damage can result from doing some seemingly harmless things when using a trans brake

[TurboDiverArt]

Hi Guys,

I have a questions to you transmission guys. I finished reading the book “How To Work With and Modify the Turbo Hydra-Matic 400 Transmission” by Ron Sessions. One area I found disturbing. In the section on “High Performance and Heavy Duty Modifications” under “Transmission Brakes”. Talking about internally activated trans brakes (as opposed to external clamp type ones), he says, “All kits come with installation instructions, operating tips and cautions. Read them carefully. In most designs, transmission damage can result from doing some seemingly harmless things such as coasting down in neutral or doing burnouts using the transmission brake.” Uh, Oh, I do this all the time. Since I drive the car to the track and it typically gets a little warm in stop and go traffic, I pop it into neutral when coming up to a light so that I can idle the motor when getting the increased flow while decelerating. Usually when I’m doing this I’ll pop it into neutral at 50 MPH and coast down to a stop. Have I hurt my transmission?

Thanks in advance.

 

[The Radius Kid]

I would say that unless you let that CAMF Rich drive it down to Dunkin's,you should be allright.

 

[chris718]

NEVER COAST DOWN IN NEUTRAL ABOVE 5000 RPMS BECAUSE WHEN YOU DO THIS THE REAR WHEELS ARE DRIVING THE TRANS NOT THE ENGINE . YOU HAVE NOW ALLOWED THE HI DRUM TO FREEWEEL AT AN RPM MUCH HIGHER THAN ITS BURST SPEED .THIS CAN CAUSE AN EXPLOSION THAT CAN KILL YOU.THE DRUM CAN COME OUT OF THE TRANS AND KILL THE DRIVER .OR CAUSE YOU TO LOOSE CONTROL OF THE VEHICLE LIKE PLAYING RUSSIAN ROULEETE .what is the purpose of using the brake 4 a burnout .?never roast the tires in first and upshift unless you like buying hi drums and sprags every week .i know that book but if you like th400s read the build sheets on my site 4 the 400s ckperformance.com click gm then 400

 

[PTS XTREME]

Yes, VERY true.

Overspeeding high drum , especially a stock style cast drum , will kill you. NEVER neutral a TH 400 trans at speed. Then again, you may have a wife you want away from, in which case this could be your way out LOL

Bruce
WE4

 

[chris718]

we build a 400 with a safety neutral that has PAY ATTENTION THIS CAN BE CONFUSING a revised shift pattern . it is park ,reverse and neutral together (reverse w/the tb button on ,),low ,second , high ,and the gear formerly known as hi is "safety neutral"which locks the hi drum to the input shaft eliminating the freeweeling and explosions .special thanks to my good friend steve griner the originator of this technology .

 

[TurboDiverArt]

Originally posted by chris718
NEVER COAST DOWN IN NEUTRAL ABOVE 5000 RPMS BECAUSE WHEN YOU DO THIS THE REAR WHEELS ARE DRIVING THE TRANS NOT THE ENGINE . YOU HAVE NOW ALLOWED THE HI DRUM TO FREEWEEL AT AN RPM MUCH HIGHER THAN ITS BURST SPEED .THIS CAN CAUSE AN EXPLOSION THAT CAN KILL YOU.THE DRUM CAN COME OUT OF THE TRANS AND KILL THE DRIVER .OR CAUSE YOU TO LOOSE CONTROL OF THE VEHICLE LIKE PLAYING RUSSIAN ROULEETE .what is the purpose of using the brake 4 a burnout .?never roast the tires in first and upshift unless you like buying hi drums and sprags every week .i know that book but if you like th400s read the build sheets on my site 4 the 400s ckperformance.com click gm then 400

Chris, I'll check out your web site.
I never pop it into neutral at that high of an RPM. I never do it at the track, only when driving to and from the track and never after I was on it (which is pretty much never on the street). I do it as I'm cruising to the track and then the light changes to red and I need to stop. I'll pop it into neutral and coast up to the light to help cool things down. RPM's are never above 2500. With the 4000 stall converter the RPM's practically drop to idle anyway when letting off the gas at 2500 RPM's. Drop at least below 1200 RPM's.

What do you mean, never do a burnout in first and up shift? With a manual valve body, how are you going to really heat up the slicks without shifting out of first? I start in first off the line lock then shift into second keeping the rpm's below 5000 and the MPH below about 70.
I have no idea what Ron Sessions was talking about doing a burnout with the trans brake, I was just quoting. Maybe he was talking about launching with the brake to instantly brake the tired loose on the street and keeping them roasting to do a smoky burnout? I have no idea.

 

[TurboDiverArt]

Originally posted by The Radius Kid
I would say that unless you let that CAMF Rich drive it down to Dunkin's,you should be allright.

Did that 4 times in Bristol so he could make his 330' and half track passes. Damn SOB does a full track pass on the last run and goes 10.2 @135. Naturally this was after he almost put into the wall 3 times on the first pass. Good thing he's a close friend..... At least he has the seat time in his GN to correct it each time and then the sense to completely get out of it as 3 time’s a charm! His only comment afterwards was, “WOW manual steering doesn’t correct as fast as power steering, I just kept on turning….” J

 

[TurboDiverArt]

Interesting but in reading Ron's book it never mentioned this anywhere else but in the section on Trans Brakes. Led me to think that when you have a trans brake you shouldn't do this.

Good thing NHRA requires an SFI trans shield. Like I keep saying to the people that don't follow the rules, they are there to save your life. The NHRA rule book specifically says the trans shield is to shield against exploding drums. I never knew this could happen when coasting in neutral. Personally, if I'm letting off at above 5000 RPM's I wouldn't want to pop it into neutral and lose all throttle control.

Thanks for the info!

 

[chris718]

start the burnout in 2nd gear and then upshift to high gear.(unless of course we are looking to get the attention of some hot women in the pits)heating the tires like this allows better traction and doesnt put aload thru the sprag when you hit 2nd .a one two shift with the car in motion tends to be absorbed by the chassis and asphault not that 34 element sprag by itself which gets hit when doin the burnout .this teqnique of staging also may have a psychological effect on your opponent making him overconfident and perhaps eating the lite . its great for street racing too.sounds like your doing the rite thing anyway.it helps keep the convertor together also .

 

[TurboDiverArt]

Originally posted by chris718
start the burnout in 2nd gear and then upshift to high gear.(unless of course we are looking to get the attention of some hot women in the pits)heating the tires like this allows better traction and doesnt put aload thru the sprag when you hit 2nd .a one two shift with the car in motion tends to be absorbed by the chassis and asphault not that 34 element sprag by itself which gets hit when doin the burnout .this teqnique of staging also may have a psychological effect on your opponent making him overconfident and perhaps eating the lite . its great for street racing too.sounds like your doing the rite thing anyway.it helps keep the convertor together also .

1-2 shift when heating the slicks puts that much stress on the sprag when in the water box? If I have to shift into third while keeping the RPM's above the 4000 stall speed I'll be spinning the tires at like 100+ MPH. Just never thought this was too safe so never did it.

 

[chris718]

did you find the spec sheets interesting /?we also make different ratio planetary gears .not john kilgores .

 

[Buicksx2]

Originally posted by TurboDiverArt
Did that 4 times in Bristol so he could make his 330' and half track passes. Damn SOB does a full track pass on the last run and goes 10.2 @135. Naturally this was after he almost put into the wall 3 times on the first pass. Good thing he's a close friend..... At least he has the seat time in his GN to correct it each time and then the sense to completely get out of it as 3 time’s a charm! His only comment afterwards was, “WOW manual steering doesn’t correct as fast as power steering, I just kept on turning….” J

>>>> John,

Yeah Artie is 100% right in his above statements. The 10.2@135 was a hoot, my quickest pass in a car to date, thanks Artie, have to add that in my signature.

I figured after the car went right 3 times and the manual steering wasnt reactiong as i had hoped it was a good idea to abandon the 1st run. I told Art either this car is quicker than I expected off the line or I did something wrong. He says yeah you did your burnout mostly in water and still had some water on the tires....hmmm that could do it. The rest of the runs went fine and the last one was great. But ya should really have that steering fix Art......lol.

 

[TurboDiverArt]

Originally posted by chris718
did you find the spec sheets interesting /?we also make different ratio planetary gears .not john kilgores .

Yes, looks like lots of good stuff in them! Thanks for the link, I want to also finish reading the tech articles too.

 

[TurboDiverArt]

Originally posted by Buicksx2
>>>> John,

Yeah Artie is 100% right in his above statements. The 10.2@135 was a hoot, my quickest pass in a car to date, thanks Artie, have to add that in my signature.

I figured after the car went right 3 times and the manual steering wasnt reactiong as i had hoped it was a good idea to abandon the 1st run. I told Art either this car is quicker than I expected off the line or I did something wrong. He says yeah you did your burnout mostly in water and still had some water on the tires....hmmm that could do it. The rest of the runs went fine and the last one was great. But ya should really have that steering fix Art......lol.

Trust me bro, if you had been turning on the power steering chuck with no power steering pump I'd still be scraping retaining wall cement out of my fender....

 

[The Radius Kid]

Originally posted by TurboDiverArt
Did that 4 times in Bristol so he could make his 330' and half track passes. Damn SOB does a full track pass on the last run and goes 10.2 @135. Naturally this was after he almost put into the wall 3 times on the first pass. Good thing he's a close friend..... At least he has the seat time in his GN to correct it each time and then the sense to completely get out of it as 3 time’s a charm! His only comment afterwards was, “WOW manual steering doesn’t correct as fast as power steering, I just kept on turning….” J

Yup,he's something else.
Now this brings me to my next question;A long time ago a stock car racer taught me to always put the car in neutral if you lose it.
This takes the load off of the drivetrain and helps to gain control back.
Works everytime.
Now you tell me that I may wind up wearing schrapnel if I do that at speed?
Oh boy!

 

[TurboDiverArt]

Originally posted by The Radius Kid
Yup,he's something else.
Now this brings me to my next question;A long time ago a stock car racer taught me to always put the car in neutral if you lose it.
This takes the load off of the drivetrain and helps to gain control back.
Works everytime.
Now you tell me that I may wind up wearing schrapnel if I do that at speed?
Oh boy!

I don't know about that. I've always understood that with a spool, letting off can make things hairy, make the car whip around in the other direction. I think this is correct, maybe not.