Ford 9" gear swap w/ LS/Locker Questions

[edgeoffroad04]

Happy to say I utilized the search feature and found a ton of threads of gear swaps and traction devices. (what a great site this place is!)

Long story short I am looking to change gears in my Small bearing 9 inch.(have 4.11s) going to 4.56's. With out going down the rabbit hole too far I would like to upgrade to 31 spline shafts as I am running 35s and swap to a LS or locker.

Cost is a concern on type of traction device, but as I have learned spend the money once to avoid doing the job a second time to be totally happy. Part of me thinks a True Trac will be fine as an LS and great on road, but would it be enough if I get into moderate trials with rocks/roots.

The truck is mostly street driven now but I want to do more mild to moderate trails in the area NE OHIO/Michigan. Normally its a sand dune rig when offroad.

I am open to doing the work myself but I have never done a gear or carrier swap before. Makes me a little nervous but with some patience I am sure I could figure it out. From reading other threads the 9" is a good place to learn to swap out gears. Can anyone give me a list of the tools I would need to purchase to do this on my own? Any watch outs?

Also any North East Ohio guys around? Would like to meet some other EB owners.

 

[SteveL]

Starting with gears the 9" is easier than the 44 to set up especially if you go solid spacer in place of the crush sleeve.for mostly street the true track should be enough until it isnt. At that point you probably want to spend the $$ on an arb to keep the road manners. At least once the pinion is in and set it isnt too bad to swap carriers later.

 

[tirewater]

I've just rebuilt my stock 9". Some tips:

Buy the Ford 9" assembly stand. It makes life much easier, and things more enjoyable. Here is one from Jegs, but they appear to be all the same:

I bought the Summit Branded tracloc and gears. Generally I've had good luck with Summit's private label stuff, but if I were doing it again I'd spend the extra $100+ for good quality name brands. The carrier I had to send back as run out exceeded spec. This was a big waste of time and energy as I had assembled it, tore it down, re-assembled it, etc...then got a replacement. As for the gears, it was hard to get an acceptable pattern - and the pattern varied quite a bit across teeth.

Happy to say I utilized the search feature and found a ton of threads of gear swaps and traction devices. (what a great site this place is!)

Long story short I am looking to change gears in my Small bearing 9 inch.(have 4.11s) going to 4.56's. With out going down the rabbit hole too far I would like to upgrade to 31 spline shafts as I am running 35s and swap to a LS or locker.

Cost is a concern on type of traction device, but as I have learned spend the money once to avoid doing the job a second time to be totally happy. Part of me thinks a True Trac will be fine as an LS and great on road, but would it be enough if I get into moderate trials with rocks/roots.

The truck is mostly street driven now but I want to do more mild to moderate trails in the area NE OHIO/Michigan. Normally its a sand dune rig when offroad.

I am open to doing the work myself but I have never done a gear or carrier swap before. Makes me a little nervous but with some patience I am sure I could figure it out. From reading other threads the 9" is a good place to learn to swap out gears. Can anyone give me a list of the tools I would need to purchase to do this on my own? Any watch outs?

Also any North East Ohio guys around? Would like to meet some other EB owners.

 

[Vincen]

I am from Medina county. I have a 70 U15 that’s currently under construction.

 

[SteveL]

Oh yeah. Buy decent gears. The cheap ones are harder to get a good pattern

 

[Nothing Special]

.... Cost is a concern on type of traction device, but as I have learned spend the money once to avoid doing the job a second time to be totally happy. Part of me thinks a True Trac will be fine as an LS and great on road, but would it be enough if I get into moderate trials with rocks/roots.

The truck is mostly street driven now but I want to do more mild to moderate trails in the area NE OHIO/Michigan. Normally its a sand dune rig when offroad....

A TrueTrac is probably a good choice for that usage. It's not a locker, and you'll find it lacking if you get twisted up enough to start lifting tires. But as long as both tires get at least some traction it does really well.

 

[77Bronco636]

I just redid my 9" after blowing the posi out of it...I did the math of buying everthing I needed to go up to 31 spline axels, Detroit locker, tools, books, and my time, and it just made sense to me to buy a new 3rd member set up how I wanted (I now have a nodular case, everything is new, I'm running 31 spline axels, I have a locker, and a warranty). I do not plan on switching gears back and forth so if that is something you plan on doing then diffently learn to do it yourself and get the tools you need (it will pay off for you). I am running 33"x12.5" tires with a locker on the street and have not had any issues with it (it will chirp around corners but nothing major) just something to think about if you do want to got he locker route.

 

[edgeoffroad04]

@Tirewater good call out in the 9" stand and buying quality gears. I was planning to buy gears from one of the Vendors.

@Vincen- where in Medina County? I live in Montville Twp


@Nothing Special- the TrueTrac seems like a safe bet..but this is a fair weather summer/fall vehicle. need to weigh the options more.

@77Bronco636- where did you you go to get your new 3rd member from? Do you notice the locker causing any drivability issues on the highway?

Any recommendations on preferred brand for gears guys?

 

[77Bronco636]

@Tirewater good call out in the 9" stand and buying quality gears. I was planning to buy gears from one of the Vendors.

@Vincen- where in Medina County? I live in Montville Twp


@Nothing Special- the TrueTrac seems like a safe bet..but this is a fair weather summer/fall vehicle. need to weigh the options more.

@77Bronco636- where did you you go to get your new 3rd member from? Do you notice the locker causing any drivability issues on the highway?

Any recommendations on preferred brand for gears guys?

I bought my 3rd member from Bronco Graveyard (they use Yukon gears and I do believe they are set up in Iowa and come with a "crush sleeve" so no guess work when installing your yoke) and my axels from Wild horses (I went with the extreme duty 31 spline with the Timkin roller bearings, they are Yukon axel shafts, it was worth the shipping price as they came ready to bolt in, bearings and seals pressed on them already, so far I'm please with the choices I have made and had help from members on here to make my decisions. A local buddy of mine is running a Detroit locker also on the street (90% of the time on road 10% off road) and he also has had no issues....if buying gears straight up go with Yukon.....bearings I would always go with Timkin......just my thoughts!!! Good luck with your upgrade!!!!

 

[77Bronco636]

@Tirewater good call out in the 9" stand and buying quality gears. I was planning to buy gears from one of the Vendors.

@Vincen- where in Medina County? I live in Montville Twp


@Nothing Special- the TrueTrac seems like a safe bet..but this is a fair weather summer/fall vehicle. need to weigh the options more.

@77Bronco636- where did you you go to get your new 3rd member from? Do you notice the locker causing any drivability issues on the highway?

Any recommendations on preferred brand for gears guys?

As far as highway driving, I'm running 4-11's with 33"X12.5" tires, at 60 MPH I'm at 3200RPM's so I dont go on the highway around here as It would be suicide.....as far as the Detroit locker on the road it has not been an issue....it "chirps" around tight corners and it "chirps" if I goose the throttle....it just reminds me that if I drop the hammer I'm gonna hook up!!!;D or spin out!!

 

[Nothing Special]

I've had lockers in the rear axle of three vehicles, including my '71 Bronco. They definitely aren't for everyone on the street, but I don't mind driving one.

The thing about automatic lockers is that when you go around a corner they automatically unlock so the outside tire can roll faster than the inside tire. That means you are only driving the inside tire (yes, with all the rhetoric of an open diff being one-wheel drive, that is actually what an automatic locker does). So if you get on the gas too hard in a corner it's really easy to break that one tire loose. As 77Bronco636 says, that makes the tire chirp, and if you don't get off it soon enough can make you swap ends.

In addition to that you also get some weird torque steer as you get on and off the gas (much more noticeable with a manual trans than an automatic). This results from the one-wheel drive again, because you are pushing on only one side.

If you value the performance when you need it, and are willing to pay attention to the vehicle (meaning mostly not get on the gas too much in a corner) you will find an automatic locker pretty easy to live with. I've even driven them through about 12 Minnesota winters. But if you don't need one, or if you don't want to deal with the quirks, you probably won't like living with one. It will make itself known pretty frequently.

On the other hand a TrueTrac will be essentially invisible on the street (although it will swap ends easier than an open diff on ice or snow). And it will be pretty good off-road as long as you keep all four tires on the ground. For mild to moderate trails and sand I think it would be a good choice.

An automatic locker will be better off-road but less good on. A TrueTrac will be better on road but less good off. And what we haven't talked about is a selectable locker that's great on road, great off-road (although some of us do prefer automatic lockers off road), but more expensive. Personally my choice is an automatic locker in the rear (and a selectable in the front). But you need to make your choice.

 

[kylakekevin]

I could not of said it any better Nothing Special.

 

[edgeoffroad04]

Thanks everyone for the knowledge! The only thing missing is taking a drive in a Bronco with an automatic locker vs. the Truetrac.

 

[5001craig]

Too bad you're not NW OH instead of NE OH. I'd give you a ride in mine with Grizzly's.

 

[edgeoffroad04]

@5001craig...I have seen your build(awesome set up!) and I too love the Dunes...wish we were closer. I'm still holding out I can make it to The Bronco Take Over in August. How do you like the Grizzly lockers? Street/off road manners thoughts?

Has anyone heard of durability issues with a TrueTrac with 35's?

 

[5001craig]

I like the Grizzly lockers but my rig is fairly purpose-built. I don't drive it on the street that much. When I do drive it on the street I'm a little cautious coming out of turns with my 3K torque converter and the way these go from unlocked to locked under throttle. Mine jumped sideways once when I got into it a little too quickly. My buddy thought it was cool but I had to change my underwear.

If I was building a street rig it wouldn't have these diff's. I would probably either go with open diff's on a stock build or a selectable locker if the rig was built with some power just to ensure two black marks when I wanted them. These things are so short that when the rear end breaks loose things happen fast.

You really need to make the trip to Silver Lake Sand Dunes at least once. Nothing like seeing a ton of EB's on the sand.

 

[blubuckaroo]

I wouldn't eliminate a good limited slip from your options.
Sure you'll need to add friction additive, and the clutches aren't totally maintenance free. But auto trannys use clutches too, and that hasn't kept anyone from using them.
Yukon makes a great limited slip unit. You can select from two different lock-up pressures.
The thing I like about an LS over the True Trac is the LS will still work if you get one wheel in the air. With the True Trac, you have to tap the brake to get it to lock up.

 

[SteveL]

Nice pics.

 

[edgeoffroad04]

Great pictures! Fortunately I used to go every summer. But with the addition to the family priorities do change.

 

[Nothing Special]

I like the Grizzly lockers but my rig is fairly purpose-built. I don't drive it on the street that much. When I do drive it on the street I'm a little cautious coming out of turns with my 3K torque converter and the way these go from unlocked to locked under throttle. Mine jumped sideways once when I got into it a little too quickly. My buddy thought it was cool but I had to change my underwear....

It's a common misconception, especially be people who own them, that automatic lockers (like the Grizzly, Detroit, or lunchbox lockers) lock when you get on the power. They know nothing about power, they work only on relative speed.

When you go around a corner they unlock. The outside tire wants to roll faster than the inside tire and the locker unlocks to allow that to happen. Like I said above, that means you only have one-wheel drive. And what's worse, it's the inside rear tire, the tire with the least weight on it (weight transfers out on a corner). So if you get on the gas too hard it's REALLY easy to spin that tire. So it's the fact that it UNLOCKS that gives the bad handling, not that it locks under power.

Of course, once the inside tire is spinning it quickly catches up with the speed of the outside tire. When that happens the locker relocks. It happens after you got on the power, but it's based on relative tire speed. When it relocks it kind of hammers against the outside tire because it has the inertia of the spinning inside tire and of the entire drivetrain hitting against it. So pretty often it will break the outside tire free too.

So the end result is the same, get on the power too much in a corner and it's easy to swap ends. And the fix is the same, don't get on the gas too hard in corners. But the misunderstanding can lead to other wrong assumptions, like you need to get off the throttle to unlock the locker. You do need to not spin the tires to get it to unlock, but as long as you aren't spinning tires it will unlock freely.