How do I remove the input shaft?

[Knightfall]

I picked up a used Mojave and the input cup/shaft is missing from the front. The guy bought a replacement bulkhead off Jenny's, and while I could swap the whole thing, I'd like to learn how to swap just the cup. Never done it before with my other Mojave.

I have already removed the grub screw that was in this "cup". Is there more I need do, or just keep trying to pull it off?

How do I get the plastic off so I can heat the input shaft itself? I assume when its off it should look like this?

 

[#ARRMArcfanboy4life]

I think it only has one screw. Once that is off, use a screwdriver to pry the input cup off.

 

[Knightfall]

I think it only has one screw. Once that is off, use a screwdriver to pry the input cup off.

Felt like I was going to ruin the plastic of the casing and the cover. But it's one of those instances you just don't know how force is needed or not.

 

[SrC]

Quite honestly, the best way is to install the input cup while you have your finger on the inside of the bulkhead. Opening the bulkhead/ diff removed. Finger onto the Input gear, so pressure makes the Input cup seated properly onto the Input gear shaft/Flat, before tightening the set screw. The only way to make sure there will be no Input gear endplay/backlash. Undue wear to the Main gear/Input gear, may result otherwise. Loose/sloppy mesh.
These Safe-D type Input gears/Cups with the plastic jacket suck for most of use. Always wobble. Best to use Plain OE type M2C brand Input cups.
But use what you got there, I imagine.
Don't forget Blue Threadlocker on the grub screw. Let cure for 24 hours before running. It will loosen up otherwise, then it's back to square one again.
This is a high pressure load part.

Edited.

 

[Knightfall]

Quite honestly, the best way is to install the input cup while you have your finger on the inside of the bulkhead. Opening the bulkhead/ diff removed. Finger onto the Input gear, so pressure makes the Input cup seated properly onto the Input gear shaft/Flat, before tightening the set screw. The only way to make sure there will be no Input gear endplay/backlash.
These Safe-D type Input gears with the plastic jacket suck for most of use. Always wobble. Best to use Plain OE type M2C brand Input cups.
But use what you got there, I imagine.

Good advice. For now I just want to use what I have. Putting it on makes sense. It's the removal that has me stumped.

 

[#ARRMArcfanboy4life]

These Safe-D type Input gears/Cups with the plastic jacket suck for most of use. Always wobble.

I wish arrma would fix the wobble. I would put locktite on the grub screw on the old diff cup design and the diff cup would always come off. I tried everything to fix it and nothing worked. I don't like the wobble on the new ones though.

 

[joshludden]

Good advice. For now I just want to use what I have. Putting it on makes sense. It's the removal that has me stumped.

I've had to dremel off that plastic sleeve to get a wobbly input cup off before. Even then it took some prying w/ big screwdriver
& I totally agree w/ @SrC, those stocker input cups suck & it seems like 75% of them wobble. M2c or likewise is the way to go

 

[KnowAir]

I just took my rear input cup off for the first time after nearly 2 years of use. The plastic sleeve had literally been melted into 2 separate pieces from a stuck rock.. had to drill the plastic to find the grub screw,lol. It fought me for sure but I just kept lightly prying with a flat blade screwdriver. Pry rotate a quarter turn, pry, rotate..it'll come off. Is this the new diff from JRC ur pulling the sleeve off of?
That gearbox is pretty strong, I wouldn't be too worried about hurting it.
BTW, kudos to Arrma for the steel bearing sleeve they press into the diff housings, love it. Never seen that before.

 

[SrC]

I wish arrma would fix the wobble. I would put locktite on the grub screw on the old diff cup design and the diff cup would always come off. I tried everything to fix it and nothing worked. I don't like the wobble on the new ones though

.

I have never had any problem with the old design Input cups across all my 6s rigs. Blue TL and I am good.
My Input cups are either M2C or the old style NON Safe-D design. I believe my TLRT is the only rig I have them on. Still no issue falling off, But they do have a slight run out. Is what it is. I left there until.....
The stocker Arrma Cups wear out faster in IMO.
Why I always replace with M2C. Just a given when the time arises.

I just took my rear input cup off for the first time after nearly 2 years of use. The plastic sleeve had literally been melted into 2 separate pieces from a stuck rock.. had to drill the plastic to find the grub screw,lol. It fought me for sure but I just kept lightly prying with a flat blade screwdriver. Pry rotate a quarter turn, pry, rotate..it'll come off. Is this the new diff from JRC ur pulling the sleeve off of?
That gearbox is pretty strong, I wouldn't be too worried about hurting it.
BTW, kudos to Arrma for the steel bearing sleeve they press into the diff housings, love it. Never seen that before.

Very early legacy 6s Arrmas did not use sleeves if I am correct. many revisions/Years ago.
But overheated, bricked input BB's will cause the sleeves to melt into the plastic, the whole bulkhead is toast. Been there a few times. I usually smear light grease on the BB sleeves before inserting the BB's. In case they start to Gall out and get hot.

 

[KnowAir]

I have never had any problem with the old design Input cups across all my 6s rigs. Blue TL and I am good.
My Input cups are either M2C or the old style NON Safe-D design. I believe my TLRT is the only rig I have them on. Still no issue fallung off, But they do have a slight run out. Is what it is. I left there until.....
The stocker Arrma Cups wear out faster in IMO.
Why I always replace with M2C. Just a given when the time arises.

No doubt the M2C is top shelf, but until I need it I just can't justify it. We'll see how the safe d cups work w/o the ridiculous sleeves..what are they keeping safe anyway?

 

[#ARRMArcfanboy4life]

No doubt the M2C is top shelf, but until I need it I just can't justify it. We'll see how the safe d cups work w/o the ridiculous sleeves..what are they keeping safe anyway?

I am pretty sure the thing holding the safe-d cups on is the grub screw being threaded through the plastic. I don't think it will work. The safe-d cups and gears are so that even if the grub screw comes loose, the diff cup won't come off and the diff will still get power.

 

[SrC]

I agree, there is nothing real safe about it that I can see. I am sure it was to address people losing them all the time. Just that it never happened to me.
It was a major compalint. Same with the Safe-D motor Pinions for the Firma Motors they decided to use.
If you are buying your whole diffs/bulkhead Assy from JennysRC anyway, then it is the cheaper way to go.
If you are speed running some serious high speeds, the Safe-D Input cups must go. NG.

 

[#ARRMArcfanboy4life]

Same with the Safe-D motor Pinions for the Firma Motors they decided to use.

With the motor, in the event where something needs to give, with the safe-d gear, the thing breaking will be the pinion and spur teeth.

 

[SrC]

https://m2cracing.net/shop/shop.php#!/M2C-3186-ARRMA-INPUT-SHAFT-CUP-F-R/p/478044610

https://www.arrma-rc.com/en/product/input-shaft-cup-safe-d-exb/ARA310977.html

https://www.arrma-rc.com/en/product/input-shaft-cup-sleeve-4-exb/ARA310976.html

Legacy Input cup below.

https://www.arrma-rc.com/en/product/input-shaft-cup-7x18mm/ARAC5062.html

Pick your poison. As you can see, M2C's are not expensive in reality. OE Wobbly Safe-D input cups are not cheap ($7.00 more) and the sleeves are sold separately. Probably the plastic sleeve thats wobbly mostly.
The Legacy 6s Input cups cost $1.00 more than M2C's. Yet also still available.

With the motor, in the event where something needs to give, with the safe-d gear, the thing breaking will be the pinion and spur teeth.

It is over engineered IMHO. No great advantage. It is more of a Firma Motor "Thing". Marketting. Only Spektrum does this.
Just me.

No doubt the M2C is top shelf, but until I need it I just can't justify it. We'll see how the safe d cups work w/o the ridiculous sleeves..what are they keeping safe anyway?

The Safe-D setup is keyed so in theory won't slip if the grub loosens. The sleeve itself is so it won't slideoff??? IDK what else the sleeves could possibly offer? Again, seems over engineered.

 

[KnowAir]

I am pretty sure the thing holding the safe-d cups on is the grub screw being threaded through the plastic. I don't think it will work. The safe-d cups and gears are so that even if the grub screw comes loose, the diff cup won't come off and the diff will still get power.

Only problem of removing the plastic sleeve is the grub screw is too long. I removed the sleeve from the front diff cup a week ago. 3 or 4 packs throught the mojave with no issues thus far.

 

[Camaroboy383]

Pull the grub screw as you already did .

Remove the rear cover and remove the diff...

Place diff case back down against a surface..

Put a screw driver or hex driver in the end of the cup, in the center, against the shaft..

Hit the driver with a hammer..

It will push the input gear out of the cup...

Viola, done!..

 

[morrjr71]

Pull the grub screw as you already did .

Remove the rear cover and remove the diff...

Place diff case back down against a surface..

Put a screw driver or hex driver in the end of the cup, in the center, against the shaft..

Hit the driver with a hammer..

It will push the input gear out of the cup...

Viola, done!..

That's what I had to do when I replaced the rear diff case with an aluminum diff case from Hot Racing. There was no way the cup was coming off by prying it with a large screwdriver.

 

[SrC]

I usually have to do the above all the time. I like to have a bit more TL on these grubs and allow the shaft and Cup to bind up as well. Some would argue this is not correct, and only Blue TL goes on the Grubs threads. However if you want the Cup to never come off, this is the best way.
And I have never had a cup fall off or loosen while bashing. Use some heat helping to remove it. I feel you should have to tap/muscle them off, knowing they were secure during use. The Grub extending longer than wanting is not tragic. More of an aestetic issue. There won't be any interference resulting being longer than desired. You could always source a shorter one if it matters to you.

 

[KnowAir]

I usually have to do the above all the time. I like to have a bit more TL on these grubs and allow the shaft and Cup to bind up as well. Some would argue this is not correct, and only Blue TL goes on the Grubs threads. However if you want the Cup to never come off, this is the best way.
And I have never had a cup fall off or loosen while bashing. Use some heat helping to remove it. I feel you should have to tap/muscle them off, knowing they were secure during use. The Grub extending longer than wanting is not tragic. More of an aestetic issue. There won't be any interference resulting being longer than desired. You could always source a shorter one if it matters to you.

Aesthetics? Me? Definitely not a priority here. I was more concerned about the grub getting damaged or bound up by a random stone.
I agree, more is better as far as loctite goes in certain locations. I have had my share of input cups loosening over the years..which is why I don't usually clean the dry crusty loctite off the screws, I find it helps keep the screws tight by creating more friction.
Just me.. sometimes I'm just bass ackwards..

 

[SrC]

Feel the same way.
In theory, a removable Retaining Compound would be best suited on the Input shaft.

Notice the price of this below!!!!!!!!!! Who is actually buying this stuff??????? Idiots?

https://www.mscdirect.com/browse/tnpla/96033758?cid=ppc-bing-New - Catchall Campaign - PLA - T_RoAS&mkwid=0HuGcnDv|dc&pcrid=73529890243102&gclid=ebf4daee6a8d19295c5bb9a7e16171f8&gclsrc=3p.ds&?cid=ppc-bing-New - Catchall Campaign - PLA - T_RoAS_0HuGcnDv__be_73529890243102_c_&mkwid=0HuGcnDv|dc&pcrid=73529890243102&product_id=96033758&msclkid=ebf4daee6a8d19295c5bb9a7e16171f8&utm_source=bing&utm_medium=cpc&utm_campaign=New - Catchall Campaign - PLA - T_RoAS&utm_term=4577129467923007&utm_content=Catchall&gclid=ebf4daee6a8d19295c5bb9a7e16171f8&gclsrc=3p.ds