Engine/Transmission (1994 - 1998) Welding Fith Gear Nut

[Dick R]

need a little info from someone that has welded the fith gear nut to the shaft , I have an A. C. stick welder and was wondering what heat range and what rod was used for the best results , if you go to hot things get burnt up and of not enough heat and a person does not get the proper depth , any suggestions would be much appreciated . thanks Dick R

 

[Doubleclutch]

Haven't heard that to be one of the best ways to fix the problem Some of the guys have had short term fixes, but I think the replacement mainshaft is the only long term answer.

Greg

 

[Dick R]

thanks for responding , I did a number of searches and found out quite a few members have been spot welding the nut in place and had good results , I only run accross one individual that had his come off after welding it on but it probably was not a deep enough weld , I do plan one replacing the transmission at a later date with one from Standard or Quad 4x4 because from what I have read when they start getting a number of miles on the transmission it also has other issues and those issues are addressed on the rebuild . thanks Dick R

 

[Dick R]

Anyone , ( HELP ) I have to do this welding in the mourning and any input would much be appreciated I am not the greatest welder but I Know I can do this with a little input from someone whom has done this with success . thanks , CUMMINS ALL THE WAY .

 

[JWHays]

Ya might want to use a 6011 rod at about 110 amps... should get good pen.



... John

 

[KWentling]

I wouldn't do it to mine, but if you must, preheat the shaft to 250* F. before you weld. I don't know the carbon content of this shaft, but this may help to minimize the heat affected zone. Seen too many broken shafts (though not specificaly transmission shafts) that have been welded on cold for me to consider doing it. If the time comes for a fifth gear fix, I will do the fully splined shaft. By the way, I've worked in industrial machine shops as a machinist and welder for 30 years, (we do weld shafts, but only with proper preheat and postheat, usually much higher than 250*F. ) so I might have a clue of what I say. I know some have done this and I haven't heard of one breaking, but this would certainly would not be considered a good practice.

Kim

 

[SRadke]

Like I said in teh other post I don't advise it but if I were going to do it with an AC buzzbox I'd use 3/32" 7018 at about 120 amps. Also just tack it, you're not holding load just keeping it from backing off. Wow, did those words realy come out of the mouth of a guy with a metallurgy degree? Spooky.



-Scott



PS, I don't advise much preheat here. 250° won't hurt anything but if you get much beyond 500° you'll be screwing with the temper of the shaft.

 

[TurboTweaker]

E6011 or E7018, weld it up and pack it with sand if you can it works kind like a lime box. and i would pre heat it to 175 F not 250F. but what do i know im just a boiler maker and certified welder.



The Fat Kid

Andy

 

[KWentling]

175*? I've never heard of a preheat that low. That's not even enough to get rid of the moisture. I've also been certified but not a boiler maker. Thats a whole different world. Mine was structural unlimited thickness. As much preheat as possible without disturbing the the termper or damaging anything would be optimum but we don't know what that is and there is also bearings to consider and 250* is the max. recommended heat for them, thus the 250 I recommended. Sand is probably not possible to use but using fire blanket or something to keep the air off it would be good.

Kim

 

[Forrest Nearing]

just tack the nut to the gear... you're just trying to prevent the nut from backing off, the gear is still on the splined shaft, so there will be minimal twisting force, the force will be toward the rear of the shaft, which will produce some twisting force, but if you "lock" the nut to the gear, this will be reduced...



the torque on the nut, some locktite, and a couple set screws (on the updated nut) and 4-6 tacks between the nut and gear? it oughta hold up for a little while

 

[SRadke]

just tack the nut to the gear...

The gears are cast and hardened, I'd be surprised if you could get a weld to stick to it without exotic rod or enough heat to screw up the gear.



-Scott

 

[Dick R]

Hello , I would like to thank all the that have replyed to my questions on welding the fith gear nut to the shaft , this kind of response can only happen on this web site , the response was fantasic , I didn't get it done this mourning ( shopping for the correct welding rods ect ) besides being to darn hot working in the sun and on a blacktop drive , if this repair will hold up anouther 40 to 50 thousand miles fantasic , I just had to do something different , some of the member have repaired their transmission's only to have them fail in less than 10,000 miles , I would bet these nuts were backing off the day they left the factory , even with these problems I beleive we have one heck of a good truck . Dick R

 

[Demon Dodge]

I welded the nut with my mig machine about 10000 miles ago all of it towing heavy. I just had it fail again but haven't had time to pull the back off the trans to see what failed no noise just no 5th gear.

 

[Dick R]

Thanks for all the advise , I did get it running this mourning , torqued the nut to 300 ft lbs after using the liquid lock tight furnished with nut & locked the set srews in place & center punched the nut into the key way on the shaft , but after seeing how soft the nut is I dicided to spot weld the nut onto the shaft in three different spots making sure the weld overlaped from the nut onto the shaft , I just can not imagine the nut coming off , we will see after a some miles , Dick R

 

[edmeyers]

mine backed off with the blue*****als fully splined shaft and updated 5th gear nut when i took it apart i could see no reason why this nut with set screws would hold any better than the stock nut when you install the nut and put the set screws with the brass plugs and tighten down the screw all it does is make more threads now how is that going to hold the twisting force.



my fix was to tighten the nut then use a drill bit smaller than the threads of the set screw holes and slightly drill the shaft enough to run the set screw tip into the shaft thus preventing it from turning at all. after that run another set of set screws in behind the first set. use red loctite on every thing and call it good. i did this 25-30k ago i have not had a problem.



but when i do mine is going to quad 4x4 i spent alot of time talking to dan and i believe he has a solution but he had not gotten a patent at that time so he would only put it in a trans he rebuilt.

 

[Andy Redmond]

Do not recommend the welding. I have personally witnessed a shaft breaking after the welding process. I do know of the welding shop that performed the repair and suspect this may be part of the problem.



Go to the Quad4x4.com site for some interesting reading.



Dan might not have the ultimate fix, but I've seen the problems with the fully splined mainshafts in his tech article.



Admittly he rebuilt transmission is pricey, wouldn't be worth it, to be rid of a problem.



Food for thought.



Andy

 

[Dick R]

Ed , you know I was considering doing what you did by drilling into the shaft to give the set screws something to bit on to to keep the nut from turning off but I was concerned that I would mess up the threads on the nut for the set screws, how hard was it to drill into the shaft seems to me to be pretty hard , I did end up welding the nut to the shaft ( really a Micky Mouse way to repair things ) hope my weld stays as long as your repair . Dick R