When I took this thing apart, there was no washer under the pinion nut. (I verified because I had videoed me removing the nut, and I went back and watched in slo-mo.)

The nut style/shape was this:


When I bought a new nut from the dealer I received the same style.

From what I remember from all the videos I've watched of disassembly and assembly the nuts were of this type/shape:


And they had a washer.

I've tightened the new nut down to the specified 210 ft-lbs, but haven't yet moved on to the next step of checking the rotating torque using the in-lbs wrench and tightening more if need be.
I haven't moved on because there is still a little bit of front-to-back play when I pull and push on the flange, and I wasn't sure if I needed a washer....???

 

Sorry - forgot to mention:
- old pinion
- reused spacer/crush sleeve shim
- new bearings
- new crush sleeve

 

Well, after checking the rotating torque and seeing that it was very loose and not even close, I went ahead with tightening up without a washer. It took forever trying to go a little at a time, but it turns out at the end that I went too far the last time and overtightened.

So it seems that maybe I don't need a washer - but I do now need to go get another crush sleeve (or two) and try again....

 

If you have to take it apart again, wouldn't hurt to check the dodge deal and see if they have a washer layin' about......

 

So you think I should use a washer with that first style of nut that looks like it has a washer built in?

 

It's called a flange nut, The yellow inside is a thread locker. Both will work the same.

 

Sorry, I'm a little slow....

"Flange nut" I get as the name. Thanks for that.

But when you say, "Both will work the same," do you mean that a flange nut needs a washer just like the other nut type does? Or that the flange nut by itself works the same as the other nut + washer? (Or something else that I'm just not understanding?)

 

I'm kinda thinking the flange nut was OEM and what you got was aftermarket so just needs a washer. If your original flange nut didn't have a washer I'd say that's your answer there.

 

I work with vehicles for living that have tons of flange nuts, and they don't have additional washers under them. Washer is kind of built into the flange nut.

 

To clarify, I purchased an OEM replacement from my local dealer, and it is a flange nut.
The one I removed was a flange nut and had no washer.
I know the "rear-end" was replaced shortly after I got the truck many moons ago; but I didn't know enough then and don't remember the details to recall exactly what that entailed.

This whole extended project is my first time ever doing anything with a differential other than replacing gear oil, so I do not have experience to lean on.

Thanks, y'all!