XRAY - Model racing cars

Hi all... Pls help, I do follow the instruction to run in the stock ball diffs. While having fun in the middle of carpark.

The engine seem to be getting higher and higher rev and losing so much on speed. The best word to use is "slipping". I'm wondering why is this so? I checked and my gear matching is still intact. I found out that the front and rear diffs became VERY lose. As i remove the gearbox to check, the ball-diff gear are all still alright.

And then i tighten the front and rear diffs slowly and make the car engine sound slip-less and run normal. Then i checked again to feel the diffs and realise the front and the ball diffs are VERY tight, by turning one of the front/rear wheel, the other wheel will move as the same direction!! Seem almost like a direct shafts!!

Is this normal? Btw my ride is still as new. Although the car is running normal now. What's matter me is that are the diffs suppose to be so TIGHT? A million thanks if all brothers here could give some advise.

I had this happen also but my diffs spun loose and stripped the diff shaft keyed area where the metal plates hold onto the plastic assembly.So they were ruined I also followed the recomended Xray detailed instructions.
It must be the Picco P 0 has too much power so the diffs were the first items not able to withstand the added power allthough the atomic cva driveshaft has held up great.I purchased the atomic diffs and they are installed now.Also the 3 screws that hold the spurgear on all came loose and I had to replace but this time I used med thread lock.Driving in the grass overworked the stock diffs because the engine just sent so much power to the wheels so they slipped to the point of failure on the diffs.

Read the sticky forum on NT/T knowledge thread. It show you how to break-in an adjustment. Running on the grass does overheat thing Cuz, grass has the most resistance then dirt or concrete.

When you turn the left side wheel. the rt side should turn the opposite direction. If it turn the same way it to tight. On the rear it maybe ok, but not advised on the front.

Normally, your diff shouldnt loosen up like that other than the inital break in . If they continue to reloosen this quickly check to see if the locknut nylon threads are stripped. I guess you could add a tiny bit of locktite also to the screw (just make sure it doesnt get on any of the ball/plates). For extra precaution, I also CA/glue my D diff plates to the diff sides so they can't shift.

It never loosened in my case the diff just could not take the extra power and spun the plastic keys that holds the diff metal plates that sandwich the diff balls.Now in my opinion its my fault for hotdoggin my NT18T in the grass and I place no blame on Xray I knew that the option Picco P-0 engine had more power but in the future I will be more careful.As mentioned before I purchased the Atomic diffs and I hope they prove to be more durable
Have fun

Bro phatmonkey,
I'm still wondering if I've stripped the diff shaft keyed area like yours. Do the keyed area you mention is the plastic gear teeth? Do I need to strip open the ball-diff to check for that? Is your stripped ball diff still around? If so, please do take a picture of it and email it to me. A million thank on this so that i can confirm that is my diff are stripped.

Bro geezatec,
both of my front and rear turn the same direction when i turn each of it wheel. Maybe i'll need to lose up the front abit like you mention. As for the rear, i don't think i can losen it, if i do so, the car seem like can't move and carry any high speed. Is this normal?

Bro Mini_Me,
yup, my lock nut rubber is still alright. The diffs nut doesn't lose up itself. The main problem is my front and rear diffs is seem like a direct shaft. No diffs in action at all for now.

Lastly, how to see and check if the diffs are no longer working? When i removed the four screw of the top arms, my gearbox top casing will be removed also, I see a diff in the middle, one big gear on the middle of the diff and one small gear on center. I checked that both gears teeth are alright. Do i have to strip the ball-diffs for further checking? If yes, please do advise no how to check for the problem.

Roger that sir... Guess more or less i know what to tune on my next play... Thank you for sharing... cheers!!