Weld repair of shaft splines

spotcruiser · 05-22-07, 08:35 PM

Would weld repair of 4-speed output shaft splines be effective?

The output splines of my '76 4-speed are damaged where the transfer input gear rides. About half the width of each spline is damaged.

Has anyone ever attempted weld repair of a shaft like this? If I could build up the damaged areas and re-shape them properly, would the repair strengthen or further weaken the splines in that area?

Thanks,
Todd Bull.

Pin_Head · 05-22-07, 08:53 PM

If you have the talent to machine the splines, it would probably be easier to just machine a new shaft from a 4130 billet.

spotcruiser · 05-22-07, 09:20 PM

Well, I was thinking about filing them by hand. The damaged areas are just about 1" long on each spline. I think it could be done, but I'm wondering if it would help or make the splines weaker.

65swb45 · 05-22-07, 10:16 PM

I used to have a guy that provided that exact service. Had an actual spline grinding machine. Of course it didn't hurt that he had equipment precise enough to make bearing broaches for Timken either!

He's since moved on to other things.

Too bad too, as we tested the welds after grinding, and they still came in at the same Rockwell hardness as the rest of the shaft.

Sooooo, to answer your question, yes it can be done, and if you have the patience, you can prolly pull it off.

Next question. Without a professional spline grinder, how long do you think it would take to weld AND properly grind each spline down by hand, or with a peanut grinder?

x16?

Hmmm

Mace · 05-22-07, 11:43 PM

buy a new tranny for ~ $100

Mark W · 05-23-07, 12:56 AM

Short answer... It's possible with the right equipment and skill and experience. In the real world for anyone but the specialist with the expensive dedicated equipment, it's a non-starter.

Used trannys are cheap.

Mark...

Trollhole · 05-23-07, 07:24 AM

Maybe find a cutter that has the same shape and make a little jig that uses a drill or dremel tool. Might make things a little easier.

spotcruiser · 05-23-07, 08:05 PM

Yep, the consensus is to find another tranny. I'm working on that also, but started to wonder about the possibility of fixing the one I have.

Thanks all for the input.

65swb45 · 05-23-07, 10:27 PM

Another thought. Since I rebuild a fair number of trannies, I had also looked into another option back when I was getting these done.

I asked one of the companies that manufactures conversion tailshafts if I could run welded shafts thru the broaches they use to cut their conversion shafts.

They said ABSOLUTELY NOT!

A third option which I saw bandied around a few times over the years [and I hear has some adherents in the 440F FJ62 crowd] is to weld the center of a PTO gear to the back of the imput gear, transferring some of the load to a fresh part of the shaft. Not the way I do things at all, but something I had heard about nonetheless.

Best

Mark A.

Trollhole · 05-24-07, 07:17 AM

Quote:

Originally Posted by 65swb45

A third option which I saw bandied around a few times over the years [and I hear has some adherents in the 440F FJ62 crowd] is to weld the center of a PTO gear to the back of the imput gear, transferring some of the load to a fresh part of the shaft. Not the way I do things at all, but something I had heard about nonetheless.

Best

Mark A.

Now thats an interesting idea.

spotcruiser · 05-24-07, 06:29 PM

Cool idea Mark. I may give that a try.

Thanks,
Todd.

Quote:

Originally Posted by 65swb45

A third option which I saw bandied around a few times over the years [and I hear has some adherents in the 440F FJ62 crowd] is to weld the center of a PTO gear to the back of the imput gear, transferring some of the load to a fresh part of the shaft. Not the way I do things at all, but something I had heard about nonetheless.

Best

Mark A.

shelfboy1 · 05-25-07, 08:05 AM

there are so many 4speeds and parts for sale why waste your time i scrapped 5 of them because i couldnt give them away maybey i should have parted them all had less than 70,000 on them now i feel bad but where i live shipping kills everything good luck

kiwidog · 05-25-07, 09:43 PM

Hi Spotcruiser,

I have done exactly what you are asking. I have 1980 FJ40 and it had spline wear on the main shaft. I had to pull the trans and transfer case when I wanted to fit a PTO winch and needed to install the gear in the transfer case. I just welded the splines up for the inch or so they were worn. If I remember correctly I used a high strength, low heat rod, that has a high nickel content. Go to your local Praxair store and ask them for help.I them filed them out by hand ( triangle shaped mill file) using the good part of the spline as a guide. The other thing I did was use the gear as a bit of a broach once I had the splines close. I did this probably 18 or so years ago and the transmission and transfer case hasn't been out of the truck since. I use the truck for snow plowing in the winter and a little wheeling in the summer on the back forty. It is not registered for the highway. So far it hasn't spun the gear in the shaft and it doesn't fell like there is alot of backlash in the drive train when changing directions. I think I enquired about a new shaft and it was $300 or so that many years ago. I would say go for it. I also think the PTO gear rather than the spacer is better and would make the whole drive system a little stonger,even if you don't have a PTO winch. The older cruiser's used to come with the gear installed from the factory even without the PTO box installed. I think they changed to the spacer to save a little coin.

Hope this helps.

Thanks jb

spotcruiser · 05-26-07, 06:53 AM

Thanks jb. I plan to do one spline as a test. If it goes OK, I'll probably weld up the rest of them.

Todd Bull.

shelfboy1 · 05-27-07, 07:19 AM

not trying to be negative here but a 76 cruiser is worth a little money and what your doing will work ok .but if you sell the truck and you tell a buyer that you welded that shaft and hand filed it will that scare them away and reduce the value of the truck with the amount of 4 speeds floating around for parts it seems so much easier to get a used shaft . either way you go good luck and file carefully

spotcruiser · 05-27-07, 09:11 AM

Point taken. I'm not worried about re-sale value. I still have the '78 that I bought new and I figure I will still have both trucks when I bite the big one. Perhaps my wife should worry about the re-sale value of the '76?

As you have noted, there are a lot of 4-speeds around. Swapping one out only takes a few hours. Surprisingly to me, now that I started looking for it, output shaft spline damage on 4-speeds is really common. I can only assume that the gear is harder than the shaft. Seems to me that it would have made more sense the other way around, since the gear is easier and cheaper to replace.

I have a 5.7 Vortec and NV4500 to install in the next year or two, so it will be a non-issue after that.

shelfboy1 · 05-28-07, 05:15 PM

its good to see people do things the old way my problem is i never see a cruiser except mine with over 70,000 on it i stored 10 4 speeds since the 80s and couldnt give them away . so i figured there may be more ,i see a lot for sale cheap,but sitting down with the welder and file maybey a dremel tool could make for a nice relaxing afternoon good luck