Went and picked up a np435/205 today and the guy had a set of GM 2.5 ton axles sitting back in a field with some dry-rotted military tires on them. Said I could have them for $200. It was 1 front, 1 rear, and another rear with the hubs missing.

What's their worth compared to the rockwells?? What gears do they likely have?? Can you get rid of the drum brakes on the front?? I wouldn't use them right away, but I'd like to pick them up and hold on to them if that's a awesome deal.

I can't tell you a monetary worth of GM 2.5tons, but i can tell you not to buy them if you are going to wheel. They are 3rd member style, not top-loaders, and so the ground clearance sucks monkey turds. Dunno much about the gear ratio either, sorry.

dont those thing have like 20" ring gears? :D

GM 2.5 ton have bigger axleshaft diameter( = 1.75" )than the Rockwells (= 1.62). BUT they are not top loaders, and this is actually almost the only reason why you would want such heavy monsters in the first place.
so, if you do'nt get an upper pinion entry to help with all that lift and tose nasty driveshaft angles, why would you want 650 lb of an axle to deal with?
oh, i forgot that with such an axle which has lousy ground clearance you can't have anything less than 44" which is another 220lb(a pair) per axle!!
coclusion = if you're not in for a huge monster, and if you can't live with the fact that you'll have at least 6000lb of a beasty weight(with the big block to go with it), just leave'm to rott there for another 20 years...
love & peace ;)

the frog

The gear ratio is 6.17. NoSpin (Detroit Locker) is available. A guy with a built F250 named "Swamp Donkey" has them on his rig. He has a Powerstroke, ZF 5spd/Spicer 3053A 5spd/NP205, the GM axles and 11.00-20s
I think they are a bit lighter than Rockwells.
Charlie

I think that shafts are kinda weak for the size, too. A kid I know has a M211 (the truck they come outa) and it had 1 broke rear shaft and 1 broke stub shaft. The rear sheared off at the splines and the stub shatterd. I am not sure how hard it was beat on to brake em, but the way they broke,it seemed like the metal was weak.
HTH

Also the GMC axles WILL NOT work with any of the transfer cases you might want to run, the front axle spins contrairy to most all other axles (front axle will go forward, rear will go in reverse and vise versa). These axles are virtualy usless without the GMC transfer case.

JYS

That is one heavy transfer too!!, the thing looks like it weighs 1000 lbs, prob not that much, but still, it is only a single speed case too... (the low on those beasts is through the range box on the hydromatic 303) It still would make an intersting swap though. While there is a thread on old military axles, i have a few Q's, I can get a 40's or 30's IH 6x6, looks to be 2.5 ton, wonder if those axles are any better?? also, there is a old militray dodge dually in a local yard, looks 1.5 ton but I could be wrong, are those axles as tough as they look??
thanks
Dan Hinckley

Originally posted by Junkyard Slug
Also the GMC axles WILL NOT work with any of the transfer cases you might want to run, the front axle spins contrairy to most all other axles (front axle will go forward, rear will go in reverse and vise versa). These axles are virtualy usless without the GMC transfer case.

JYS

so how is the guy with the above mentioned "swamp donkey" runnin em in his f250 with a 205?

not bein a smart ass,just wonderin how he made it work...

as far as the rotation on the diffs. i am currently in the process of swapping in a set of 2.5 ton gmc axles. if you rotate the housing and flip the pinion over to where it is a high pinion it will spin the right direction. i am using a second t-case to get better driveshaft angles. all is going well so far.

as far as the rotation on the diffs. i am currently in the process of swapping in a set of 2.5 ton gmc axles. if you rotate the housing and flip the pinion over to where it is a high pinion it will spin the right direction. i am using a second t-case to get better driveshaft angles. all is going well so far.
when you flip the diff the axles are the wrong length
one is to short and one is to long :(

A guy on the M715 Zone has a set of M211 axles under his M715. He did the flip of the 3rd member. It takes a bit of grinding to get it to work, and one axle has to be cut and the other doesn't engage fully, if I remember correctly. It will work, but it is no where near the same as the more "modern" Rockwells. With all that in mind, unless the axles are free and you only plan to build a pavement cruiser, leave the axles alone. Also, nothing compares to the 2.5 ton Rockwells in the older trucks. Anything pre-'50s is going to be inferior as far as design, and metallurgy.
The only thing that might be better than 2.5 ton Rockwells is a set of 5 ton axles, and they are way too big, heavy, and just plain overkill in a rock crawler. Besides, where do you think you are going to find parts for a 60 year old axle? True, there are still a lot of them around, but it's not worth the effort when the aftermarket is supporting the 2.5 ton Rockwells and it's less work to put those in. Just my .02

El, that guy is I think getting a set of Rockwells... a certain someone in PA has a set earmarked for a guy w/GMC axles in his truck currently. ;)

so how is the guy with the above mentioned "swamp donkey" runnin em in his f250 with a 205?

not bein a smart ass,just wonderin how he made it work...

See for yourself, he has an extensive website, here:

http://hometown.aol.com/jzettel73/Swamp_Donkey.html

El, that guy is I think getting a set of Rockwells... a certain someone in PA has a set earmarked for a guy w/GMC axles in his truck currently. ;)

Ahh, cool. I was trying to convince my cousin to buy those for our next project, but he's not finished with his YJ yet, so he doesn't want to spend the cash. Oh well, there are lots more of them out there, but that wasn't a bad price though. :D

Can you get rid of the drum brakes on the front??

Dunno if anybody else has found this, but I found that a 1994 Ford B700 bus rotor has the same Bolt pattern and seemingly everything required to fit onto a rockwell hub:

Outer Diameter: 15.38 in.
Height: 6.02 in.
Hub Register: 6.44 in. (Reo's are like 6.40'sh right?)
Bolt Size: .844 in.
Bolt Circle: 6x8.75

You'd have to run the hubs flipped out, unless I find the same rotor that doesnt have the u-shaped hat. Not to mention you would also need a fair sized rim unless by chance (due to backspacing) the rim would not interfere. Anyone else looked into this at all?

If what you say is true, the rockwell overpriced disc brake business might be over!! :)

If what you say is true, the rockwell overpriced disc brake business might be over!! :)

Ya I was destined to find a rotor (took a while but I think I found it) I do have a full dimensioned pic of the rotor I'll scan and put up later, there seemingly 130 bucks a piece at napa part number: 86839 (I'm going to look today to be sure), havent gotten a caliper quote yet though (these jokers are 1.50" thick).

Scratch that napa had it wrong, cheapest I've found so far was on brakewarehouse.com part number AR-8971 for 180 a piece.

Chevy D60 rotors are 1.5" thick too. Modding the brackets would likely bet the hard part. I don't have any experience with rockwells at all but I'm sure it can be done.

If so, I might have to get me a set of rockwells for a buggy in the future.

Chevy D60 rotors are 1.5" thick too. Modding the brackets would likely bet the hard part. I don't have any experience with rockwells at all but I'm sure it can be done.

If so, I might have to get me a set of rockwells for a buggy in the future.

You have an exact year and model with the 1.50" thick? It would help because the cheapest loaded caliper I'm finding so far is 163.99 (core added). Would help to take a simple trip to the local auto parts store. :D

Oh and the way it seems fabbing a mount off the Spindle bolts would be easy but I have to take a closer look

I see what your talking about now, I'm so used to looking at C20 calipers (self supported bolt on), I figured C30's would be the same. I guess finding a bolt on caliper that accepts a 1.50" thick rotor.

There will likely be no "bolt on".... the trick is to find a caliper that's going to easily mount to a flat plate that engages, on the other side, the 1/4" bolts that hold the spindle on.

Thanks for the tech on the disks up front. I found a very easy way to mount up 2wd F250 disks and calipers to a rear rockwell...

http://www.planetbantz.com/imghost/bob/rockwellhubs_2.jpg
http://www.planetbantz.com/imghost/bob/rockwellhubs_3.jpg
http://www.planetbantz.com/imghost/bob/rockwellhubs_4.jpg

i think the school bus to which you are reffering uses a rockwell axle.

I as well came up with a way to mount a vaned rotor onto the rockwell hub. This process could also be applied to front flipped in hubs, but it would require a 15" vaned rotor (225 a piece).

http://tellico.off-road.com/wwwthreads_uploads/1430688-wheelbrake2.JPG
http://tellico.off-road.com/wwwthreads_uploads/1430687-wheelbrake1.JPG
http://tellico.off-road.com/wwwthreads_uploads/1430689-wheelbrake3.JPG
http://tellico.off-road.com/wwwthreads_uploads/1430690-wheelbrake4.JPG

Oh and I think a 2000 Chevy C3500 is self supported bolt on, just want to look further into the piston size and rotor thickness.

Here's the dimensional printout and picture of the rotor I found:
http://tellico.off-road.com/wwwthreads_uploads/1433308-busrotor.JPG

studlybilly, can you post some more pics and details on your brake setup there? There are a fawkton of people who would love to be able to make their own setup instead of shelling out thousands for a kit.

studlybilly, can you post some more pics and details on your brake setup there? There are a fawkton of people who would love to be able to make their own setup instead of shelling out thousands for a kit.

Yup, the rotors are 27.50 a piece. I have a patent pending but as long as nobody markets it I dont mind at all, hell I'm just another guy pinching pennies myself, I gotta upload the other pics. Basically it does require minimal machining of the hub, and 1/4" plate. If you can wait til tomorrow I'll go real in depth with it, be advised its only a 11.750" rotor so if you need more stopping power you'll reach into the 13"rs (149 a piece) or a 15"er (225 a piece). Do you want to know how to do it with the hubs flipped in or out?

I'd rather wait till tomorrow to hear the good shit than to hear a brief version and burden you with questions now. If you've got time then please dicuss in and out. I've got mine in right now, but would be willing to flip them out in order to make things work. I've got 48" Michelins on stock 2 1/2 ton rims with tubes, so it's pretty heavy. I plan on running disks front and rear, so what size rotor would you suggest?

Just to let everyone know, brakewarehouse.com has economy versions of the rockwell rotors for 95.99, your gonna pay about 40 bucks in shipping a piece but its much more affordable.

Drivetime I havent forgot about ya, if you want Pm me with your Aim Sn or email or something so were not pirating this thread anymore. :D

hi 'billy..

wanted to reopen this for a min and find out if you ever located any 15"+ rotors to use on these front rockwells.

I emailed a company called gunite lopoking for all the specs on their big rotors, but none of them seem like they are small enough in depth.

any pointers would be appreciated.

hi 'billy..

wanted to reopen this for a min and find out if you ever located any 15"+ rotors to use on these front rockwells.

I emailed a company called gunite lopoking for all the specs on their big rotors, but none of them seem like they are small enough in depth.

any pointers would be appreciated.

studlybilly and I both made setups using the rotors above from brakewarehouse.com, which are over 15"

studlybilly and I both made setups using the rotors above from brakewarehouse.com, which are over 15"
I have what I need for the rear, however the same rotors will not work up front because they are to tall. (6+")

I cant seem to find the kind of rotors that are shown in the pics in this thread.

I like how they are bolted to the hub allowing the use of the spindle bolts for caliper brackets

I am using gmc military axles for my current build cause i had them any being scared off by the rotation issue i can tell you all that is required is to remove third member and reinstall on the cover and the cover on the third member side reinstall axles and ur done if ur ambitious switch knuckles and done rotation is correct no grinding or cutting and you have ccw rotation and the diff is moved to driver side easy breazy man if they break i'll replace with rockwells but they are free so i'm gonna find out what happens when they meet 16r20 xl's

Have u actually made the swap yet? Everything I read said that u needed to cut the splines a little longer on one of the shafts for it to fit into the third member. Just wondering, cause I have a set in the back yard I need to make the swap on also.

Have u actually made the swap yet? Everything I read said that u needed to cut the splines a little longer on one of the shafts for it to fit into the third member. Just wondering, cause I have a set in the back yard I need to make the swap on also.


you're talking about flipping the chunk only, to keep it passenger drop.

if you want it drivers drop.... this is the best way to explain it....

pull the chunk and diff cover. then spin the housing around, so the "front" is now facing the "rear" and the chunk side is on the passenger side. now re-install the chunk in the new rear and diff cover on the new front. then swap the knuckles from left to right and you're done. no cutting or grinding.

according to someone else....

there are 3 type of GMC face loaders one has 1 5/8" 10 spline not sure of gear ratio then there is an 1 3/4" 10 spline with 6.67 gears, and there is a 1 3/4" 27 spline version with 6.17 gears the fine spliners should have a loop on the end of the rear shafts.

however... mine are 6.17's with the 27 splines and a 1 5/8" shaft. although, that guy said he was measuring on the splines. i measured the shaft on mine.

i have a set i'm fixing to beat on pretty good. we'll see what happens.

Yeah, that is the way I was planning on doing it, just switching sides with the third member and diff cover. I will have to just give it a shot and see how it works out. Thanks.