Well my fuel shut off solenoid has went out and before I have even had time to get it fixed I have lost 5th gear (for the second time)!! I am gettin pretty frustrated right now, almost enough to sell the truck but I like it too much. So anyway I picked up the upgraded nut and washer today, which is what I put in last time too. I have no intentions of tearing everything back apart after I get it fixed this time. I plan on tack welding the nut to the shaft this time. Are there any downsides to this? I realize that it would make it difficult to get off should I ever need to do so, but i just plan on making four equally spaced tacks so they could be ground and broke loose should need be. Could this throw anything out of balance? I don't plan on making any huge messy welds, just 4 small neat tacks. I don't see that this would hurt anything just wanted some opinions from some people that are much more knowledgeable than I am. Thanks in advance. Oh and by the way I paid $80 for the nut. I about hit the floor when they quoted that price to me. I thought it was much less last time I bought it. Does this sound high?

 

I loc-tite, staked and welded my "updated nut" after the second time it pooped out.

 

I lost mine twice, luckily the guy that did the work garaunteed it wouldn't come off again. So he fixed it again, after less than 50 miles. The second time he put the upgraded nut on and put the old one on behind it and put loc tite or something similar on it. I have put several thousand miles on it now. I too thought about having him tack weld it, but was told it was not a good idea. Though if you do tack weld it ground the nut and not the mainshaft. I was told that welding it would degrade the strength of the mainshaft. I feel your pain though.

 

Just thinking here, why not a splined washer that goes between gear and nut that has tabs on it, Fold the tabs over the 4 slots in the nut. Could even tack them if neccesary. Or broach a key seat into the shaft in the threaded area, and do a nut/lock washer/jam nut setup like on a 4by front end.

Maybe its time for a set of custom double helical or herringbone gears. No more thrust on accell/decell, wouldn't even need a nut since they self center.

 

i placed two solid tack welds 180 degrees apart on the nut/mainshaft. if u still have ur other 5th gear nut put both them on and weld the 5th gear nut to the other one.

heres a thread with some pics i did for welding the 5th gear nut on
https://www.dieseltruckresource.com/...th+gear+welded

 

Thanks so much for the replies. Got everything tore apart tonight. I am going to go to a dealership in the morning where the diesel mechanic will hopefully let me borrow his tools to fit the nut and the splines on the mainshaft. At least he let me borrow them last time. Anyway, Box 5, that is exaxtly how I was thinking of welding it in. Does anyone else think this will weaken the mainshaft? I definately don't want to do that.

 

I have been pushing a pile of hp at mine and it is welded. The last dyno i was on I did 587/1264 and that was before the twins and nitrous. (not braggin just saying).

If you were to burn a weld into the shaft, yes, it would make the it brittle but a few tack welds wont create enough heat to affect anything. The idea of the tack weld it to negate the ability of the nut to become loose and then be walked back and forth until it falls off.Even if the tack weld didnt stop the nut from retaining its torque the booger on the threads would stop it from unthreading. Just my theory, not to be taken as gospel.

 

A tack weld is NOT going to affect the strength of the shaft. It will only affect a tiny area right in the vicinity of the tack, probably only 1/8" max all the way around the tack. I'd say tack that baby up and be rid of your worries!

 

A tack weld is NOT going to affect the strength of the shaft. It will only affect a tiny area right in the vicinity of the tack, probably only 1/8" max all the way around the tack. I'd say tack that baby up and be rid of your worries!

 

A tack weld is NOT going to affect the strength of the shaft. It will only affect a tiny area right in the vicinity of the tack, probably only 1/8" max all the way around the tack. I'd say tack that baby up and be rid of your worries!

 

What he said (3 times)

 

Three times is all of the reassurance I need!! Hopefully I will get it fixed and back on the road tomorrow. Or today I guess seein as it is 1:30 AM. Thanks so much for all of your help! I really appreciate it. Now if I can only get that dang fuel shut off selonoid fixed!

 

Don't mean to intruce on your thread but maybe I can ax a couple of questions.

I too lost my fifth gear riught at 230 000km . JUst like every other 5 speed owner out there.

My question is. Can you weld the nut on with the tranny still in the truck?

Once it is welded, will it ever be possible to remove the nut? Won't the threads be bunged up forever then?

 

do what box5 did and be done with it.

 

I plan on leavin the tranny in the truck to weld it. I know you can put the nut back on with it in the truck and if I remember right there was plenty of room to weld it. But I plan on doing it today so I will post up and let you know something.