Help...New NV4500 mainshaft too small...???

[thrashingcows]

I've been working on getting the NV4500 rebuilt, and converted to 4wd. I just finished assembling the back side of the new fully splined 4wd mainshaft and went to install the rear bearing expecting it to be "tight" and the bearing fell into place!!

I measured my old 2wd mainshaft where the bearing sat and it measure out to 1.877". The new mainshaft bearing surface measures 1.874" and the ID of the new bearing is 1.875".

Any suggestions on what I can do to fix this issue...or should I try and get a replacement mainshaft from the company I bought it from....I bought it months and months ago so I'm sure there will be no warranty, or exchange.

Anyone else run into this issue before?

[ellis93]

Sounds like a non-issue to me.....
If the bearing would "rock" on the shaft (try twisting) then I would worry.

If your that worried about it and lack the time or whatever,you could find a sharp center punch and divot the shaft where the bearing rides. That would tighten it up. You would need to space your punch marks(divots) evenly.

[thrashingcows]

Thanks for the reply. It drops on and I can spin the center of the bearing on the shaft. But I was looking at things and I think once the 5th gear nut is installed it will lock the center of the bearing in place. The 5th gear nut rides/buts up against the center part of the bearing, and once you apply 250ft/lbs it should lock it in place.

[thrashingcows]

OK I think things might be usable as they are. I was looking, and thinking about things and noticed that the 5th gear rides against the inner shell of the bearing.





Once the nut on the 5th gear is torqued to 250 ft/lbs it should lock that inner shell in place.

Thoughts?

[thrashingcows]

I got a response from the company I bought the upgraded mainshaft from...Here's their reply.

HI Brian,

The aftermarket shaft we sell is different in this area. A tight press fit is not required.

When the main shaft 5th gear nut is tightened it draws the bearing cone into the bearing cone so there is not advantage of a tight press for this bearing surface.

We use this same shaft in our own rebuild department and have sold over 3000 shafts with no issues from this bearing journal.

Thank you for your purchase.

Billy

So I guess it's good to go.

[thrashingcows]

Only issue I see with this is that you can't properly set your main shaft end play unless this bearing is torqued down with the 5th gear nut.

Since there is a thrust washer beneath the bearing that needs to be compressed tight, and the other components on the mainshaft that might shift and move once under the load from the 5th gear nut.