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6th gear loose??

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mechanic told me that the 6th gear in the dodge trannys can become loose and need to be tightened down. said the industry is having problems w/em. is this true?
 
He probably does not know the product well enough to knowthat it is the NV4500 5 speed that has the problems. 5th gear is outside the the main case in the tailhousing on the output shaft. It is held on by a nut that is very prone to backing off and thus the gear slides off and you lose 5th gear. There are many companies with fixes for this problem.



The G56 and NV5600 both have 6th gear inside the main case. No where for it to go, nothing to to tighten.
 
went to a specialty 4x4 place today. they drove it, said that feels like 6th gear is loose on the shaft or a bushing is going out. he called a trans. shop in san antonio, guy there said he sees a number of these trannys w/this problem and keeps rebuilt ones on the shelf. bottom line, $3500 for a transmission, $400 to take out /put in. he keeps my core. is this problem real or common? when i shift into 6th i can feel a vibration thru the shifter. the harder you pull down in to 6th the worse it gets. i need some advice here bad! thanks
 
You may have internal damage or bearings that are worn very badly, how is the oil level and condition? As you can see from the attached picture there is not a lot of room for 6th gear to go anywhere. The normal problem with a NV5600 is the syncros - hard shifting/hard to get into gear/grinding while shifting/etc is what most fuss about.
 
I just got my truck back today from the shop.



They replaced the sixth gear and a bearing, along with a few other things. (I'm not sure what else because I picked it up late and didn't get a chance to talk to the advisor or mechanic).



This all because I went to pass someone about 3 and a half weeks ago and lost sixth - she just made a "bang" and nothing - like it was in neutral. Totally gone. Had to drive her home in fifth about 100 miles.



I ran Redline MT fluid, with about half a quart extra due to towing in the mountains. It was fairly fresh fluid (changed somewhere around 40K and I have 53K on it).



Anyway, I'm a sixth gear looser :rolleyes:.



Wayne
 
Gear problems don't seem very common in the NV5600 but it does have some weaknesses. Supposedly the pocket bearing between the input & output shafts can be overstressed, due to the length of the shafts there isn't enough support along the entire length and when you start fueling it hard the shafts start to flex apart from each other and overstresses the bearing.
 
thats kinda what happened to me too. was trying to keep up w/traffic in austin and hit 80mph and heard a noise and felt a vibration and backed off and soon after this 6th gear problem started. i haven't run this truck hard at all. maybe 500 towing miles (20' boat) and the rest easy highway miles.
 
Actually, there was a thread here a while ago about 6th gears...

They tend to remove the splines from the output shaft from the jackhammer effect of the cummins, the same vibration that loosens the NV4500's 5th gear nut. This typically happens to heavily loaded trucks that tow a lot...
 
found out the shaft was borken in two and the only thing holding the thing together was the clutch pressure. all this according to the transmission shop guy. says it is clear from looking at shaft breaking point that it is defective casting. he called in a professor of metalurgy from the university of texas at san marcos and he agrees. anyway... bill is $3100 as needed clutch and parts too. anyone else heard of this happening?
 
Mine's making lots of noise in sixth gear after a couple hundred miles of "ticking" in sixth only. Are the dealers taking care of this? I've only got 50k on the thing. It does tow heavy most of the time.
 
Mine's making lots of noise in sixth gear after a couple hundred miles of "ticking" in sixth only. Are the dealers taking care of this? I've only got 50k on the thing. It does tow heavy most of the time.



Towing heavy in 6th some people say is hard on them



I don't know what the dealer would do, they don't use/make the NV5600 anymore
 
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