Dana 20 front output shaft issue

harrywt

harrywt

Member
My son and I are rebuilding a Dana 20 for his Scout. We've gotten the front shaft shims set up properly but when we put on the yoke and torque it up the shaft binds up, I can't see that we've left out any shims/spacers by looking at the diagrams in our service manual or the diagram that came with the rebuild kit.

Anyone have any ideas?

Thanks,
harry and kristian
 
Are you using a dial indicator to set your end play according to the specs? The only thing I can think of is that you don't have sufficient end play, hence the bind.
 
Yes, we've carefullly adjusted the endplay, that's why this is a mystery. Tightening the rear axle yoke had no effect, only when we tightened the front axle yoke
 
Forgot a symptom. I had this idea that tightening the yoke changed the entire shaft geometry somehow so we loosened the shim retainer plate on the other end of the shaft. We got the bearing on the end of the shaft all loose and sloppy. The shaft was still bound up, so tightening the yoke only cinched up the bearing at the output end of the shaft. This is why I'm thinking we left out some piece that keeps the yoke from pinching this bearing
 
Maybe the front shaft's rear bearing cone isn't on far enough, that is it's not all the way on to the shaft's shoulder for it.

The front output yoke should have no effect on the end play setting. Either something is missing or not positioned correctly on the shaft.

With that in mind, shim packs are not set in stone. Their thickness is adjustable to compensate for variations in bearing tolerances. I remember that the front bearing retainer's gasket thickness was critical too, more like extra thick card stock than heavy paper.
 
I've learned some more. First of all, it'snot the bearing binding, it's the two gears binding against each other, I got fooled. So this means that the "stack" from the "drum" end of the shaft to the bearing has to be just right. I will post some pics tomorrow night.
 
I think I got the problem solved. I found a thrust washer hiding in the parts washer that fits the shaft perfectly and has the correct thickness such that the angle gear of the front output shaft lines up perfectly with the angle gear of the idler shaft.

I installed the shaft but have to re shim the endplay and I ran out of gas last night. Once I get the endplay set I can torque up the yoke to see if the problem is solved but I think I got it.

Pic 1 shows one of the washers I thought might be correct, you can see on the lower left the one I used at first, it's the shiny one. I somehow didn't see that this one didn't fit the shaft snugly. The keyed washer didn't fit at all

pics 2 & 3 show a snap ring that came with the novak rebuild kit but it doesn't work either. However, I found an old t case in the corner of my garage and it does have this snap ring. The old tcase has the fill plug on the end though, is it a Dana 18?

Pics 4-7 show what I believe is the correct thrust washer, right thickness, snug fit on shaft.

Tonight I will finish the install and report back

1.jpg

2.jpg

3.jpg

4.jpg

5.jpg

6.jpg

7.jpg
 
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Methinks the green and white "part" with the "star" laying on the workbench May have had an effect on the assembly???? Especially if there were several in use?????
 
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