TD2 ball diff vs gear diff general use help?

[nicksincrc 122]

Hi, I’m going to be building a TD2 just for general use with something similar to a sports tuned for the moment. Not getting a slipper clutch, I’m wondering if I’m better with a gear differential rather than the ball differential ( never had one) ? I’d need the ball differential nut kit but I could just put the money on a gear differential that will need little to no maintenance? Any thoughts?

[Twinfan 2479]

I have a ball diff Hop-Up in my DT-03 and it's been no issue for general bashing. Personally, I'd use the kit one with the addition of the aluminium nut Hop-Up in your TD2.

I'm planning on using the stock ball diffs in my upcoming TD2 and TD4 builds 

[skom25 2676]

@Twinfan is it possible to adjust DT-03 ball diff without gearbox disassembly? How often do you rebuild it?

[skom25 2676]

20 minutes ago, nicksincrc said:

Hi, I’m going to be building a TD2 just for general use with something similar to a sports tuned for the moment. Not getting a slipper clutch, I’m wondering if I’m better with a gear differential rather than the ball differential ( never had one) ? I’d need the ball differential nut kit but I could just put the money on a gear differential that will need little to no maintenance? Any thoughts?

If you decide to use gear diff, but proper grease to seal it. Without grease, it was total mess in my XV-01, which uses I believe most of the parts as TD2.

[Howards 911]

25 minutes ago, nicksincrc said:

Hi, I’m going to be building a TD2 just for general use with something similar to a sports tuned for the moment. Not getting a slipper clutch, I’m wondering if I’m better with a gear differential rather than the ball differential ( never had one) ? I’d need the ball differential nut kit but I could just put the money on a gear differential that will need little to no maintenance? Any thoughts?

Spend the money on the alloy diff nut and a set of tungsten carbide diff balls. If you build the ball diff right, and set it tight enough it will last just as long as the sealed gear diff before you have to pull it apart and rebuild it. 

The gear diff is only really suitable if you are running on high grip carpet or astro with a particularly powerful brushless motor. It shouldn't be built dry, and any oil you put in it will degrade and loosen up over time making it feel inconsistent.It needs a rebuild on a similar frequency to the ball diff in my experience. 

[Howards 911]

13 minutes ago, skom25 said:

If you decide to use gear diff, but proper grease to seal it. Without grease, it was total mess in my XV-01, which uses I believe most of the parts as TD2.

You need about 20-50k oil in the TD2 gear diff. Built as standard, it does not leak. Any looser and it diffs out too easily and hooks on tight corners. The XV01 ships with 1000 weight oil so I'll let you do the maths as to how much more viscous the oil in the TD2 needs to be! 

[ThunderDragonCy 9114]

Another vote for keeping ball diffs with upgraded diff nuts in the TD2. I have ball diffs in my TD4 and it's lovely. Plus, if you aren't running much power and no slipper, the ball diff does keep a bit of 'give' in the drivetrain because it can slip under high loads. Plus, on lower grip surfaces the ball diff is better for traction. Build it carefully and it will be great.

[nicksincrc 122]

I have an xv01 and have 30k front and 10k rear so I’m familiar with that type of diff and I green slimed the necessary areas. Just never had a ball differential 

[nicksincrc 122]

24 minutes ago, Howards said:

Spend the money on the alloy diff nut and a set of tungsten carbide diff balls. If you build the ball diff right, and set it tight enough it will last just as long as the sealed gear diff before you have to pull it apart and rebuild it. 

The gear diff is only really suitable if you are running on high grip carpet or astro with a particularly powerful brushless motor. It shouldn't be built dry, and any oil you put in it will degrade and loosen up over time making it feel inconsistent.It needs a rebuild on a similar frequency to the ball diff in my experience. 

Are those the Schumacher ones? I’m uk based 

[Twinfan 2479]

31 minutes ago, skom25 said:

@Twinfan is it possible to adjust DT-03 ball diff without gearbox disassembly? How often do you rebuild it?

Yes, you tighten it by removing a driveshaft.

I've never rebuilt it, but the car isn't used regularly as I have other runners too.

[Howards 911]

14 minutes ago, nicksincrc said:

Are those the Schumacher ones

There are lots of suppliers - if the Schumacher ones are the right size then they are a safe bet.

[Otis311 423]

The ball diff included with the TD2 is superb, sans the included plastic nut. Once broken in it is the smoothest diff I have ever had. And yes it is adjustable from the outside of the gearbox.

[Wooders28 5148]

2 hours ago, nicksincrc said:

Are those the Schumacher ones? I’m uk based 

Are they not an odd ball (🙄) size, like 3/32 ? 

Might need to look at Associated etc.

Usually ball diff for loose surface (acts like an LSD) and gear diff for high grip ,as not much slip on the drive axle, can cause the car to understeer (kind of tank steer ,as both wheels are trying to drive forward) under power.

[nicksincrc 122]

Thank you all , I think I’ll give it a go with the upgraded nut and hopefully it gets built correctly 

[Howards 911]

6 minutes ago, Wooders28 said:

Are they not an odd ball (🙄) size, like 3/32 ? 

Yes - they are 3/32. It’s specified in the manual. Plenty of sellers to choose from.

[Smokescreen38 222]

I’ve been running my Td2 with a Speed Passion 5.5T on 2s with the stock drivetrain aside from the aluminum diff nut.  
I have a slipper clutch ready to go but I had finished the car before I got it and I didn’t feel like tearing the car down again just yet when it had been running so well.  It has been driven on pavement only.  No dirt, no grass, no carpet, no jumps. I’ve been pretty easy on it and it had been running gloriously. 

The motor is obviously a lot more powerful than stock.  It pulls hard and clocked in at 40mph on the stock ratio (meaning that it should be pretty close to 60 on 3s).  I built in a lot of expo into the throttle and make a point of not slamming the loud pedal trigger too hard…but now after half a dozen packs, the drivetrain is starting to sound crunchy.  I have yet to dissect the ball diff (because I really don’t want to…) but none of the other gears look damaged.  
 

Is the ball diff that fragile? Did I somehow screw up the assembly?  What is the typical failure mode for a ball diff? 
 

Anyway, I’m considering a gear diff for this thing so any advice would be appreciated. 

 

 

[ThunderDragonCy 9114]

I am no expert on super high power systems, but I think regardless of how careful you are that is a tonne of power through one diff with no slipper. I suspect if you rebuild the diff (the diff gear is really cheap) but put that slipper in you would have better longevity. If you pull it apart and you just need the diff fear I would suggest rebuilding with the slipper and see how you go. Back on the road for a few quid. 

Ultimately a gear diff will be tougher, but make you buy the one with the metal bevel gear internals. 

[Wooders28 5148]

4 hours ago, Smokescreen38 said:

Is the ball diff that fragile? Did I somehow screw up the assembly?  What is the typical failure mode for a ball diff? 

Can be

Probably not, but they need adjusted correctly.

Tamiya seem to only supply steel balls in their ball diffs, and I believe they roll out like sausages, reduce their diameter slightly, and essentially slacken off, hence the tungsten carbide upgrade.

I try to set my slipper, so that slips before the ball diff does, as torque just pulls the centre around, causing heat and wear, in the DF03 it was relatively common to melt the diff.

This is a vid from the tech guy at schumacher, for building one of their diffs, the basics are still the same.

 

 

[Howards 911]

17 hours ago, Smokescreen38 said:

any advice would be appreciated. 

In my experience the idler gear is the one that gives up in this gearbox. Check the teeth for thinning. There’s a steel version of it and a delrin version too if you want something tougher. 

you can hear a ball diff that’s slipping - it barks on throttle. Beyond just slipping, Failure will be melting plastics. 

Check the screws on both the top cover and the lower cover / forward sus mount for snuggedness - if either aren’t down properly it will eat the gears up.