400 w/ a brake cant be used on the street ??

[gnsrule]

I was talking to a local trans guy that builds a few 400's around here. Hes tellin me you cant run a 400 w/ a brake on the street cuz on the way the brake is designd. Hes sayin theres an orfice drilled in the direct drum to bleed oil off that leaks too much oil at less than full line pressure. He says ill smoke the direct drum at part throttle cruise becuze of the leak. Ive never run a 400 w/ a brake to know so all help is apreciated. Also, what the good stuff i should be looking for, a hardend input and 34 roller sprag i know about. after that im lost.
Thanks..

 

[chris718]

i personally disagree with this as all our street and strip transmissions feature a bleed hole and heavy duty return springs in the direct drum. also every 400 brake ive seen (
exept ours)uses the dual feed method of applying the hi clutch which means three times the amount of oil is beingsent to the hi gear drum in third gear so that a .060 hole will never empty out the drum faster than the amount of oil being supplied to the hi clutches to clamp the hi frictions to the forward drum and generate 3rd gear. NOW here are some things that will make it work better .install 2 small block chevy head bolt washers on the pr valve ,and install 2 2004r lo reverse case cup plugs in the direct/reverse clutch feed holes in the case .this will raise line pressure 35 psi and stop leaks between the center support and case to the hi clutch.the downside to a 400 transmission with a buick motor is that carefull attention must be payed to crankshaft endplay and convertor charge circuitry to avoid main thrust bearing damage.

 

[WE4]

CK Quote
i personally disagree with this as all our street and strip transmissions feature a bleed hole and heavy duty return springs in the direct drum. also every 400 brake ive seen (
exept ours)uses the dual feed method of applying the hi clutch which means three times the amount of oil is beingsent to the hi gear drum in third gear so that a .060 hole will never empty out the drum faster than the amount of oil being supplied to the hi clutches to clamp the hi frictions to the forward drum and generate 3rd gear.

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I agree with Chris. Bullshiit. It is just not a good idea to USE the brake time after time on the street. But as far as high clutch failure, crap.
I have never had a failure due to this .
Not even an issue. At 200 psi , a .060 hole is not going to matter. The point of the bleed hole is to help piston remain seated at high rpm in low gear and for clean release of the brake when third exhausts.

 

[Whitettype86]

Thats good to here

Thanks for the input on this Chris and Bruce since I'm going to a Turbo 400 w/transbrake in my regal

 

[gnsrule]

What controls line pressure with the use of a brake ?? He says ALL brake kits do it w/ a solinoid where the modulator used to be. Ok, so theres no modulator, whats controling line pressure now ??
Im sure theres optiopns out there, i just dont know about em
Thanks guys
BTW, I dont plan on usein the brake on the street...at least not much Theres no longevity problem anywhere w/ just driveing w/ a brake but not useing it, is there ?? Save the brake for the track.

 

[gnsrule]

ttt

Im takeing this guys advise w/ a grain of salt cuz i know there a few 400's w/ brakes runnin on the street.
With a brake valve body, what controls line pressure ?? Is it locked at full line pressure not regulated ?? And, can a brake valve body be added after the fact ?? or is there other mods that should be done internaly when initially built ?? Just looking from some answers from ppl who know
Thanks guys

 

[MeanBuicks]

Since the modulator is eliminated, yes, the line pressure is regulated internally at a static setting; usually 180-200 psi. Installation of every TH-400 brake design I've seen requires internal transmission modifications. Here's the TCI Trans-Brake instructions for reference.