Well was messing around in the middle of nowhere tonight racing a buddy,and when i hit about 137mph according to my logs my truck upshifted into overdrive and holy hell broke loose driveshaft snapped in 2 about 6 in before tailshaft for rear diff.My freind who was behind me said it looked like the 4th of july.Truck is fine, my pride is hurt had to be towed by a dodge.And will look at sponsars on main page for a real driveshaft, and maybe some driveshaft loops.I think i read long ago about naked av having this issue but he had aluminum shaft and mine was steel so wasnt worried .

 

Dont know where you are located but PM for the the shop that is doing mine now.

BTW, you are lucky in many ways my friend.

 

Holy Potential Polevault, Batman - glad you're okay.

Mine came apart at 141 mph, thank God it was on the dyno.

I have a couple of suggestions - PM sent.

 

Glad your OK! That could of easily of been the end!

 

Damn I didnt know a driveshaft could break like that. I guess going at that speed a stock shaft isn't made to handle that much force. Good nothing worse happend!

 

Count your lucky stars, my man.

 

Thx for the tips,Naked and Brian i sent yu a pm.YA i thank my lucky starz it did not snap coming off the tcase, cause i think i would not be writing this.My mod list is not current but the radix was still pulling when it broke, i have allways left in in drive unless im on interstate and have never ran that fast, kissed 120 a ton when i used to spray it.I had a freind say it broke cause of the sudden change in rpm at that speed when it upshifted into od sounds plausible but what do i know.

 

If you search hard enough you are probably gonna find that denny's driveshafts are pretty damn reputable. At 140 MPH (OMG) yuor critical speed of that shaft is on another planet. The only reason you probably didn't pole vault in some form was that the speed was so great it just thrashed that stock aluminum paper thin shaft. That's what avalanches have right? When you upgrade to heavy shaft make sure you get as a big as diameter as you can. (4" is the biggest I believe and denny's only sells up to 3") Good luck and glad to see your alive to tell of the mishap. Just remember critical speed...when researching.

 

When I talked to Denny's they said they would not be able to make me what I needed for less than a couple hundred over what the OEM shaft would cost me, and it would not be better in either quality or strength over the OEM unit.

The Avalanche driveshaft is 72" long and 5" in diameter. It is crazy long for a one-piece driveshaft and very strong for aluminum because of its diameter....the only thing stronger that would be safer would be a 2-piece chromoly driveshaft. Of course, this would entail mounting a new crossmember, and once it was running, you would suffer lots of parasitic loss from the extra joint and extra weight of the steel over the aluminum.

After a shitload of research, I ended up going with another OEM driveshaft, but got it balanced at a driveline shop here in town. Stock, it came quite a bit out of alignment, which could certainly cause some problems. Pretty much everyone told me (Denny's, Inland Empire Driveline here in California, other places...) that the best bet because of my requirements was an OEM unit, properly balanced.

 

I have my new one installed (steel) and it is flawless. The OEM Alum 5 inch D/S had .040 of runout, in the time I drove on it (18K) it damaged the tailshaft seal on the trans and caused it to leak. If you are looking for a good driveline shop in SoCal, I highly Reccomend Coast Driveline in Ventura.

FYI, I could not go over 90 with the stock drivshaft without getting massive vibration. On the way home tonight I got it up to 125 and it felt like a Benz.