Lost 5th gear...
 

A couple of weeks ago I was headed home from a nice long (4000+ miles) road trip when all of a sudden I lost 5th gear. I was just cruising along, using cruise control when I started slowing down. I thought I may have hit the cruise button and turned it off. So I pushed the buttons again and nothing happened. I pressed on the gas... still nothing. Downshifted into 4th and that worked. Now.... when I am in mostion, I can't even put it into 5th. If I am stopped I can shift it to where 5th is supposed to be, but nothing happens. I can even take my foot off the clutch while "in 5th" and it doesn't even die. What would be causing this?

sounds to me as if 5th gear backed out totally

https://www.dieselbombers.com/cummin...ar-issues.html

Here is a fix ...still workin good

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

Thank You very much. I will have to look into that. Maybe this weekend I will get it all taken apart. How long did it take for you to fix your buddy's? And is the gear itself always bad? The way I read (understand), is that the nut comes off and the gear slides out. Is that right?

Thats exactly what happens, and thats what happened to yours. You can get a new mainshaft, but you don't need it. Just put it back on there, and weld that puppy good. There are also a few companies that make retainers for them, but welding is my preference. Make sure you do it well, if it breaks the welds and falls off again you'll have to buy a new mainshaft.

doesn't it become unbalanced when you weld it?

If I can do the retainer for now I probably will. I don't know anybody who can weld it for me.

that 97 that I just welded had the retainer nut fail 2 times b4 this.............I am talking the latest and greatest retainer nut with the set scre locks on it

I welded 3 even spots around the nut......tried to keep them to a minium so I wouldnt jeprodise the integrity of the shaft

I dont believe balance is much of an issue

Balance doesn't make a difference, its a short shaft, riding on heavy bearings, and not turning at a remarkable rate. I don't like the retainers either, but with the right mixture of loc-tite, heat, and torque they'll hold on a stock truck. You do need to worry about the welds, don't just go throwing beads on it, the heat can warp the shaft if you do it wrong, and you'll need a strong welder to get good penetration. I've often wondered if a good welder could braze all those parts together, it would hold I'm sure, but the concentration of heat might warp things.

I used a wire feed and high heat but a real quick weld then quenched it with oil

Yes I built a backer plate to keep the splatter from entering the bearings and also I grounded right on the tailshaft to isolate the current away from the bearings

I dont think I put it in the article but one should disconnect the batteries just to protect electrical components