Problem with rear end rebuild

[destinbeachman]

I have rebuilt quite a few differentials over the years, but never a Ford 9". With the case side adjusters and the pinion carrier, it should be the easiest, but I've run into something.
Rear is a '77, with an ARB and 4.88s. A while back I broke my transfer case output, and destroyed the driveshaft. I upgrade the output and replaced the driveshaft with another from TW. Shortly thereafter, I started to notice a vibration from the rear. I replaced u-joints, of course. When the transfer case output broke, the driveshaft was completely ruined, with all the yokes egged, and it even ripped the bolts out of the diff yoke. Thinking I possibly hurt the yoke, I got a new one. Here's what I found-
When removing the yoke, i found the pinion nut to be suspiciously lacking in torque. So, okay, I'm pretty sure I banged the rear hard enough to lose the preload. I decided to go through the whole diff to make sure it was right. Ordered a complete kit from WH. Tore the rear down and cleaned it up.
Here is my problem-I installed the inner pinion bearing and started to assemble it into the barrier so I could set up the solid spacers, but the outer pinion bearing is tight on the pinion. This bearing is not supposed to be am interference fit, is it? If so, the pinion would have to be driven out on the carrier several times while setting preload with shims, and I don't see that in any of the information or videos I can find. These bearings(inner and outer) are supposed to be the same, correct? So I couldn't have put the wrong one on first. Am I missing something here?

 

[Kwal]

https://www.diyford.com/ford-9-inch-differential-guide-third-member-assembly/

 

[destinbeachman]

https://www.diyford.com/ford-9-inch-differential-guide-third-member-assembly/

Yup, I see a pic there that says "press in tail bearing" with a picture of an outer pinion bearing. I cannot find another reference regarding pressing the outer pinion bearing other than that mislabeled pic. The "tail bearing" is behind the pinion head.

 

[Apogee]

There are three bearings on the pinion, two tapered roller bearings pressed onto the pinion shaft and one cylindrical roller bearing pressed into the case. The pinion shaft should slide in and out of the cylindrical roller bearing without any force during assembly. If yours does not, then I would suspect you have some sort of problem with one or the other.

FWIW, I set up my pinion shaft bearings in a press to simulate the preload of the pinion nut without actually having to torque the preload nut to 200-225 ft-lb every time.

 

[destinbeachman]

My question is how much of an interference fit is the outer pinion bearing? I see videos of it just sliding right on when assembling the pinion housing. The above poster posted a link to a page where a pic appears to show it being pressed on.

 

[jrussells]

I believe the outer bearing is the same interference fit as the inner bearing.

I rebuilt my rear end earlier this week and i had bought the solid spacer kit to go in it but i shy'd away from it because i didn't want to keep pressing the bearing on and off. Ended up just using the crush sleeve

 

[destinbeachman]

Got it done. Was told by Currie that they could be either way, depending on the gear brand.
So, had to press it on and off a half dozen times.
I'm happy with it now.

 

[.94 OR]

They make setup bearings for this purpose.

Or, if you are rebuilding and will be replacing the bearings, open up the inside of the old bearings so they will slide on and off by hand. Get the preset where you want it, then press the new bearings on once.

 

[Apogee]

My pinion bearings were a relatively light press...not even sure the tonnage gauge registered on the hydraulic press. That said, I set it up initially with the old bearings, and then swapped over to the new bearings for final fitment and checking. I had to take them off 1-2 times IIRC with the press and bearing splitter.