The thrust buttons are missing on a 41 case center section that I have.
I do have a extra set of them, but what is the install method?

This is not intended as a WA comment but if this is what you have:

Thrust Buttons

You put the pin in one of them, put it in the differential, and then while holding it in place drive the other one in.

With the center section still in the axle housing or out?

While on the subject of 8 3/4 rears....I've only used/worked on power lok/Sure grip performance 3rd members....does an "open" 8 3/4 3rd member use thrust buttons as well?

Thanks for any info/help
mikeG

No. The shaft for the spider gears also acts to take the thrust between the two axles.

Correction: It's the shaft for the SIDE gears.

Robert

Open rear uses a thrust block held in place by the spider gear pin, just like the cone type .

Look at the provided schematic again, thrust block is called out verbally - just below the ring gear.

I've used black wheel bearing grease on the end of a cleaned up axle end with the thrust buttons centered on the axle ends and CAREFULLY installed them back in when they fell out removing the axles to replace outer axle grease seals
Not easy but better than removing the third member and spilling all the gear oil out to install them

It's been a long time so please forgive my memory. But if you use the Green bearings the thrust buttons, or block, wasn't needed correct?

I am pretty sure the 8.75 I run has the axles lengthened for full spline engagement with the buttons removed.

Correct

Center section is out sitting on the bench.

A lot easier to put them in without having to do a disassembly with it on the bench.

I would and have used thick black wheel bearing grease around both sides of the buttons and in the pin hole and on the pin to make them stick in the clutch type posi units
If you can dimple the pin end so it swells up so it won't fall out that is the best way