TrendSetter

im ready to start reading plugs on my truck, and ive heard a few things about th400s and 4l80es and i wanted to clarify a few things before i go needlessly destroying things

with th400s i think i heard it was dangerous to shift to neutral at high speed, some drum would overspin and could break?
is there anything i need to know about shutting off the motor and/or shifting into neutral from d3 at 120+ mph?

ive been told you can break a 4l80 by going wot in d4 and you always need to be in d3. the only difference i see in the manualis in d3 that the overrrun band is applied.
can someone explain why this matters?

for clarity sake, vehicle is awd silverado 4l80e with twin turbo 5.3

thanks for any info/advice

brandon6.0

iTrader: (32)

I always race mine in d3 as well. Not good to run it in d4. I usually manual shift anyways so It wouldn't matter. I also usually throw it in neutral at the end of a track run. But that's up to u I don't think it would matter much.

Also on the 4l80e u will need to max out the d1 trans shift points for it to hold first gear until manually shifted to second. Shift kit or not it will shift into second everytime without this done.

TrendSetter

I have the stock column shifter so I just run it in d3 and let the pcm do the work.

So throwing it in neutral and shutting the engine off is ok?

wht/73

I think I've read on the site that it's not recommended.

squarles67

If you shut the motor off you have no fluid flow and no lube, don't do that.

wht/73

I have a compushift controller.
Mine will stay in 1st for as long as I want.
Once I have traction under control, I'll let the controller do the shifting also.