Replace RC10GT ball diff with gear diff?

[cobrakai]

So I've got an RC10GT with a stock ball diff. For some reason I've had bad luck with this diff over the years. It seems to slip under brushless power, and when I tighten it down to the point of not slipping, it gets crunchy fast and breaks the diff thrust screws eventually.

I noticed that some models like the T4 come with a gear diff. Can I swap a gear diff in, or would it not fit? Any ideas to help with this?

Thanks

[shane]

I don’t think so unless maybe the outdrive port holes on the ball diff tranny case can be enlarged to accommodate the out drives of the gear diff (I think I said that right). Not sure if that would work but I believe that the gear diff is not a drop in replacement for the ball diff.

[jwscab]

when associated went to the T4.1, they switched to metric bearings, so the gear diff is a metric setup, you would need metric bearings for the outdrives. It might be close enough to fit with some bearing spacers, or slightly machining the diff case halves. Either way it's kind of tricky.

I would say that you might want to look carefully into a rebuild of your ball diff with the right grease,etc, keep the diff tight and loosen the slipper up a little. The stealth transmission with slipper has been shown to run with pretty wild brushless setups. Based your comments, it sounds like you've done a brushless conversion on the GT. it might be worthwhile to look at some of the later vented or v2 style slippers which can handle higher power for longer.

If that option isn't good enough, and you are handy with modifications, you could retrofit the whole t4.1 transmission in to your chassis. it's a lot of work, but could give you the configuration you are looking for.

[cobrakai]

Thanks for the input. I guess I will start with a proper diff rebuild and see if I can make it work as-is. If it keeps breaking, I will probably swap the entire T4 trans. It looks like it's about the same size as mine.

[jwscab]

what kind of brushless power are you pushing? How many cells? If you are running 3s+ cells and high kV, it's not really designed for it and that will explain why you see frequent failures.

[cobrakai]

Nothing crazy. I've had diff issues even with the stock nitro setup.

I'm only running a 2S 3800kV brushless setup. Similar power to the nitro, more torque.

[mk-Zero]

I routinely run 8.5T brushless motors/2S LiPo in cars with Stealth transmissions, both 2WD and 4WD and don't have any issues, and that's on a very high traction track. You *should* be fine.

[Lonestar]

Some discussion here

https://www.rc10talk.com/viewtopic.php?f=38&t=35460&p=395249&hilit=Rb6#p395249

Stealth lube works, too

[cobrakai]

Alright, I ordered up some new carbide 3/32" diff balls. It looks like ceramic balls are the way to go on the thrust bearing. I am using silicone paste on the diff balls, and EP grease for the thrust bearing. Pretty sure that's the same as the AE grease, and about 2% of the cost.

What are your takes on something like this? https://www.hobbytown.com/2.5x6x3mm-associated-tlr-precision-caged-thrust-bearing-set-ceramic-by-protek-rc-ptk-2026/p469099

I converted to a #4-40 diff screw years ago to remedy the issues I was having. The real issue was probably the crunchy balls though!

[mikea96]

The real issue was probably the crunchy balls though!

No one likes crunchy balls!

[XLR8]

The real issue was probably the crunchy balls though!

No one likes crunchy balls!

[cobrakai]

The real issue was probably the crunchy balls though!

No one likes crunchy balls!

Hey, you never know... LOL

[scr8p]

Did you ever have Schweddy balls?

[RC10th]

I'm not sure silicone paste is going to help you and lead to further frustration. The proper diff lubes aren't super slippery and actually allow the steel balls to bite into the rings. Too slippery of lube and they just slip and slide creating heat which damages everything in the long run.

As an example AE have two different silicone diff lubes, a standard silicone lube for pan cars (red writing), and their stealth lube (black writing) for everything else. If you use the standard/pan car silicone grease in any of the stealth diffs they will slip and destroy themselves.

[Lonestar]

I have no idea what silicon paste is, really...

but AE's small lube tubes are like $3 each and will allow you to rebuild litterally dozens of diff each - and they are the right fluid for the job, in a packaging where it gets properly delivered, too. This is a much better investment than trying to fit a $40 gear diff in a box that wasn't designed for it. Even if they are a cheap industrial compound that AE repackages while x10'ing the price (which is probably the case!)