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NV4500 fifth gear nut

Posted By: 6PakBee

NV4500 fifth gear nut - 02/19/23 08:52 PM

I lost fifth gear in my '98 Cummins. I bought the nut kit that has the two small setscrews and the brass pucks. No instructions. I guess the brass pucks go in the holes first but is there a torque on the setscrews? I also bought the retainer that has the four "fingers" that fit into the nut. Anyone have any experience with this piece?
Posted By: Rhinodart

Re: NV4500 fifth gear nut - 02/19/23 09:10 PM

No experience rebuilding but I went through 7 of those damn transmissions because of that nut! The last 3 had the fix to keep it from backing out, didn't freakin' work! mad
Posted By: Hugh Jorgan

Re: NV4500 fifth gear nut - 02/19/23 09:32 PM

Is there anything on youtube? shruggy
Posted By: Guitar Jones

Re: NV4500 fifth gear nut - 02/19/23 11:51 PM

I don't have any experience with those kits, but I do know it is really only a problem with the Cummins trucks, gas trucks don't do it. Must be something about the harmonics in the Cummins that knocks the nut loose.
Posted By: Guitar Jones

Re: NV4500 fifth gear nut - 02/19/23 11:55 PM

Originally Posted by 6PakBee
I lost fifth gear in my '98 Cummins. I bought the nut kit that has the two small setscrews and the brass pucks. No instructions. I guess the brass pucks go in the holes first but is there a torque on the setscrews? I also bought the retainer that has the four "fingers" that fit into the nut. Anyone have any experience with this piece?

Torque King has instructual videos on you tube.
Posted By: NITROUSN

Re: NV4500 fifth gear nut - 02/20/23 01:57 AM

Originally Posted by 6PakBee
I lost fifth gear in my '98 Cummins. I bought the nut kit that has the two small setscrews and the brass pucks. No instructions. I guess the brass pucks go in the holes first but is there a torque on the setscrews? I also bought the retainer that has the four "fingers" that fit into the nut. Anyone have any experience with this piece?


You bought a kit and they did not show instructions? Send it back. Just google the 5th gear nut. That fix is garbage.
Posted By: NITROUSN

Re: NV4500 fifth gear nut - 02/20/23 02:08 AM

You need the special nut wrench to properly torque the nut. https://torqueking.com/nv4500-5th-gear-failures-and-solutions/
Posted By: 6PakBee

Re: NV4500 fifth gear nut - 02/20/23 04:08 AM

Originally Posted by NITROUSN
You need the special nut wrench to properly torque the nut. https://torqueking.com/nv4500-5th-gear-failures-and-solutions/


I bought both special tools, the spanner for the nut and the splined holder for the shaft. The reason I asked the question on this forum is that typically people who respond are more responsible when repairing equipment. What I saw on line were people using the wrong sealant on the transmission extension housing and tightening the gear nut with a hammer and chisel. So people who went on and on about their 3rd, 4th, 5th failure....I don't know if they knew what they were doing or they were just following the YouTube "mechanics".
Posted By: NITROUSN

Re: NV4500 fifth gear nut - 02/20/23 02:32 PM

Clean it well, red loctite, new nut and this lock ring.Lock
Posted By: 6PakBee

Re: NV4500 fifth gear nut - 02/20/23 03:23 PM

Originally Posted by NITROUSN
Clean it well, red loctite, new nut and this lock ring.Lock


I have that lock ring as well. As to the Loctite, I'm looking at 648 for the splines on the gear and 263 for the nut.
Posted By: max_maniac

Re: NV4500 fifth gear nut - 02/21/23 02:44 AM

Give Dan Brewer a call and he can tell you how to fix it!
Posted By: 6PakBee

Re: NV4500 fifth gear nut - 02/26/23 02:07 PM

Well, put 5th gear together last night. After more than one email with the Loctite tech line, settled on 648 for the gear and 277 for the nut. Initially torqued it to 250 lb-ft (that's all the torque wrench I have) as the factory specification is 250-300 ft-lbs. I then used a breaker bar and a cheater and torqued the living bejesus out of the nut. So I have a new gear, new nut with the two set screws, and the pronged retainer. We'll see how this works out.
luck
Posted By: moparx

Re: NV4500 fifth gear nut - 02/26/23 03:19 PM

and as a very last resort, break out the welder for two big tacks. whistling boogie
hackery at it's finest ! biggrin
beer
Posted By: J_BODY

Re: NV4500 fifth gear nut - 03/01/23 01:20 AM

Originally Posted by moparx
and as a very last resort, break out the welder for two big tacks. whistling boogie
hackery at it's finest ! biggrin
beer


I’ve seen that broken…..
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