28 splined locker and axles Vs 31

[bobbyray27]

Im trying to decide on a 28 splined locker and axles or a 31 splined locker and axles for my 9inch rearend . Money is tight. I have a 302 engine 33inch tires c4 tranny and 350 gears. I dont have a heavy foot but would like to try some of the more difficult trails in california. So im asking for any input on how good or bad 28 splined bronco axles are and how well they hold up when locked up?

 

[rednck21]

28 spl should be fine for 33's...but... im running a detroit and 31 spl yukons and the extra piece of mind that the bigger shafts give is worth every penny

 

[Bronco Brian]

I wheeled 28 with 35 for years broke 1 few years later up graded to 31 both axes I took out were twisted. Do 31's once and be done

28 Spline locker $500.00
31 Spline locker to replace 28 Spline $500.00
31 axles $400.00
so $400.00 more now or $900.00 later plus parts & laber

Brian

 

[76Broncofromhell]

It's a gamble. I am still running my 28 splines with a detroit in the back of my Bronco, but it's not a heavy-duty wheeler. I am also a lot easier on it knowing that I don't want to upgrade axle shafts.

It all depends on your driving style.

 

[broncnaz]

Welcome. I'd really consider going with 31 splines with a full locker. especailly with 33 in tires if you were running smaller tires 28 spline may hold up. Considering the axle are fairly old they are probalby twisted already and a locker will cause them to break faster. I've heard of people breaking stock 31 spline axles in there driveways after lockers were installed. not sure if its true or not just heard that a few times.
You might want to look into a stock type L/S they can usually be picked up for cheap and when rebuilt they work pretty good it will at least give you more traction. I've run the stock LS and it does pretty good It will usually keep you from going in over your head and will still get you in places you realize you probably shouldnt be.Then you can save up for the 31 spline stuff. complete off road just had a deal on 31 spline axles for about $230 they may still be on sale. the locker is going to cost about $500 plus another $100 for new bearings. although you could just put in a 28 spline EZ locker or lock rite they are a little cheaper$250-$300) and you probably wont need to install new bearings unless you want to.

 

[RajinCajun]

I ran a mini spool in my 9" with 28 spline axles, with 35" boggers for about 2 years sith some hard wheelin'. It was still fine when I pulled it out. I did/do have a spare set of axles, and planned to upgrade later anyway so I figured $25 for the mini spool and some oil right then was better, and would give me a few months of wheelin' until I had the $$ to upgrade.

 

[Silverhorse]

I ran the 28's for years with a mini spool and 38's,broke the rear several times but never an axle. You should be fine with 33's either way its all personnal preference.If you would feel better with the 31 spline then do it, ease of mind is worth the money!

 

[kontinu]

I decided to just go with 31 spline axles and the 31spline detroit. Spend the money once and rebuild it once. At least I know I could push it pretty hard before something breaks now.

 

[AZMike]

I've got 28 spline Yukons, a Detroit, and 4:11s with 35's. I spun an axle bearing last year on one of the stockers and replaced them both with Yukons - they were twisted a bit, but otherwise in decent shape. The 28's will hold up OK if you don't do any hard crawling. I'm pretty easy on the skinny pedal on the trail so I don't expect to break the axles anytime soon.

If you've got an auto, and are easy on the rig on the trail, they should hold up fine. If you've got a stick or you drive it like you stole it, you'll put more stress on all the driveline components and might want to go 31 spline.

 

[bronko69er]

In case you're interested,
http://classicbroncos.com/forums/showthread.php?t=95064

 

[Steve]

The 28's will hold up OK if you don't do any hard crawling.

Probably. I wheel a lot in Moab where you get amazing traction even on the 'easy' trails. I've seen a bunch of broken 28 spline shafts there; never have seen a 31 or 35 spline shaft broken there. I run 31 spline alloy shafts.

 

[Tenacious-B]

If there is some way you can squeeze out the extra $400 or so go with the 31 spline axles. You'll be much more comfortable when you get in a bind knowing those things are back there.

 

[FerrumCampitor]

If he has 28 spline now, doesn't he have to get a big bearing rear end to run 31 spline axles? Or is the bearing size independant of the axle size? I've never been clear on that.

 

[Steve]

If he has 28 spline now, doesn't he have to get a big bearing rear end to run 31 spline axles? Or is the bearing size independant of the axle size? I've never been clear on that.

31 spline shafts are larger diameter than 28 spline shafts. There are "conversion bearings" available to let you run 31 spline shafts in a small bearing housing. That's my current setup.

 

[broncoguy66]

I'm running stock '66 28sp axles with a mini spool and 35" BFG muds. I'm not hard on it, well..... no too hard. that pic to the left is the front ring gear. I've done some fairly hard stuff and so far they have held up ok.

 

[braxton357]

31 spline shafts are larger diameter than 28 spline shafts. There are "conversion bearings" available to let you run 31 spline shafts in a small bearing housing. That's my current setup.

One of the bronco part places sells 31sp axles for a small bearing housing. IIRC it's wild horses.

 

[cbearly]

If he has 28 spline now, doesn't he have to get a big bearing rear end to run 31 spline axles? Or is the bearing size independant of the axle size? I've never been clear on that.

31 spline shafts are larger diameter than 28 spline shafts. There are "conversion bearings" available to let you run 31 spline shafts in a small bearing housing. That's my current setup.

Also, just because he has 28 spline axles now doesn't necessarily mean he has the small bearing axle housing. Lots of big bearing housings came with 28 spline axles.

I've got a big bearing housing with 28 spline Yukon axles, a detroit locker and 35" tires. So far no problems. We'll see how they do in Moab this spring.

Bobbyray27 - If you are installing a locker and the axles I say go with the 31 spline. Better to spend a little more now and be happy with it than to have to spend good money to replace the stuff you buy now because you aren' t happy with it. Mine came with the 28 spline detroit locker already set up, otherwise I would have changed over to 31 spline when I put the Yukon shafts in. Just my $0.02.

 

[acbronco66]

Are the 31 spline axles that complete off-road are offering not 4340. If so they are selling them for $209.

Ross Baker
Bama Gang

 

[braxton357]

Almost every aftermkt rear axle you will find (excluding custom built stuff) will be 1541h and not 4340. Which is what those shafts are as well...

 

[67u13]

I would think you would be fine wih the 28. I had 28s in my 74 and they never broke