Info needed on clutch replacement 2000 century class

I have a 2000 century class with an N14 and a Rockwell trans. It has 670k on the odometer and for the last 5 years (not sure of the miles) it has been used as a box truck for mostlyb light duty cross country hauling. I am in the process of converting its 18ft box into an RV. I'm very comfortable driving the truck and I have taken it on a handful of road trips so I have grown accustomed to the large amount of force it takes to depress its mechanical clutch. Today I was driving it and I depressed the clutch and I felt a sort of snap and then it went to the floor. Fortunately it still grabs and behave seemingly well (good enough that I can move it with the parking brake on). It just has way way less force. So I inspected everything and the linkage is fine but then on the third look I noticed a clean break on the circumference of the spring plate (see center of picture). I believe this is a problem and will require replacement of the clutch is this correct? I would like to do the work myself. I have rebuilt transmissions and replaced clutches before but never on a hd truck. Is there anything special here other than managing the heavy weight of the tranny?

From what I can see the tranny hangs from the bell housing. So, i believe that all I would need to do is support the transmission- remove the u joint on the drive shaft, shifter linkage, and unbolt the bell housing. Then just slide the tranny back and unbolt the clutch. Is there anything special here that I am missing? Special tools or is it an absolute pain to get lined up on the shaft when your sliding it back in? What cost am I looking at for this clutch I can't really find anything online. There is a dealer right nearby so I'll msot likely buy it from them but it would be nice to have a heads up on the sticker shock!

 

Thanks for the advice so far guys. I'm prly going to give the dealer near me a call and see what they charge for the clutch and then ask about labor cause if it isn't ridiculous I would consider it. I'm pretty sure I could do this on my own and that is probably what I will end up doing but not having a good shop to work on this at and my lack of time lately makes me not so excited about it. NASRIZA please give whatever advice you have. How long do you think it will take? I'm thinking most of a day but I don't know. I replaced the clutch in my old jeep in about an hour but that tranny was a lot easier to move around. I will def make sure to purchase the tranny brake when I do it. PABLO I def follow what your saying with the light load, it makes sense. I noticed that in higher gears i could get it to slip if i hit the gas hard.

FYI this is the truck

 

Okay, well I'm gonna ask around because I know a couple people that I think may have a suitable tranny jack. The BIG question I have for you now is what could of caused this? If it was something I did I would really like to know. I could see wearing out a clutch if I was hauling big heavy loads and dropping it hard or maybe grinding and causing it to jump but this is basically just a bobtail rig - I don't understand what caused this to happen. I don't grind ever and shift very smoothly, I don't sit on the clutch ever. For a spring to fail within its operating range I think fatigue but it is still odd to me given what I know these are designed for. I mean even if I really go hard on it that shouldn't be significant compared to somebody hauling a full tanker driving through hills. I can deal with it once but if this happens again I'll be pretty upset / dissappointed.

Some other questions on doing it myself
- do you have torque specs for the sequence on the clutch or are they readily available?
- What about torque specs on the bell housing?
- How difficult are these to slide of off / on to the input shaft. If it is properly supported and lined up will it go pretty easily (ie can it be done by hand). I'm just thinking it can be hard enough to slide a tranny on when weight is negligible but I imagine it is pretty tricky to move 2500 lbs back and forth on the jack. Any tricks their (ratchet strap, bottle jack - thinking out loud)

I know odds are against me here but I have never in my life (i am only 23) paid for work to be done on any of my cars, trucks, boats, planes (I have way to many toys and projects) and everything in between and I really don't want to start. I take on these kinds of projects because I like challenging myself and learning new things turning a wrench. If I paid someone to do it I'd be disappointed that I couldn't be in the garage getting my hands dirty and tearing it apart, seeing how it works. This isn't a road truck and it is still in construction phase so I'm not losing money or opportunity with it sitting here and if it takes a couple weekends to get it done so be it. I just don't want to make a bigger problem or get hurt doing it.