Engine/Transmission (1998.5 - 2002) NV5600 problems (kinda long)

[DrewGzy]

NV5600 problems (Upadate:too much power???)

I think that 6th gear is damaged in some way.



I swapped the six speed in maybe two months ago. I have put on around 3000 miles on it. Before this weekend I did not tow anything with the new transmission. I went on an 800 mile trip with a 7500 lb trailer. Around 600 miles into the trip I was doing 70 or so in sixth gear and the truck started making a knocking noise, at first I thought it was something in the engine, it sounded like something was hitting the fan. After I pulled over and checked out some things the noise was obviously in the transmission/clutch. The noise would go away with the clutch in. I decided to go ahead and drive it at least to the next town. When I got going the noise was present but not very loud, until I went into sixth, then it would get very loud and the entire truck would vibrate, so I drove the rest of the way in fifth. I ended up driving the rest of the 200 miles in fifth gear, and the noise never got worse.



Unfortunately I don't know the history of the transmission, it has the bigger input shaft, and it was rebuilt by a local shop. The only thing I do know is that fourth gear was replaced as part of the rebuild. I ran Redline MTL in the transmission, and the transmission is under warranty from the transmission shop.



I am just curious what everyone thought, I figure that sixth gear was fatigued before I got it and it was ready to go out.



It kind of sucked that I swapped out a perfectly good five speed, because I was worried about losing fifth gear, and now this.





Update:

transmission was disassembled by the shop that had rebuilt it in the first place, sixth gear had several damaged teeth, and three of the teeth were broken off. The broken pieces fell down and messed up first gear on the main shaft and the "cluster. "



The person I have been dealing with at the transmission shop thinks that too much power caused the problem, I would not have a problem believing this except this was the first time towing with the transmission, and I was not being hard on it, and my truck is not building the boost that I think I should with my modifications (26 PSI max. )



Any opinions on this would be appreciated; how much power is too much for this transmission? Should I worry about it failing again?



Thanks

 

[DrewGzy]

TTT:



Updated

 

[DHayden]

I don't know what your mods are, you can see mine in my sig. I have pulled an 18k trailer cross country a few times, across the rockies in 6th gear most of the way. Only used 5th a few times for curvy roads and once for coolant temp but I never had a problem.



I have never dynoed my truck but I think I would lay down some reasonable numbers. Their are many with more HP than me and these 6spds stand up to it very well.



The jist is that I think they are blowing some smoke up "your you know where" so they can make it seem like its your fault. Though you dont know what kind of power the guy was putting to it before you. At any rate when they did the rebuild they should have checked for stress fractures. Maybe not, but if I was guaranteeing it I know I would.

 

[Gary - K7GLD]

I would toss the "too much HP" balony, other than what might have occured prior to your installation - guys pull VERY heavy weights in RVing regularly with these trannies without failure - and a goodly representation of them have serious Bombs installed...



Maybe you got one of Sledpullers castoff trannies...

 

[DrewGzy]

The transmission shop is cool with it, it was a used transmission and they are taking care of it.



My mods are in my signature, I was told to expect around 450 horsepower, I'm not sure if that is true or not, I have not dynoed it.



So what I am running should be fine with the NV5600??





Thanks again

 

[jarsong]

Originally posted by DrewGzy

The transmission shop is cool with it, it was a used transmission and they are taking care of it.



My mods are in my signature, I was told to expect around 450 horsepower, I'm not sure if that is true or not, I have not dynoed it.



So what I am running should be fine with the NV5600??





Thanks again

450 horsepower? No problem. On the street it should just smile at you. I would imagine you would break a U-joint/yoke or pinion before you hurt the trans.

jarsong