TT-02s grinding while accelerating

[Jonny1053 1]

Hi all! 
Having just built a TT-02s chassis to rally spec for a beautiful Lancia Delta, I have stumbled upon a problem!! Under acceleration there is a harsh grinding noise coming from the rear of the car! While reversing the car is quiet and smooth, but forward under all power range the grinding is very noticeable! 
 

Any advice would be most welcome, I have read some historic threads and checked all that’s been suggested but I can seem to solve the issue! Would like my first Tamiya for 25 years to be special so would really appreciate any help! 
 

Many thanks Jonny1053 

[TurnipJF 9192]

Interesting. I've just built a TT-02 Type S too, and it doesn't make any untoward noises. What have you checked so far? And what upgrades (if any) have you fitted?

[NobbySideways 113]

Have you fitted all the bearings in the prop shafts? (I think there are two at each end). If you spin it by hand does it do it then? Faults inside the diff will only be apparent if the diff is actually operating; i.e. the two wheels on that axle are operating at different speeds.

 

[Jonny1053 1]

Having read some old post, I checked the pinion and rear diff and bevel gears plus tightened the mount screws! The only upgrade I used was a ali prop shaft and prop mounts, everything else is TT-02S! It’s a very harsh grinding noise under acceleration tho ;( 

[Jonny1053 1]

All bearings seem correct and in place to me too! 

[TurnipJF 9192]

On 1/8/2020 at 9:13 PM, Jonny1053 said:

All bearings seem correct and in place to me too! 

Any luck getting to the root of the issue? If not, any chance of uploading a video of it happening, ideally with closeups of the propshaft and outdrives in motion? 

[Jonny1053 1]

TurnipJF, appreciate your help, thanks a lot! I found the problem yes, and wasn’t anything to do with diffs or gearing! Embarrassingly, the problem  was from Subaru rally wheels rubbing on the wheel mounts!! 🤦🏻‍♂️ The plastic is quite tight inside the wheel of the gold blovcks .... much more freedom on the standard road wheels, and hopefully delta rally blocks will be the same! The car sounds great now....looking forward to running it properly! ✌🏽 Might add another car soon....any recommendations? 

[TurnipJF 9192]

Glad you got it sorted. What class of car are you considering next? Another touring car, or something different?

[Jonny1053 1]

I think something different .... 4WD buggy maybe .... but I’m a big fan of the rally cars too!!