Stock axle strength?

[Pat]

Just curious, how strong is the stock rear axle? IF I ever get my wagon done & a 360 in it, do I HAVE TO replace the rear axle even if I don't plan on beating on it? No burnouts, etc., just drive it normally?

[midtownboarder]

you should be alright, a d35 axle can handle a decent amount of torque as along as you aren't purposely being hard on it...

[captspillane]

Seriously, how long do you think you'll manage to behave with the performance Eagle that you've lusted for most of your life? If you don't plan on stomping on it, why bother making it? The project isn't properly finished until the entire drivetrain complements the engine.

The stock axle won't self destruct immediately, but it will be very fragile. I've broken three axles over the years with the stock engine. They are not a Dana35, they are Dana 35 center castings with teensy little axle tubes and tiny little axle shafts with hubs gently splined at the end. Its called an AMC 15. A real Dana 35 has considerably thicker axle tubes and one piece axle shafts. When the axle tube is thin, it puts much more stress on the axle. All of mine broke because my family consistantly put the weight of the vehicle on to two tires, which bends the axle at the same time it has torque applied. They do not forgive that treatment.

I wouldn't worry too much about the front axle. An Independent Front Suspension is inherently a full floating axle, where the axle only has torsion stress but no shear stress applied. It will outlast most rear axles because of the torque split at the transfer case (Most have a torque bias to the rear axle) and because the flanged rear axles bear vehicle weight as well as suffer the torque of the engine.

In my case I plan on towing with it. The increased engine torque along with the increased weight on the axle is a deadly combination. I cannot afford to keep the stock axle even if I am gentle with it.

-The stock AMC 15 is poor. It's a great match to an Iron Duke 4 cylinder with 80 HP.
-An XJ axle, Dana 35 or Chysler 8.25, is good. It's a great match for a 258 at 115 HP, and an okay match to the 4.0.
-A Ford Explorer axle is better than a Dana 35 but not quite as good as a Dana 44.
-A Dana44 from a Cherokee or Commanche is great. It's a great match to a 4.0 at 190 HP and a good match to a stock 360.
-A modified Dana 44 from a Scout or J10 truck is slightly better than the XJ or MJ Dana 44, but much harder to fit under an Eagle.
-A flanged semi floating 5 lug Dana 60 from a J10 truck is great. It's the axle going behind my AMC 401 at 435 HP. I will also be upgrading the front axle on that SX4 in the near future.
-A full floating 6 lug Dana 60 from a J20 truck is overkill. It's too heavy and only worthwhile if you're going to tow a larger amount than is legally allowed with an Eagle.

[Pat]

Thanks, Have read about replacing it with a Jeep axle (couldn't remember which one). Know there's something about the shock mounting needing cut off & welded on differently. Am I correct there is NO 'direct' bolt-in?

[midtownboarder]

whoops, my bad...i called it a d35 because of the center (i'm used to talking xj stuff). there is a difference in xj d35 axles though...from 84-89 they used a d35 non c-clip axle, and 90-01 were c-clip axles. chrysler 8.25 axles are also c-clip. i would steer clear of the c-clip axles if you can, they are less fun to deal with if you break one. an xj d44 is a pretty stout axle, its what i run in my xj with 35" tires and a locker...i've wheeled it pretty hard and have yet to break it, but unfortunately they are harder to find. ford 8.8's are easy to find, but they are also a little narrower than a d35/44...

[captspillane]

I'm not convinced that's true, but I haven't tried yet. The XJ axles have perches the correct width and two shock mounts, one on either side of the axle. The Eagle axle has both shocks on the same side of the axle. Typically the XJ shock mounts are cut off and Eagle ones welded on. I believe this isn't totally necessary if your Eagle is higher than stock, because the top of the shock mount is in the center above the axle. It's plausible to bolt on an XJ axle and use the XJ shock mounts as is.

The problem is that putting the shock on the opposite side usually interferes with the exhaust pipe. It also gets very close to the gas tank. At stock height I believe its too much going on to easily fit, but it might work with slightly stiffer leaf springs. The Eagle shocks will mate with the XJ shock mounts, but I also don't know if they need to be a different length to work. I may need to measure the new travel of the shocks and order a set to those specs.

A Commanche Dana 44 is cheaper and much easier to find than an XJ version. Its more common to find those with a factory limited slip. Those don't have shock mounts and the perch is on the underside. Those must have new perches and shock mounts welded on. I paid $300 for the Commanche Dana 44 with LSD and $350 for the XJ Dana 44.

In any case welding shock mounts and even perches isn't that big of a deal.

[carnuck]

Seriously, how long do you think you'll manage to behave with the performance Eagle that you've lusted for most of your life? If you don't plan on stomping on it, why bother making it? The project isn't properly finished until the entire drivetrain complements the engine.

The stock axle won't self destruct immediately, but it will be very fragile. I've broken three axles over the years with the stock engine. They are not a Dana35, they are Dana 35 center castings with teensy little axle tubes and tiny little axle shafts with hubs gently splined at the end. Its called an AMC 15. A real Dana 35 has considerably thicker axle tubes and one piece axle shafts. When the axle tube is thin, it puts much more stress on the axle. All of mine broke because my family consistantly put the weight of the vehicle on to two tires, which bends the axle at the same time it has torque applied. They do not forgive that treatment.

I wouldn't worry too much about the front axle. An Independent Front Suspension is inherently a full floating axle, where the axle only has torsion stress but no shear stress applied. It will outlast most rear axles because of the torque split at the transfer case (Most have a torque bias to the rear axle) and because the flanged rear axles bear vehicle weight as well as suffer the torque of the engine.

In my case I plan on towing with it. The increased engine torque along with the increased weight on the axle is a deadly combination. I cannot afford to keep the stock axle even if I am gentle with it.

-The stock AMC 15 is poor. It's a great match to an Iron Duke 4 cylinder with 80 HP.
-An XJ axle, Dana 35 or Chysler 8.25, is good. It's a great match for a 258 at 115 HP, and an okay match to the 4.0.
-A Ford Explorer axle is better than a Dana 35 but not quite as good as a Dana 44.
-A Dana44 from a Cherokee or Commanche is great. It's a great match to a 4.0 at 190 HP and a good match to a stock 360.
-A modified Dana 44 from a Scout or J10 truck is slightly better than the XJ or MJ Dana 44, but much harder to fit under an Eagle.
-A flanged semi floating 5 lug Dana 60 from a J10 truck is great. It's the axle going behind my AMC 401 at 435 HP. I will also be upgrading the front axle on that SX4 in the near future.
-A full floating 6 lug Dana 60 from a J20 truck is overkill. It's too heavy and only worthwhile if you're going to tow a larger amount than is legally allowed with an Eagle.

I think for the last option you meant J10 pickup (6 lug) as J20 are 8 lug (unless you find my old one I swapped the axles from my J10 into)

[carnuck]

I'm not convinced that's true, but I haven't tried yet. The XJ axles have perches the correct width and two shock mounts, one on either side of the axle. The Eagle axle has both shocks on the same side of the axle. Typically the XJ shock mounts are cut off and Eagle ones welded on. I believe this isn't totally necessary if your Eagle is higher than stock, because the top of the shock mount is in the center above the axle. It's plausible to bolt on an XJ axle and use the XJ shock mounts as is.

The problem is that putting the shock on the opposite side usually interferes with the exhaust pipe. It also gets very close to the gas tank. At stock height I believe its too much going on to easily fit, but it might work with slightly stiffer leaf springs. The Eagle shocks will mate with the XJ shock mounts, but I also don't know if they need to be a different length to work. I may need to measure the new travel of the shocks and order a set to those specs.

A Commanche Dana 44 is cheaper and much easier to find than an XJ version. Its more common to find those with a factory limited slip. Those don't have shock mounts and the perch is on the underside. Those must have new perches and shock mounts welded on. I paid $300 for the Commanche Dana 44 with LSD and $350 for the XJ Dana 44.

In any case welding shock mounts and even perches isn't that big of a deal.

Eagle and XJ shock mounts are opposite to each other

[captspillane]

Yes, I meant 8 lug in that sentence. The 8 lug J20 Dana 60 is full floating, and the 6 lug J20 Dana 60 is flanged semi-floating. There was also a 5 lug flanged Dana 60 found in early Gladiators. My J10 has a 6 lug Dana 44, but there are also 5 lug Jtruck axles out there.

Another possibility is a Warn kit that converted the flanged axle to locking hubs. That aftermarket kit allowed you to have a formerly 6 lug flanged Dana 60 converted to full floating, 5 x 5.5 lug.

[TheWraith]

The Dana 35 and any variant is junk.  It will last awhile as part of a factory powertrain with stock tires.  If you beat on it as part of the factory powertrain it will fail.  Put it behind a V-8 or go to a taller tire and it will not last long at all.  The pinion size is just too small to offer the strength needed to survive.  The Dana 30 is even stronger then the d35.

In the article where the builder performed the 360 engine swap he used a d44 out of a'86 Cherokee and said it was a direct bolt-in.  I haven't looked but I'm sure it would be easy to discern which years the Cherokee was offered with this d44.  Point-in-case the Louisville Ky (nearest one to me) has an '87 Cherokee.  If it is a match to the '86, it would be worth grabbing the rear axle.

There were a few d60 that left the factory as a five lug, but they are hard to find.  Even then it would have a larger bolt pattern, would be much wider, a lot heavier and likely require 16" rims to clear the large break drums.  If you want strength and don't mind the weight penalty it is hard to beat 1-ton parts, but to fit under an Eagle it would have to be narrowed.  The full-floater design makes it easier to accomplish, but fabrication skills are needed.  This is something most any machine shop should be able to accomplish but it will cost.

IMO the d44 or the Ford 8.8 are the best two options.  The 8.8 will be just a little narrower, about an inch IIRC.  It can also be had w/rear disc brakes.  If you don't find the direct-bolt-in d44 version but use a different d44, or if you go with the 8.8, relocating or replacing the brackets is not that difficult if you can weld.

[midtownboarder]

the xj d44 was offered from 87-89 (maybe some 86.5+), and only in xj's with the tow package...

[captspillane]

I'm going to attempt to bolt in my XJ Dana 44 as is. Its not supposed to work but I won't believe that it will or won't until I've attempted it myself. I'll also be doing a disc brake conversion using commonly available ZJ parts. The V8 Grand Cherokees had Dana 44s behind them as well.

The Eagle axle is 61" wide. It puts the tire an obnoxious amount inside the fender well. I dislike it immensely. I have 2 inch spacers on either side in order to put the tire where I want it in relation to the outside of the body. That adds up to a total WMS of 65" that I consider perfect. The J10 truck axles are 67" WMS. That's a two inch difference, which is a reasonable amount to correct with changes in rim backspacing.

Warn came out with a kit that converts a flanged 6 Lug Dana 60 to full floating, 5 lug. I don't know if the kit is still in production.

http://www.jpmagazine.com/techarticles/drivetrain/154_9903_warns_rear_full_floating_dana_60_kit/index.html

J-trucks use 15 inch wheels. The only time you need 16 inch or 17 rims is if you use a mixture of Ford and Chevy dual piston brakes.

My 401 SX4 will have a custom made axle. Those are machined to lighten the casting to comparable weight as a Dana 44, but with the strength of Dana 60 internals. It will have disc brakes. I expect to pay between 5 and 6 grand.

Here are pictures of a stock Eagle axle with two 2" wheel adapters, or a total of four inches added to the width of the axle.


 

[midtownboarder]

I'll also be doing a disc brake conversion using commonly available ZJ parts.

i used kj rear discs...if you can find them they are easier, you don't have to make that little spacer/washer deal...everything else is the same, except you also need to use a tj rubicon axle retainer because it has a lip on it instead of being flat...

[TheWraith]

Warn use to make a kit for the d44 to make it a full floater.  It is no longer in production.  I don't know for sure but due to the asking price I don't think they sold well.  For the off-road community it was cheaper to switch to a d60 or corporate 14 bolt then to add the warn kit to a d44.

I have a buddy that is working on making his own d44 full floater kit using factory front d44 spindles.  Something I'm going to look into if he ever gets it figured out.  Not sure how wide this would end up being.  My rear d44 is out of a Scout.  I'm not sure how wide from wms to wms, but it could stand to be a little wider to match the front d44 (these are under my S-10, not an Eagle).  The next time I get the rear wheels off I'll measure the rear and see how it matches up with the AMC15.

[carnuck]

Don't know if they did it in the US, but in Canada Mopar B bodies with big block and 4 bbl had a D60 semi-float option with the correct pattern 5 lug (not sure on the width) After blowing up a bunch of 8 3/4s with my hemi I found one and didn't have to change anything but gear ratios after that. (then I started turning 727 output shafts into spaghetti!)