Front Right Axel Broke

Power divider should rarely be used in my opinion and never at highway speeds. The gears that drive it if you seen them you would know how delicate they are, and would understand the limited use. Heavy hauling is very common to break an axle in this condition, takin off too fast, mud, pot holes, driver abuse. More than likely if axle is broken it is driver error, things happen, right it's off as lesson learned and try again.

 

axle shafts don't wear out. it takes a shock load to break them

 

I have seen trucks sling drive shafts and break the power divider driven on hard road with P/D locked and have never read anything that said that's OK. Have been around a 32 wheeler that grossed up to 175,000, but never drove it over the road. Instructions were to lock the P/D in and use the lowest gear when taking off and unlock the P/D after rolling. That helps distribute the torque over all axles and prevent breakage. Axle breakage is normally from shock loads but could have been previously fractured and you broke the last straw. Axles that were previously fractured would have different colored metal at the fracture if its all the same color its all on you. If you drove the truck with the broken axle and P/D locked the scrap iron from the axle probably destroyed the differential. Driving with a broken axle could make it difficult to determine the cause

 

Good info on how power dividers work. https://www.teamrunsmart.com/mobile/995357bb-51e0-4bab-815b-d95bd4fc8471/articles

 

I can't be certain you did this, but with you saying "it seemed as if the truck was on ice", sounds to me like you might have actuated the power divider while one of your tire sets were spinning. From a stop, I find it hard to comprehend how you can't tell if you're loosing traction on ice or slick pavement. The word "seemed" indicates this 'confusion'.

If you were on the fuel while switching IAD (power divider) on, along with a rear tireset spinning, that would make for a 'perfect storm' of shock loading the front axle as well as destoying the IAD. How far was it driven from that rest area to the terminal/shop?

I disagree with BoxCarKidd, in that the IAD can be driven while engaged at most any speed, as long as your front axle and rear axle tire diameters are the same. Naturally, having the IAD engaged is not needed, nor advisable, if the road conditions are not slick, but it will not cause damage if engaged properly (wheel not spinning). The act of simply driving with the IAD locked (if not damaged initially) did not cause the broken axle or front differential to come apart.

I'd feel confident in saying the very first damage was the axle due to shock load of some type, whether it was caused by you when first engaging the IAD or a past shock load from another driver. Then the front differential got launched, likely due to because the broken axle now acts like a "free-spinning" right hand wheel, and with the IAD engaged all those miles, it causes that front differential to spin/work beyond its normal limitations.

 

Wow, breaking axle shafts, haven't heard of that in a while. Like others say, I doubt it was your fault. While heavy loads in themselves shouldn't break an axle, HOW it's driven with those loads certainly can. Like KW sez, unless you engaged the PDL while differential was spinning, probably pieces of the axle got in there. There's no room for extra pieces. Many years ago, I believe, that's why they had chain drive trucks, because axles weren't strong enough then, but that shouldn't happen now.

 

When getting to leave it seemed as if the truck was on ice and would not move unless I engaged the power divider. When I got back we took the truck in. sounds to me like it broke before he engaged the pdl. if an open front diff goes out the only way to move the truck is to engage the pdl, but even then its not like driving normally with pdl engaged, because remember the front diff is busted, so it cannot transfer power to that axles drive wheels. not your fault, imo

 

herbiemin,,

Very possible. Good catch! The whole crux of the matter (that the OP didn't say) is WAS the truck actually spinning on iced pavement or not?
Because the OP said the word ice, I assumed there actually was ice under his/her wheels. That may not have been the case.

I agree with ya... if ice was actually not the case, then definitely the axle broke first, and the truck won't move without engaging the power divider (IAD).
So the OP may not have been at fault for breaking the axle, but in any situ where the truck won't drive without the IAD engaged (on good pavement) that's a huge sign not to drive the truck, as there's obviously either a broken axle, broken mid-shaft, or broken differential... somewhere... that needs to be fixed before driving.