I have a Neetronics DCCD controller in my car, where I can set a defined DCCD lock percentage to use when braking. I had set this to 20%, as it really improved the braking performance of the car.

All was fine until I had front WHEEL LOCK when braking on snow (ABS disabled), which caused a LOUD high pitched screeeching sound from the gearbox.
I reprogrammed the DCCD controller to run the diff in OPEN mode (0% lock) with brakes applied, and the sound went away. I tried increasing to 10%, then down to 5% - and the problem reappeared.

Does the stock DCCD ECU select 0% lock during braking? Is the DCCD differential mechaniccally designed to LOCK during braking? If you run e.g. 20% lock and LOCK the front wheels, what is actually happening in the differential? Is the screeching sound normal during wheel lock, so it can be ignored?

 

What car do you have?
Is this Neetronics DCCD controller a part of the ecu?

Tony

 

Tony, they are an aftermarket DCCD controller.

 

I have a MY98 Wagon with a JDM 6MT DCCD conversion. To adjust the DCCD, I bought the Neetronics controller - http://www.neetronics.com/neet/senso...troller-2.html

 

Anyone?

 

The stock setup doesn't change the diff lock on braking, only on application of the handbrake. The reason for your noises, are the fronts locking, and the rear not, simple as that, you may find if you go to 100% lock you will get rid of the noise as all 4 wheels will lock (ie the front brakes will assist the rear).

You may want to try experimenting with the oil in your box, you really should try and use an LSD compatible oil, and may find some better smoothness by adding some LSD friction modifier to your oil.

Paul

 

Thanks!

I'll try an LSD oil then, I currently use Mobil 1 75W90 SHC.
I'll run with diff lock on braking and ignore the sounds, as I really enjoyed the improved braking performance.