Moparts

8-3/4 Thrust buttons?

Posted By: rarefish

8-3/4 Thrust buttons? - 05/30/23 01:04 PM

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?
Posted By: 6PakBee

Re: 8-3/4 Thrust buttons? - 05/30/23 02:27 PM

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.
Posted By: Alaskan_TA

Re: 8-3/4 Thrust buttons? - 05/30/23 02:32 PM

Originally Posted by rarefish
what is the install method?


With the center section still in the axle housing or out? work
Posted By: DAYCLONA

Re: 8-3/4 Thrust buttons? - 05/30/23 02:46 PM

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

Attached picture reared.JPG
Posted By: rftroy

Re: 8-3/4 Thrust buttons? - 05/30/23 02:55 PM

Originally Posted by DAYCLONA
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

Attached picture IMG_9191.png
Posted By: JohnRR

Re: 8-3/4 Thrust buttons? - 05/30/23 03:00 PM

Originally Posted by DAYCLONA
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


Open rear uses a thrust block held in place by the spider gear pin, just like the cone type .
Posted By: A727Tflite

Re: 8-3/4 Thrust buttons? - 05/30/23 03:58 PM

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

Re: 8-3/4 Thrust buttons? - 05/30/23 04:38 PM

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 wrench scope
Not easy but better than removing the third member and spilling all the gear oil out to install them work twocents
Posted By: hp383

Re: 8-3/4 Thrust buttons? - 05/30/23 06:23 PM

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.
Posted By: JohnRR

Re: 8-3/4 Thrust buttons? - 05/30/23 06:46 PM

Originally Posted by hp383
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?



Correct
Posted By: rarefish

Re: 8-3/4 Thrust buttons? - 06/01/23 01:10 PM

Originally Posted by Alaskan_TA
Originally Posted by rarefish
what is the install method?


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


Center section is out sitting on the bench.
Posted By: JohnRR

Re: 8-3/4 Thrust buttons? - 06/01/23 04:57 PM

Originally Posted by rarefish
Originally Posted by Alaskan_TA
Originally Posted by rarefish
what is the install method?


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


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.
Posted By: Cab_Burge

Re: 8-3/4 Thrust buttons? - 06/01/23 05:18 PM

Originally Posted by rarefish
Originally Posted by Alaskan_TA
[quote=rarefish] what is the install method?
Center section is out sitting 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 scope wrench up
If you can dimple the pin end so it swells up so it won't fall out that is the best way hammer scope up twocents
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