5th gear
 

lost it on the way to work this mornin. guess i get to yank my trans out again... whats the best way to fix it n make sure it doesnt happen again?

no need to pull the tranny. dodge sells an updated 5th gear nut. also use b12 and clean it off real well and use locktite. they have an updated output shaft that uses a snap ring after the 5th gear then put the nut on. mine has it and i've towed in 5th gear many times and has never backed off.

there's lots of ways to fix the one you got as well. you can put it back on and then tack some welds behind the nut. also, a transmission guy told me not to spend any money, just tighten the nut back on the gear and then take a punch and give it a couple whacks around the nut where the slits are on the shaft to keep it from ever moving off. good luck man

i did both before i put the transmission in, n yet it still happened. i do tow quite a bit and i never hesitated to throw it in 5th n lean on it, even with a couple tons behind me.... oops:argh:
i realize i dont have to take the transmission out, but i imagine the shaft and nut are jacked up now so i'll probably pull it out and replace stuff.

well glad i sold the one i did lol. guess i eventually would have figured it out. sounds like instead of some tacks, you need to just weld her all the way around :tu:

wouldnt that warp the shaft, or atleast change the temper n weaken it? i dont wanna go breakin anything else...

this truck is still on the road and 5th gear is doig great

https://www.dieselbombers.com/dodge-...ining-nut.html

its hard to get a good weld on the shaft. being coated with oil for so long. I always wondered why they didn't cut left handed threads in the shaft. then instead of backing off itd just get tighter

i dont think its the spinnin as much as it is the low rpm vibration that backs the nut off. it'd prolly do the same even with left handed thread.
n thanks whit

dan at quad4x4 swears by buying the correct nut, not screwing with the factory loctite stuff in it, and torque it correctly. Mine was still as tight as ever when I blew up the other end of the trans after about 10k miles.

which nut? the one with the set screws?

well if you dont have it apart yet it may not have been the nut, mine never moved and had the updated shaft and all it toasted both the gears, peeled all the teeth of them.

Brake parts cleaner (or a paint shop degreaser) and then you weld it all the way around... that's what i did and it's NEVER EVER EVER EVER going to come off..

now if i have to fix anything else in my tranny, that's a whole other story... but i don't think anything else will fail on these trannys...

The easy long term solution is to stop abusing the transmission by lugging it in 5th. I know that's hard to do when the engine will easily make the pull in 5th...

its even harder not to shift into 5th when the truck only runs about 45-50 in 4th.

well i got my truck all tore apart to fix 5th gear, but i hit a snag. the tack welds i put on the first time, are still in place, the nut hasnt moved.... what did i break now???:s:
does anybody have any pics of what it looks like when 5th comes off?
n what kinda tool do i need to get that nut off?

yeah when i pulled mine apart, the nut was still tight. i've got the nut off now but the gear wont come off. i think im gonna drop the trans n pull the shift tower off n see what i can see.
i lost 5th on the way to work a week ago, i had just shifted into 5th, got back into the throttle and POP, no 5th gear, just like neutral but i can hear something grinding or rattling. all the other gears work fine. what else could have happened?

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if i put the truck in 5th, i can grab the output shaft and turn it. the big gear next to it turns also. i can hear a crunching sounds coming from inside the gearbox.

You have 4.10's in that truck? If so, then you may not be abusing the transmission after all. I thought you were lugging it based on something you said in an earlier post. The definition of lugging it as far as I've always heard for these transmissions is applying heavy throttle at or below about 1500 rpm. If you have 3.54's and can't get more than 45 or 50 mph out of 4th, what rpm is that?

if you have all other gears I believe your problem would be on the counter shaft 5th gear assuming the gear on the mainshaft is still on there.

i'm forced to believe they are 4.10's. in 5th at 3100 rpms im doin about 95-100. but i have lugged 5th gear, and i have towed heavy up steep grades in 5th. i dont beat the snot out of it but i do make it work n earn its keep

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yep all the other gears work as usual. it goes into 5th's place in the shift pattern, but no power transfer. how do i go about replacin the counter shaft? am i better off sendin my trans for a core n buyin a new one? i am fairly mechanically inclined and have a heated garage to work in. is this something i can do?

check the cone gear on the countershaft, it is on the back of the transmission the bigger gear on the lower shaft. just take the snapring off the lower shaft and check the internal splines on the gear. i had the same problem with my 96 and thought it was the famous nut but mine actually ripped the internal teeth on the cone gear. if thats the case, call Southern Gear Co. out of georgia. dodge wanted $400 for the gear and i got a new one shipped to me for less than 60 bucks from southern gear. their number is 1-800-289-7432. p.s. the splines will look ok from the outside but under the snap ring is a different story!

thanks for the info. i have the trans on the garage floor with the shift tower n inspection plate off n i cant see anything wrong with it... u wouldnt happen to have any pics of it would ya?

There is a full spline output shaft available for the Nv4500 it is a stronger gear to shaft engagement.The old shafts are only partially splined and weak.

my output shaft is fine. i've narrowed it down to somethin screwed up with the countershaft. is there anything this cummins wont break???

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this was exactly what the problem was. i pulled the snap ring off n pulled the gear and there are no teeth left inside it. the countershaft is fine but the gear is toast. i had the shift tower off the tranny lookin down inside thinkin this is not gonna be fun. thanks again man u saved me alot of hassle

this may help ya
NV4500 Transmission Exploded View

Your welcome. anything i can do to help with a problem i have seen makes me feel needed. im just glad to help. Southern Gear was the cheapest place i could find another gear. one of their techs told me that lugging in fifth would cause that. :tu: