Luke-TBCS

Running a Tamiya EVO 4

Front diff : Ball type
Front suspension : Tamiya soft yellows
Camber : -7 degrees
Toe in : 1

Rear diff : Custom 1.7 countersteer yokomo gears
Rear suspension : Tamiya medium orange
Camber : -5 degrees
Toe in : 3

There is no big shaft play and the whole drive train is very smooth.
The front steering arms have been shaved to allow for more lock, the universal front drive shafts don't seem to be binding on anything that i can see.
The front diff, i have tried my one way and also this ball diff both with the same problem.
When driving it at very low speed the car turns left and right on full lock no problems, its when i give it some proper throttle it unders when steering left.
When testing it manually and pushing it on the ground i put the wheels on full lock then push it and its perfect turning to the right then just unders and continues in a straight line when on full lock left.

It's nothing to do with servo lads it's understeering issues caused by something else, it has full lock on both sides and centered but still no dice.

I have been pushing it across the ground to test it manually and on full lock right it turns fine in that direction when i push it then I push it with full lock left and it just goes straight. This is the same as when i test it driving it. Then I take the back left shock out from the understeering side of the car and it turns fine in both directions when pushed.

So with no rear left shock it's perfect but once back in mega under again.

First thing i could think of would be binding on the left side but i have tried many times to find a bind and no problem, i put it on full lock and throttle on and the front left and right wheels seem to spin the same speed and no delays or binding from either one.

Thx for your guys help really need some!!!