Mojave Center Diff casing...

[Tex Koder]

Okay.. I'm embarrassed to even show it..

Gotten it pre-owned and had thought it was smudges of grease or some such since it was tucked up in the shadows of the center diff mount cover..

I need to open my eyes and inspect more closely!



So my question here is-
Do I replace with the same plastic casing or is it worth getting the aluminum unit?

Thanks in advance for your help and input.

 

[Sandracer_NL]

Making your own 27mm diffs instead of the EXB 29mm ones?
Stock does the job and is cheaper, aluminium is cooler though.Tough call.

 

[djrahbee]

Still kinda new...but I have re-built well over 20 diffs already..lol. I like the metal ones..so far..because the threads in the plastic ones wear out faster the more you service them. Plus they look cooler. I just had a gravel get stuck under one of my plastic ones and put a groove in it. Don't think that would happen if it were metal..right?

 

[slick2500]

The aluminum ones are totally worth it, they do get scratched from rocks but it takes a lot to wear through them.

 

[Tex Koder]

Great.

And just so I'm clear..
I can use any of the 6S Center diffs.. They're all the same..? Among the off-road Bashers that is , correct??

 

[slick2500]

Great.

And just so I'm clear..
I can use any of the 6S Center diffs.. They're all the same..? Among the off-road Bashers that is , correct??

Yes, even the on road cars use the same diff but a different sized spur on the Limitless. I think the Infraction and Felony still use a 50T spur but I cannot remember.

-edit- The only other difference is standard or EXB.

 

[Schlepprock250]

Great.

And just so I'm clear..
I can use any of the 6S Center diffs.. They're all the same..? Among the off-road Bashers that is , correct??

I'm not sure about the Mojave, but go to Horizon Hobby website and download the manual for your rig. It has all part numbers listed in an exploded view of the entire car. Even has exploded views of all your diffs. Very much worth doing.
By the way, I wasn't trying avoid answering your question, but having an exploded view manual with all part numbers listed is a great tool in the arsenal.

 

[Tex Koder]

I'm not sure about the Mojave, but go to Horizon Hobby website and download the manual for your rig. It has all part numbers listed in an exploded view of the entire car. Even has exploded views of all your diffs. Very much worth doing.
By the way, I wasn't trying avoid answering your question, but having an exploded view manual with all part numbers listed is a great tool in the arsenal.

Absolutely.
Thank you.
Yes, I've checked the exploded views online..

I wanted to confirm with other more experienced members who may know from direct usage -if those CDs (from different models) should/can be swapped or IF there's any detrimental effects from doing so ,that a Parts Manual may not indicate...

& Considering I've only been an Arrma owner for a little over 12 months.. I'm trying to absorb as much knowledge as humanly possible.

 

[SrC]

This is normal wear and tear. Usually running in rocky terrain. Gravel. They get stuck at the center diff and the carrier case gets all chewed up. Buy The Arrma metal alloy diff option part. Stay out of the gravel if you can, or check it over as you bash. Metal is best for the center diff. I do this doing a rebuild. Center diff runs hot. I've had one center diff melt completely into a molten lump of metal gears, Oil turned to a black tar with melted plastic. My temp gun showed it was over 200F when this happened. Metal diff at the center is a good upgrade.

 

[Schlepprock250]

Absolutely.
Thank you.
Yes, I've checked the exploded views online..

I wanted to confirm with other more experienced members who may know from direct usage -if those CDs (from different models) should/can be swapped or IF there's any detrimental effects from doing so ,that a Parts Manual may not indicate...

& Considering I've only been an Arrma owner for a little over 12 months.. I'm trying to absorb as much knowledge as humanly possible.

Good plan, that's the only way to go. My OCD forces me to research till I know all there is to know about the current project lol.

 

[RCbuzz]

If it is not leaking and still functions fine, just run it?

 

[SrC]

+1.
Let it blow up. If it runs fine as is. Enjoy driving it until. May last a while more than you think.
Then tear it down and rebuild it. May need a whole new Diff.
JennysRC is a great alternative for these.
Remember to always open the diff, even when New, from the factory. Oil is usually low. Do this every time.

 

[Tex Koder]

If it is not leaking and still functions fine, just run it?

I can see small portions of the screws showing through the casing.. But No leaks. And it 'feels' okay.

I will decide on and order a backup now, just to have it immediately on hand..

I'll definitely Abuse it til it gives up and melts.

+1.

Let it blow up. If it runs fine as is. Enjoy driving it until. May last a while more than you think.
Then tear it down and rebuild it. May need a whole new Diff.

JennysRC is a great alternative for these.

I've got my Jenny's cart loaded..

 

[SrC]

Great idea to install the 4 screws into the cups holes to keep oil out while filling and bleeding it.

 

[slick2500]

Great idea to install the 4 screws into the cups holes to keep oil out while filling and bleeding it.

View attachment 263640

Do those vacuum things work pretty good I'm assuming?

 

[SrC]

The Pro Track guys use Vacuum pumps for their shocks and diffs. I use the Large Tamiya one. It will fit tall 1/8 shocks and diffs. A few brands also make electric ones. Not needed.
For bashing, some might say overkill. But if you are all into your diffs, this is what you want. Great for shock filling also. And Arrma 6s diffs tend to need much attention to detail and rebuilt often enough.
In the pix you can see that under a vacuum, the diff oil has so much air in it. Under a vacuum it boils out the air. Does it way faster. Let it sit there until you don't see anymore air bubbles. Removing all the air, makes for more volume of oil to be added. The thicker the oil, the more time it needs to bleed out the air. I would have to let the diff sit uncovered for an hour or more, sometimes overnight with 500k and thicker oil, for the air to escape. The factory obviously doesn't go the extra mile doing this, and I feel that is why most diffs out the box are consistently underfilled. The proper level of oil in the diff's carrier cup should be just above and covering the satellite gears' cross pins.
An Underfilled diff that has say 500k in it, will operate like it has 200k/300k in it. Food for thought.
I always open up the Grub screw (with plastic diff cups). Then reinstall it. A drop or so of oil and pressure escapes Releasing any excess pressure and oil that remains in the diff. This way the diff won't blow out oil at the output shaft O-rings or even at the gasket. A common issue. Just another tip. Metal alloy diff cups don't have a grub screw however. I find that filling the diffs is the most time consuming part when done correctly. And it should be. Can't rush the filling procedure.
Been using a vacuum pump for years. Mainly for my 1/10 shock building. With 1/8 rigs having diffs I always do them this way.