I guess I'll play since I will be the only one to have successfully broken a NV5600HD transmission (6spd manual) without towing.

lets see...my truck has been broke and fixed quite a few times, but the trans left it broke the longest for sure. So I had just fixed the damn thing after blowing up my hx40/35 hybrid turbo by installing the twins its running now. blowing up turbos is another story for another time lol... I've blown up more than one...

so just got the twins on and about a month later, I was driving home and going over tiger mountain on SR-18 which is a 6% grade...there was a slow semi in front of me, and i was still pretty excited about my new found power...

so while already doing 50mph in 6th gear, I bump my truck up to full power on the control monitor and put the skinny pedal to the floor...turbos hit 65psi of boost in less than a second and BOOM! not going forward anymore....try downshifting to 5th....WTF its not there?!!! (meanwhile transmission is making horrible grinding sounds)

So I try for 4th and had to grind it into gear for it to take it because the synchros were toast at this point for it. got it in 4th and regained forward momentum to continue the hill climb and pulled over at the top of the mountain to inspect the damage...even in neutral with the engine running it was grinding... saw that the case was still intact and wasn't leaking anything, so I drove it the rest of the way home, and parked it for a year.

Literally ripped every single tooth off of the gear and broke the intermediate shaft. surprised the input shaft didn't break, but apparently it is stronger than 5th and 6th gears were...

on my second NV5600 now and a step up from mine...this one has the larger input shaft and built slightly stronger than mine. also added trans coolers and a temp probe to make sure it doesn't get too hot. running amsoil in it now and have it overfilled quite a bit. should last much longer now and haven't had an issue with it since, even with full power runs in 6th. I have backed off the aggressiveness of my tuning though to make power come in smoother and not slam in as hard as it did.



carnage:





can't really tell from the pic, but that last one: the input shaft bearings were toast and had a ton of slop allowing the shafts to move apart which is what I believe caused the chain reaction of destruction...shaft starts to flex from the torque and pulls away enough to get at the edge of the teeth and starts ripping teeth off the gears till it binds and breaks the shaft... putting over double the torque this trans was rated for through it is a bit harsh on it lol...

also, I was not shifting, and was not towing or hauling weight.. truck was empty and already been in 6th gear for a while. I simply just put the skinny pedal to the floor and the engine torque did the rest.

 

Wow jigabop, I think you have all of us beat!

 

I dunno...that busted xfer case looked like game over no driving home lol..mine was still drivable, I just had no 5th or 6th gear and it make nasty grinding sounds.

it just sat for a year because I had to scrape together $3000 to get a rebuilt trans. I did the swap myself though.

 

Oh ok. Dlyter09 still tops all.

 

NV4500 leaked itself dry. Completely seized up, no movement in any gear, neutral was seized as well. Had to remove drive shaft to tow home. November '11.










NP241 Case failure. Vibrations from the front driveline to blame.

 

Wow Wombat...

 

Wombat wins in my book. Dang, that thing is Arizona baked in the sun bone dry. It is a miracle it lasted that long.

 

Well we'll just have to have a poll after a this thread grows a little more!

 

Wombat just had to try and fit in lol

 

lol. Wombat wins by neglect...leaking a trans dry...operator error...

known vibration from front driveline: again neglect and operator error... tcase cracking and sheering off... crap tcase not driver error... and trans sheering gears...combo of weak parts and driver error for massively exceeding transmissions rated power lol