TT02B gearbox noises

[jupitertwo]

I'm hoping someone can help identify where I need to make a fix to my TT02B. 🙂

Under normal acceleration I get a nasty cracking noise from the rear gearbox.

• I've reduced the motor to a 17.5t brushless, and I still get the same noises at the same frequency as anything hotter.
• I've run it just fwd and that is quiet.
• I've run it with no rear dog bones, and nice and quiet.
• It's just when fully set up that I get the noise.
• I've gone back down to stock wheels, and no differences. 

The gears and diffs are all stock, not chewed gears etc. Alloy motor mount and prop shaft etc, and a RW pinion. 

Any thoughts, I'm loathe to splash the £30+ on the steel GPM gears if it's not the cure?

[XV Pilot]

The plastic ring gear is well known for its propensity for flexing under power even with a mildly upgraded motor - it is really only suited to the stock Torque Tuned brushed setup.

 

The flexing allows the gears to skip, hence the noise.

 

If the GPM gearset is a bit steep for your pocket, a DF-02 metal diff will also sort the issue quite nicely.

[Zuban]

As XV says it will likely be flexing, I went through the same thing. DF-02 diff and bevel gear is a tough setup, I've abused my tt-02b using df-02 gears with a castle 5700kv motor a lot and no problem. You will need the metal parts bag and the diff housings for the DF-02. I made a video a while back to go over the changes made to mine after being asked a few times, hopefully it can give you some ideas!

 

[jupitertwo]

Thanks guys, great to have an explanation of what's going on.  I hadn't considered that the diff could flex

I'll look at the rear first, and investigate the two options. It's not really the cost, more making sure I didn't buy them and not solve it. 

[Zuban]

the gpm gears weren't available when I built my tt-02b so I went with the df-02 option, good thing about it, is that its cheaper, and that you get lots of other bits in the bag aswell which are very usefull. I am glad to see the gpm steel setup though, so far the df-02 parts have proven reliable but I would expect the gpm parts to be stronger still.

[TwistedxSlayer]

Got a complete GPM diff on order from America for mine, should be here this week hopefully.

[jupitertwo]

12 hours ago, TwistedxSlayer said:

Got a complete GPM diff on order from America for mine, should be here this week hopefully.

Cool. I think I'm going to go the DF02 route, see what that produces

[TwistedxSlayer]

I was gonna go down the DF-02 route but i got giggy on ebay and ordered the GPM one. I may still end up ordering some DF-02 ones so i can run GPM at the rear and DF-02 up front.

[Effigy3]

Just this week I ordered the GPM kit for my daughters TT-02B.  It's coming from China so I should see it maybe mid-July.  Guess there'll be a spate of diff upgrades coming soon to Tamiya Club!

[taffer]

I've recently bought 4 GPM complete kits for 4 diffs to upgrade 2 buggies, all 4 sets seize when assembled

I fixed this by loosening the diff casing screws until the diff ran but was notchy, than ran each diff using a drill until I could gradually screw the diff case properly closed, took about 30mins per diff, still sounds rough but hopefully it will quieten once the 3s is used! 😃

[Effigy3]

1 hour ago, taffer said:

I've recently bought 4 GPM complete kits for 4 diffs to upgrade 2 buggies, all 4 sets seize when assembled

Well this isn't good news...    For $50 per I would expect them to be flawless!

[taffer]

Er yes but I knew it was GPM before purchase so I didn't expect "drop in", although more work than expected! I also used steel cross shafts inside the diff rather than the plastic cross that comes with the kit, makes it slightly looser

Also the 2 joint cups needed filing down to fit smoothly!

So about an hours work to be useable, I did send an email query in but no reply so I proceeded with my "mods"

[taffer]

My tt-02b Ms will be posted soon on TC listing all mods

[TwistedxSlayer]

I really hope that I don't have issues with my GPM diff when it arrives.

[jupitertwo]

7 minutes ago, TwistedxSlayer said:

I really hope that I don't have issues with my GPM diff when it arrives.

Me too. I hadn't expected them to require tailoring to fit

[CJ Topspin]

Does the TT02 differentials work in the TT02B housings?

[TurnipJF]

Yes, they are the same parts, hence the problem. They appear to be designed with touring cars in mind, and are not up to the stresses they face in a buggy with its bigger tyres, likelihood of jumping, etc. 

[TwistedxSlayer]

There are a couple of Tamiya diffs that drop into the TT02B gearbox without any issue. The TT01 and the Tb01 but both will require a change of drive cups and dog bones.