Chrysler 8 3/4 Axle bearing and Seal R&R...A How To

[threewood]

Hi there from the Netherlands. I stumbled on your (great) topic online. I pulled the axles this week, and a spacer button came along. The other one is lost, probably in the housing. So maybe, using your magnet method, I will not need to pull the diff out to retrieve to spacer button?! That would be amazing. I want to ask you, how did you install these spacer buttons back, with the diff still in the housing? Glued to axles, or a long stick/magnet device?

There was only 1 spacer button. And yes, I glued it to the axle.

Edit: One button for the Eaton TruTrac.

 

[khryslerkid]

Hi there from the Netherlands. I stumbled on your (great) topic online. I pulled the axles this week, and a spacer button came along. The other one is lost, probably in the housing. So maybe, using your magnet method, I will not need to pull the diff out to retrieve to spacer button?! That would be amazing. I want to ask you, how did you install these spacer buttons back, with the diff still in the housing? Glued to axles, or a long stick/magnet device?

This is a set of thrust buttons with the pin that has been taken apart. The red arrows are the buttons, the blue arrow is the pin that holds them together. The buttons are inserted one on each side. If the pin is broken, one of the buttons could be stuck to the axle when removing or fall out into the housing. You need both installed in order to set your axle bearing preload.

 

[Highway6]

There was only 1 spacer button. And yes, I glued it to the axle.

Edit: One button for the Eaton TruTrac.

Ok glued! One button only for the Eaton TruTrac, all clear thanks!

 

[Highway6]

This is a set of thrust buttons with the pin that has been taken apart. The red arrows are the buttons, the blue arrow is the pin that holds them together. The buttons are inserted one on each side. If the pin is broken, one of the buttons could be stuck to the axle when removing or fall out into the housing. You need both installed in order to set your axle bearing preload.
View attachment 1952179

Yes I learned this last week about these buttons and pin constructions, and their purpose. Since only one button came out, and the other one is nowhere to be seen, it might be somewhere in the housing. And the diff will have to be pulled out anyway, before that button will cause damage.
I do wonder if this "lost" button was in place anyway. Because the axle bearing collars on both sides have been rubbing against the axle oil seals. And endplay was too much, before I pulled the axles.

 

[haywire 440]

I’ll add to this informative thread on the thrust button(s) issue. The ‘65 suregrip 3:23 gear ratio had the pinion seal replaced in the 842 case.

I reinstalled the 2 thrust buttons and used a longer split pin, because at first I thought there wasn’t a pin between the buttons. Indeed a short pin was found inside of one of the buttons. I felt it was too short. The longer replacement pin doesn’t exceed the length on the two buttons together.

The buttons and pin are installed now and there is an estimated 1/4” movement when the buttons are slide side to side. I figured this is normal and appropriate movement.

My question “Is this correct?”

3 1/4” pushed in and a flush 3” when pushed in from the other side.

One other addition to this thread is about using cleaning fluids to spray out the old lube and debris. My thoughts were to use carb cleaner or brake cleaner. The FSM states to use Mineral Spirits. After a call to an axle/diff master mechanic he stated that the Carb/Brake cleaners would actually clean the parts of their oily skin and if not coated with axle lube again quickly the steel parts will rust quickly. His advice is to use the Mineral Spirits because it’s petroleum based. I did that and used some brushes to clean it even better. Afterwards it was dumped to drain and air dried. Even then I noticed some rust flash but only on the axle bearing caps. My intention was to refill the case with axle lube which was done. A small paint brush was used on the caps and other parts needing a coat.