Trans Brake Slow Release

NHRA1926 · 01-13-2016, 12:18 PM

I have a Turbo 400 manual valve body transmission with a Trans Brake. My problem is that when I release the thumb switch that is connected to the trans brake solenoid, there is a .5 to .75 second delay before the car actually moves. The switch is not hooked up to any delay box, it is wired directly to the trans brake solenoid. I tried activating the switch with the engine not running but with the electrical power on, and I can hear the solenoid does release as soon as I let go of the switch. Any ideas as to why this is happening?

FireSale · 01-13-2016, 01:20 PM

Give us more info on your torque converter and trans brake. Which companies made them? Did they come installed in the trans or did you do the conversion? What is the stall speed of the converter and what launch rpm are you using. Lots of stuff going on in there.

Dale

NHRA1926 · 01-13-2016, 02:20 PM

My Local Transmission shop guy did the rebuild and conversion for the trans brake. I remember he had to drill out an area in the valve body for the installation of the brake. I'm Using an Ultimate Converter's 5200 rpm converter. It doesn't matter what rpm the engine is at for the slow release. It's the same at idle as it is under full throttle with the two step at 2,000 rpm or 4,000 rpm. Is there a certain line pressure that the trans should be at when using a trans brake?

FireSale · 01-13-2016, 05:17 PM

I run a TCI Street Fighter C4 with a brake in my Mustang. They have a tech section at their site with a list of line pressures gear by gear for all transmissions they deal with, including the Turbo 400. Here's the link:

http://www.tciauto.com/tc/trans-line-pressure

Looks like 180-200 for a TB in a TH400 no matter what gear.

I've heard of drilling in a trans case to convert to brake and if it wasn't done correctly it could be your problem. My TCI came with a reverse pattern manual valve body with the trans brake built in.

If the line pressures check out take a look at the return spring in the solenoid setup. It's responsible for moving the pin out of the way to return the trans to normal operation. You should hear a very crisp snap when you release the button with the engine off.

Dale

ss3011 · 01-13-2016, 06:02 PM

Did your trans guy drill a bleed hole in the Direct Clutch housing, and add extra release springs to the Direct Clutch Apply Piston ? Both modifications are important for a clean release .

NHRA1926 · 01-14-2016, 12:35 AM

Not sure about the bleed hole in the direct clutch or the extra springs. Not sure if I would understand where the "Pin" is for the brake solenoid but maybe my tranny guy will. I did down load the pressure chart from the TCI sight that you offered and I'm gonna bring that to my tranny guy and see if he set my line pressure near those numbers. I appreciate all the help as I have the tranny out right now to replace the converter that I had built by Lenny at Ultimate Converters, and I'd like to fix it while it's out of the car. Snow is on the ground here in upstate NY but I don't wanna wait till the last minute to get this figured out before spring weather comes around. Thanks for the info guys.

01-13-2016, 12:18 PM	#1
NHRA1926 Member Join Date: Dec 2015 Location: Bowling green, Ky Posts: 230 Likes: 12 Liked 202 Times in 62 Posts	Trans Brake Slow Release I have a Turbo 400 manual valve body transmission with a Trans Brake. My problem is that when I release the thumb switch that is connected to the trans brake solenoid, there is a .5 to .75 second delay before the car actually moves. The switch is not hooked up to any delay box, it is wired directly to the trans brake solenoid. I tried activating the switch with the engine not running but with the electrical power on, and I can hear the solenoid does release as soon as I let go of the switch. Any ideas as to why this is happening?

01-13-2016, 01:20 PM	#2
FireSale VIP Member Join Date: Feb 2014 Location: Lakewood Washington Posts: 1,407 Likes: 29 Liked 237 Times in 126 Posts	Re: Trans Brake Slow Release Give us more info on your torque converter and trans brake. Which companies made them? Did they come installed in the trans or did you do the conversion? What is the stall speed of the converter and what launch rpm are you using. Lots of stuff going on in there. Dale __________________ Dale Shearon 68 Mustang 6394

01-13-2016, 02:20 PM	#3
NHRA1926 Member Join Date: Dec 2015 Location: Bowling green, Ky Posts: 230 Likes: 12 Liked 202 Times in 62 Posts	Re: Trans Brake Slow Release My Local Transmission shop guy did the rebuild and conversion for the trans brake. I remember he had to drill out an area in the valve body for the installation of the brake. I'm Using an Ultimate Converter's 5200 rpm converter. It doesn't matter what rpm the engine is at for the slow release. It's the same at idle as it is under full throttle with the two step at 2,000 rpm or 4,000 rpm. Is there a certain line pressure that the trans should be at when using a trans brake?

01-13-2016, 05:17 PM	#4
FireSale VIP Member Join Date: Feb 2014 Location: Lakewood Washington Posts: 1,407 Likes: 29 Liked 237 Times in 126 Posts	Re: Trans Brake Slow Release I run a TCI Street Fighter C4 with a brake in my Mustang. They have a tech section at their site with a list of line pressures gear by gear for all transmissions they deal with, including the Turbo 400. Here's the link: http://www.tciauto.com/tc/trans-line-pressure Looks like 180-200 for a TB in a TH400 no matter what gear. I've heard of drilling in a trans case to convert to brake and if it wasn't done correctly it could be your problem. My TCI came with a reverse pattern manual valve body with the trans brake built in. If the line pressures check out take a look at the return spring in the solenoid setup. It's responsible for moving the pin out of the way to return the trans to normal operation. You should hear a very crisp snap when you release the button with the engine off. Dale __________________ Dale Shearon 68 Mustang 6394 Last edited by FireSale; 01-13-2016 at 05:20 PM.

01-13-2016, 06:02 PM	#5
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 906 Likes: 70 Liked 237 Times in 112 Posts	Re: Trans Brake Slow Release Did your trans guy drill a bleed hole in the Direct Clutch housing, and add extra release springs to the Direct Clutch Apply Piston ? Both modifications are important for a clean release .

01-14-2016, 12:35 AM	#6
NHRA1926 Member Join Date: Dec 2015 Location: Bowling green, Ky Posts: 230 Likes: 12 Liked 202 Times in 62 Posts	Re: Trans Brake Slow Release Not sure about the bleed hole in the direct clutch or the extra springs. Not sure if I would understand where the "Pin" is for the brake solenoid but maybe my tranny guy will. I did down load the pressure chart from the TCI sight that you offered and I'm gonna bring that to my tranny guy and see if he set my line pressure near those numbers. I appreciate all the help as I have the tranny out right now to replace the converter that I had built by Lenny at Ultimate Converters, and I'd like to fix it while it's out of the car. Snow is on the ground here in upstate NY but I don't wanna wait till the last minute to get this figured out before spring weather comes around. Thanks for the info guys.