also????

I look forward to seeing your finished solution, as usual. This thread is a real good read.
I guess I had never even considered 35 spline axles in the 8.8 but I see that is an option. Interestingly, it's only a little more than just fixing my locker. Granted, I'd have a spool but I was debating that with the 9" anyway. Out of curiosity, what should I do to ensure the axle housing itself will last if going to axles and a spool that big?

I think one other option I have that's virtually free is converting my old LSD diff to a lincoln locker. May verify the gears are ok prior to spending money to upgrade the 8.8. Although, if the stock carrier is weak, that may be a bad idea.
 

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I guess I had never even considered 35 spline axles in the 8.8 but I see that is an option. Interestingly, it's only a little more than just fixing my locker. Granted, I'd have a spool but I was debating that with the 9" anyway. Out of curiosity, what should I do to ensure the axle housing itself will last if going to axles and a spool that big?

I think one other option I have that's virtually free is converting my old LSD diff to a lincoln locker. May verify the gears are ok prior to spending money to upgrade the 8.8. Although, if the stock carrier is weak, that may be a bad idea.
I was not trying to encourage you to keep the 8.8 but did point out how well it lasted and that it could be built even stronger than what you have had. Axles are a big upgrade for sure. I have stumbled across different builds where tubes have been upgraded by replacement or sleeving or even a build that had the larger axle bearing ends from a 9" installed onto it. Some of it gets pretty custom and a lot of it is more directed at drag racing, etc. but it all applies IMO. Another mod is to run a girdle cover. Making sure that the axle tubes are welded is a must. A full spool would be stronger than a carrier. Mini spools break easier than full spools. Moser engineering is somebody that I would talk to if I were you. They even offer 40 spline axles but it requires other machining. They would be more informed about the limitations than I would be. Trussing any diff is obviously going to strengthen it. I have seen 8.8s run in 9 second cars. They can be made stronger than people think IMO.

I believe your upgrade to a 9" would be all that and a bag of chips. Quick performance is big in the drag racing side of things and has a lot of 9" upgrade info. Moser should also have info on those.

Honestly, it is your Jeep that really opened my eyes that you do not need or even necessarily want all the biggest and baddest, thus heaviest stuff bolted to it to make it capable. In fact, you have proven the opposite to be true. Tons are just so big and so heavy.

EDIT: The vehicles I worked on in Afghanistan were Mine Resistant Ambush Protected (MRAP) vehicles. Ours was the lightest of all the variants at about 40K lbs. They were 4 wheel drive with very large Axletech diffs in them. Both diffs and the T-case were fully lockable. Anyways, we started to experience occasional breakage in them and found that most times the breakage occurred with the lockers engaged and going downhill in looser terrain where a wheel could slip over a rock while the other had good footing and appying the brakes. Just some food for thought.
 

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I do not have near the experience of others hear but I have read a lot. I also have seen what Nate (dirtlifestyle) and Kelly (Muddybeards4x4) have done with their Ford 9" rear axles on their Jeeps. I do agree with your approach on staying lighter. Weight definitely causes lots of stress on parts. I personally would upgrade to a 9", do all the things that were mentioned above. If Ox says they will replace your stuff or give you a discount on repairs then maybe just beef up the 8.8. I do think though if i were to spend a decent amount of money, anything more than a locker i would upgrage my axle.

Definitely following along because one day I would like to get a Ford 9".
 
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