For the Road Warriors: Why are Burnouts in Drive a Bad Idea?

[ScamperTom]

So I have educated myself on the sprag/overrunning clutch issue with 904s and 727s and I understand that you can do a burnout with the selector in drive/manual first as long as the car upshifts and you ease out the burnout. (Of course, plenty of people just leave it in manual second.) There's a plethora of info about this on FABO.

That is not my question.

I'm not asking about transmission explosions here. I'm just wondering about general wear and tear. Is it ok to do a burnout in drive as opposed to the manual gears? Since it's an automatic rather than a manual, once the wheels lose traction, it doesn't seem like a burnout should harm the trans. (Of course, high revs will wear things down faster...) So why does everyone think people are idiots for attempting a burnout?

 

[Fisher]

Heat, heat, heat, is a transmissions worst enemy. At the track the key is to get the tires spinning as fast as possible. I set the line lock, in low gear stab the gas to 5000 rpm grab 2nd gear, then roll out of the water slowly lifting off the gas.. Same on the street no need to do long nasty show off burnouts, just get heat in the tires and the traction compound to the surface of the tires.

 

[RAT ROD AL]

So I have educated myself on the sprag/overrunning clutch issue with 904s and 727s and I understand that you can do a burnout with the selector in drive/manual first as long as the car upshifts and you ease out the burnout. (Of course, plenty of people just leave it in manual second.) There's a plethora of info about this on FABO.

That is not my question.

I'm not asking about transmission explosions here. I'm just wondering about general wear and tear. Is it ok to do a burnout in drive as opposed to the manual gears? Since it's an automatic rather than a manual, once the wheels lose traction, it doesn't seem like a burnout should harm the trans. (Of course, high revs will wear things down faster...) So why does everyone think people are idiots for attempting a burnout?

Richard Rollins thinks burnouts are cool. Need I say more?

 

[1969383S]

Heat, heat, heat, is a transmissions worst enemy. At the track the key is to get the tires spinning as fast as possible. I set the line lock, in low gear stab the gas to 5000 rpm grab 2nd gear, then roll out of the water slowly lifting off the gas.. Same on the street no need to do long nasty show off burnouts, just get heat in the tires and the traction compound to the surface of the tires.

While I agree mostly (heat) I would only run first till it just starts to spin then grab 2nd and run it up to RPM and onto third and exit. It is best to start in 2!

 

[Mopar Tim]

While I agree mostly (heat) I would only run first till it just starts to spin then grab 2nd and run it up to RPM and onto third and exit. It is best to start in 2!

If your car can spin the tires in second gear.

 

[1969383S]

It will

 

[ScamperTom]

Makes sense to heat up the tires as quickly as possible to avoid overheating the transmission. But is there any problem with just leaving it in drive? I don't see how the danger of overheating is any different in drive...

 

[1969383S]

Agree 2nd or drive. It is really and issue with band apply.

 

[kursplat]

curious. how many here have actually destroyed a trans, that otherwise is properly taken care of, by doing burnouts on street tires

 

[MrJLR]

A friend of mine told me doing burnouts on "street" tires makes it worse. ...they're designed for best traction at normal operating temperature.


Jeff

 

[1969383S]

curious. how many here have actually destroyed a trans, that otherwise is properly taken care of, by doing burnouts on street tires

That’s a loaded question, small tires burn easily with little wear on the trans per say. Big tires and strip use are harder on the drivetrain. 904/727 trans lend to 2nd or high gear burnouts for high abuse in boxes at the track. I always ran street radials and tried to bypass the water. When successful I did 1 quick then 2 hard and left in 3 with Modified transgo equipped unit. If I had to get wet then I went 2,3 and out. So if cruising around having fun 1,2,3. You have to look at band apply and how that causes heat in the tranny. Folks have been smoking tires in these cars long before I got one. One thing I know is if you ever have a rear end or shaft failure you better check and replace the sprag and overrun clutch or you will likely have a bad day on your next trip.

 

[Bulldozer]

I did a 335 foot burnout in a 70 Coronet , 440/727 276 sure grip 275/60/15 Firestone Firehawks on blacktop in an apartment complex in Denver Colorado starting out in drive power braking and it shifted through all the gears roasting the tires so good the fire department showed up thinking the buildings were on fire until I rolled down the street on two flats with cords taking paint off the car. that trans was bone stock and never blinked an eye

 

[doogievlg]

I had the same transmission for about 10 years from the time I was 18 through 28. Needless to say that it saw countless burnouts but when a friend of mine rebuilt it a few weeks ago everything looked brand new. I never let the rpm go about 4000 in 1st before shifting to second though. BTW these burnouts were with street tires and slicks. I beat the snot out of that car and the only mechanical failure was a spun bearing.

 

[abodyjoe]

if i do a burnout with a full automatic i get it out of first asap then use second and third gear for the burnout..

 

[famous bob]

if i do a burnout with a full automatic i get it out of first asap then use second and third gear for the burnout..



^^^^^^^^^^^^^^
this sounds right to me.
I have never raced a fully automatic , fast, hi horsepower mopar, they have been manual shift. Wont a fully auto. that is put in second to start with, automatically start in low anyway ??

 

[kursplat]

That’s a loaded question...

yup, that's why i asked it that way. the OP's question was a little vague to me. if he's talking about a track car with slicks that hooks hard that's way different than a street car looking to get new tires every couple months. need to know what kind of apples we're making the orange juice out of . street car / street tires, do however makes the most smoke. personally i'd rather have the car hook up and git

 

[ScamperTom]

Was that a little donut at the end? ;)

The OP's question was a little vague to me. if he's talking about a track car with slicks that hooks hard that's way different than a street car looking to get new tires every couple months. need to know what kind of apples we're making the orange juice out of . street car / street tires, do however makes the most smoke. personally i'd rather have the car hook up and git

I was asking about a street setup. Seems like since burnouts are a necessary part of racing, the car is probably modified to handle them better. I suppose the bones are still the same tho...

But if a mild burnout won't hurt the trans (and 73AbodEE's did not sound mild!) then why are people so paranoid about them? All I've ever heard was "go ahead blow up the trans," "do it if you want a rebuild," etc.

 

[doogievlg]

Was that a little donut at the end? ;)



I was asking about a street setup. Seems like since burnouts are a necessary part of racing, the car is probably modified to handle them better. I suppose the bones are still the same tho...

But if a mild burnout won't hurt the trans (and 73AbodEE's did not sound mild!) then why are people so paranoid about them? All I've ever heard was "go ahead blow up the trans," "do it if you want a rebuild," etc.

I have never really heard of poeple being paranoid about them. Just dont rev it to the moon in first while spinning the tires.

 

[kursplat]

But if a mild burnout won't hurt the trans...then why are people so paranoid about them? All I've ever heard was "go ahead blow up the trans," "do it if you want a rebuild," etc.

kids now-a-days . you wouldn't believe the way we used to hammer these things in the late 70's and 80's when they were already well used. seriously. everyday. multiple times a day. no one kept track of how many miles since the last oil change let alone a trans service. i don't do that now, but most of these cars are lot tougher than you think

 

[RogerRamRod]

Reverse to First Checkmark burnouts were all over the town I grew up in. I also had friends that were fans of Neutral Drops. I remember a guy with his dads push button one legged slant powered car Maybe an early Valiant-cant remember, loved to floor it and keep pushing R-1-R-1-R-1. Crazy ****

 

[Mattax]

I have never really heard of poeple being paranoid about them. Just dont rev it to the moon in first while spinning the tires.

It's the shock when the tires hook. With a stock torqueflite, being in Drive-Low the over running clutch is most vulnerable because it takes load to lock it.
When the clutch gets damaged enough, it doesn't hold and that's when the front drum can spin up as if in reverse. If the tires are spinning good in Drive, the governor and throttle position should shift the transmission into 2nd or Drive. If the transmission is in manual first, the overrunning clutch is still spinning; so again it seems best to put it into 2nd or Drive before letting the tires hook.

This guy seems to have a pretty good handle on the mechanics of it.

These type of explosions are somewhat rare, but if one ever happens to you, believe me you will remember it. There are a number of factors that contribute to this type of failure and even if you disregard the warnings about low gear burnouts with a stock trans in the drive position or the same low gear burnouts with a non LBA valve body, you will likely get away with it for a long time. You may even have a driveline failure, repair the failure without inspecting the transmission and still get away with it. The key is that in order to have a failure of the roller clutch that creates the condition that overspeeds the drum, the little legs that position the wave springs and rollers have to get bent over enough to let them fall out of place plus you have to have enough of them fall out of place so the roller/sprag ceases to hold any longer. This doesn't happen everytime there is a driveline failure or driveline shock and the explosion does not normally occur until after the driveline has been repaired and the car is back on the track. It may happen the first time back or it may take many more burnouts/launches before it fails.

If you choose to ignore the warnings, that's your choice and no one can change that but there are others that would rather not take that chance and take steps to reduce the possibility of this type of failure.

Torqueflite front drums | Unlawfl's Race & Engine Tech | Moparts Forums ##63798

 

[1969383S]

Last time my car saw the track I had to pull through the water box at a 1/8 mile track I had not visited in 5 years and did 2-3 operation. I got chastised by the starter on the line telling me my 1st gear only burnout was a danger! What an idiot! I proceeded to rip a 7.36 on Pro-Track street tires with cast iron full stock exhaust. They would not allow me to run again. My only guess was they did not want a Mopar to win the street legal only race sponsored by the local bow tie dealer that night! Was asked by many afterwards why only one run, told them to ask the track officials and left. No more of that and a fully restored car that only gets a tire spin in the driveway today.

 

[ScamperTom]

So what I'm gathering is that staying in drive (as opposed to 1 or 2) is fine as long as you avoid a transmission blowup and as long as you don't sit there for ten minutes shredding tires. Sounds like these units are a lot tougher than I'm used to!

 

[abodyjoe]

**** you can stay there for 10 minutes as long as it out of first gear.

 

[Cope]

I just killed my 904 doing burnouts.
Put it in first and stabbed the throttle, smoked the tire until the entire parking lot at the shop was FULL of white smoke...

Pulled the car back in the shop and left. Next day went to drive the car and it would hardly back up, drove out the lot and RRRRRERRRE massive slipping in drive. Trans is DONE...now the trans is coming out today..
It may have just been it's time to go or maybe it was the new motor or God knows what but it's done and the last thing I did was a first gear burn out.

I'll post some pics later when I get it out and apart.