If this is in the wrong place I apologize. Im just curious why more rigs aren’t running 2.5 ton axles. Ive been hunting a good pass drop 60 forever with no luck, but i see 2.5t sets everywhere, most between $1-2k for front and rear. Is it too much work to fit them in, clearance issues, weight??? I know alot of mud trucks run them. I haven’t studied them much but i would think even in stock form the strength would be there to hold up to big tires and torque. Any thoughts?
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
2.5 ton axles
- Thread starter WALREC
- Start date
They have their place but in most cases a bolt in dana 60 still can hang with 44s. Thats the part where they start blending in use. Where the 60 breaks rocks begin.
So, for most people rocks are just too big.
So, for most people rocks are just too big.
Are you referring to above the axle,, clearance between chunk and truck itself during suspension travel?
most of the time the clearance issue is between the top of the center chunk and the bottom of the oil pan.
As obijuank5 said, a d60 with just some upgraded 35 spline outters can handle up to a 44” tire alright, but you start finding the limit past that. A stock Rockwell is as strong (maybe a little stronger) than a d60 with some aftermarket goodies thrown at it. If you really look around, there have been quite a few guys who have done 2.5’s under square’s that are not just big mud truck guys. My brother and I have found about the lowest you can go on suspension and still have clearance for articulation is about 8” of lift in the front. Plus need to do an ORD engine crossmember to gain that little more clearance from the crossmember to the top of the center chunk. But the reality is if your running 2.5’s than you should be looking for 44” plus tires anyways, so a little taller isn’t that bad.
but most guys don’t do them cause it is a smidge more work to get them bolted up under there as compared to the true bolt in affair that a standard GM d60 is. And most guys stay around the 40-43” tire anyways, and a d60 can handle that…so that’s why they do it. But having 2.5’s under there does add the bitchin factor for sure. 2.5 tons are such a cool axle that are crazy easy to work on and are really strong, and their aftermarket support has got a lot better over the years
but most guys don’t do them cause it is a smidge more work to get them bolted up under there as compared to the true bolt in affair that a standard GM d60 is. And most guys stay around the 40-43” tire anyways, and a d60 can handle that…so that’s why they do it. But having 2.5’s under there does add the bitchin factor for sure. 2.5 tons are such a cool axle that are crazy easy to work on and are really strong, and their aftermarket support has got a lot better over the years
Couple more pics of that build
Oh also, to help with crossmember and oil pan clearance on the center chunk, moving the axle as far forward as you can is highly recommended. Mine is pushed forward about 4” from stock.
Again, this is things you need to do if you don’t want to go crazy tall mud truck style truck and you want a lower lift with Rockwell’s. If going tall mud truck, than things like that don’t really matter
Again, this is things you need to do if you don’t want to go crazy tall mud truck style truck and you want a lower lift with Rockwell’s. If going tall mud truck, than things like that don’t really matter
Here’s my brothers K5. It looks all hacked up, but it’s still leaf sprung with full factory frame. Our suspension setups on both our trucks are very similar 
6.72:1 gears in them . can be a win or loss depending on tire size and max mph you want to do .
parts are BIG and HEAVY . plan on lifting help and engine hoist if you need to pull a center chunk .
front axle is wide and if you wish to make it closer to our width needs then cut and shorten long side to a short side spec and pop in a short side shaft .
there TALL like others have said the fronts can cause oil pan / frame/crossmember problems unless custom work is done .
brakes are drum factory . aftermarket has disk for each wheel but crazy money . and some states driveline is NOT legal .
there is pros and cons for these axles for sure but by the time you rebuild one to fit easy and work good you might better buy a 60 front .
parts are BIG and HEAVY . plan on lifting help and engine hoist if you need to pull a center chunk .
front axle is wide and if you wish to make it closer to our width needs then cut and shorten long side to a short side spec and pop in a short side shaft .
there TALL like others have said the fronts can cause oil pan / frame/crossmember problems unless custom work is done .
brakes are drum factory . aftermarket has disk for each wheel but crazy money . and some states driveline is NOT legal .
there is pros and cons for these axles for sure but by the time you rebuild one to fit easy and work good you might better buy a 60 front .
On the weight thing, that isn't really that big of an issue. People forget about how heavy a d60 really is, let alone if you start trussing them up too. A de-brake'd Rockwell is almost the same amount of weight as a fully dressed d60. That is something that gets over exaggerated often with 2.5 tons. Yes pulling the center chunk is big and heavy, but as mentioned a simple engine hoist does that job not that bad by yourself.
And the fix for the width of the front axle you mention is incorrect too. All you have to do is flip the hubs in and you have the same WMS as a standard 1 ton front axle. The hub flip is crazy simple and only took me about an hour to complete.
And ditching the drum brakes is the first thing anyone wanting to swap 2.5 tons into their truck and wheel it should do. Yes, you are correct that wheel end disc brakes are crazy money, but pinion brakes are pretty cheap and really easy. Yes some states pinion brakes are not legal, but again, if you're building an off-road only rig, you don't care about that. If you do want it to be on the road to care about that law, than you probably shouldn't be looking at 2.5 tons anyway.
The reality is, just as you mention, there are benefits and drawbacks to both. It just depends on how you wanna build your truck. If goin to be a full on crawler, 2.5 tons are a really good option with strength, simplicity, etc. of the axle (pinion brakes are so simple and really nice...but you don't wanna go too fast for too long with a standard pinion brake setup or you can burn em up fast, haha). Also the steering degree of a d60 is a little better than a Rockwell too. If you still wanna drive your truck some, or you want more of a bolt in affair on a square body truck, d60 all the way as aftermarket support is fantastic and they have the strength with some goodies added to them to last up to a 44" tire pretty well. You really beat on it hard with a larger tire, you'll find the limits of that d60 though. It's a give and take and depends on the direction of your build
Last edited:
shows how behind i am on 2.5 tons . 
my info was old school . . we dont get much military axle stuff around here anymore .
my info was old school . . we dont get much military axle stuff around here anymore .Guys i really thank you for all the info and experience yall are passing along. i was mildly interested in the rockwell option when writing original post but after reading all the input, i must say, im now extremely intrigued. the money and availability are a major factor (as well as the bitchin factor Kay86k5). the way my mind is working is,, i can get a set for $1800 in good condition, so to keep the math simple, i look at it as 900 for frt axle plus 1100 for an air locker. 2k for frt same for rear,,,4k and its rolling locked. by the time i find, buy, rebuild w upgrades, and locker n truss,,, ive got 4kplus spent just on the frt. As far as mods, i enjoy mods and fab work so all the suspension and body mods n trimming n such is something i look forward to. im still not 100% sold on rocks but definitely leaning hard that way. thats just my thinkin on it.
Another thing to consider, if you go pinion brakes, is you should have a full time locker. Cause if you think about it, if the diff is open (like rocks are factory) and you do pinion brakes, once you hit the gas, you’re only stopping one tire as the spider gears are working. I honestly prefer either a mini spool or just welded spiders as the Yukon locker can still ratchet a little (like a Detroit locker does). Another reason why rocks are great for OHV only rigs that don’t really care if the spiders are welded front and rear. Just something to think about
In that case,, the money saved on frt locker could go towards the $1300 disc brake conversion kit. would probly still put air locker in rear,,, sure it will still be runnin up n down the paved rd to shop from time to time.
