For those "well my tranny never blew up" fools...

...just a reminder. Listen to the advice you are given.

An oldie but goodie...

A really bad day down under for a Mopar racer on the south end of this planet
i hope he wasn't hurt also

Thats Brett my enhind builder . Foot brake


Tex

He shoulda had a steel jacketed aluminum front drum !

been there done that 727 are well known for that,so buy a 6k trans so it wont happen

Low band apply valve body and a billet drum cures this.

8.75 rear? Place your bets!!

Being down under I would bet 9" 8 3/4 parts probably harder to find over there and we all know how easy they break

Gus

I've seen at least 3 of them let go in person in similar fashion.

I've never seen a glide come apart like a 727.

The sky is falling The sky is falling. Everything will break

Never ever do a burn out starting in first gear. Never! Get a manual valve body.

That's all it takes.

And pull it and check/fix it if you break anything in the driveline under power.

And no low gear burnouts.





Correction. Everything can break. But there are simple, well known steps to take that can prevent it or stop it from being catastrophic.

Did the car twist enough to blow the windshield trim into the air?

I've never exploded a transmission in untold thousands of passes....
You guys worry to much...




Probably not going to happen either.....of course I run MANUAL transmission...

I'm guessing trans parts hit enough of the cowl area that the trim flew off because of it.

I was thinking "was that a coolant line"?

Joe

Yep been there done that. dana 60 broke the rear end. I made it to the 60 ft almost to second gear.

I haven't blown up a 904 during 35 years plus of racing. I have hurt them ,once due to an out of adjustment shifter. I am not required to have a trans shield to run mid 11s but I keep it in just in case. Its a pain when changing a motor or trans but I like having the security of it.

Someone on here once said it's due the stock steel 727 front drum diameter being larger so it can't take the speeds created when the other parts (rear sprag?) fails? 904 rotating parts are small enough that it's less of an issue with those?

Interesting...

So I'm a fool because "my tranny has never blew up"?

Of course there are ways, number one rule is how a burnout is done. I’ve always started in first gear, thousands of times. All the mopar guys I know do it too. Here’s the answer, AFTER the car comes out of the water STOP and put it in first gear, left foot on brake right foot on gas, give some gas to SET the spragg, if it’s broke or weak you’ll feel it. No chirps or dry hops, get in the beams. After the burnout Do not ever go straight to the line, then you’re in a crap shoot. It’s all about understanding why a part breaks. Buying the best parts still won’t keep some from rolling over that spragg, they’re the ones who need it. Every trans expert on here knows when that spragg freewheels (axel-gear break, driveshaft-u-joint) it has a big chance of breaking.

If you use that as justification to not do the simple things to prevent that stock front drum from disintegrating and tearing up the car, yes.

904 roller clutches fail just the same. The stock 904 drum won't disintegrate - the critical speed necessary is just not achievable.

The heavy stock 727 drum will come apart at ~12.5 or 13K or so. With a 2.45 low. that's about 5000 engine RPM and a failed roller clutch.

Have low band apply valvebody, never do burnouts in 1st, etc.

Where did the piece of trim come from? The drivers side (pass. U.S.) gutter?

I think the important lesson here is to use a manual transmission.

At least I wasn't the first one to say in this thread : D

.👍👍👍 Amen

I'll bet there are as many catastrophic engine failures as drum explosions. How many here run a belly pan or a diaper? A rod thru the pan or block at speed can be pretty spooky. Yet it seems many focus on the trans as a bigger safety issue. A good front drum and shield solves the problem. The stock front drum is powdered metal construction. It will spin beyond its design limit if the rear drum is not being held stationary. What holds the rear drum? The roller clutch, and in LBA applications the rear band. When the transmission output shaft is unloaded by excessive tire spin or drivetrain failure it unloads the roller clutch. The roller clutch can fail due to the unloaded condition. Now the front drum can spin to engine rpm x rear gear ratio (2.28). Say the unloaded engine revs to 6000 rpm (or higher). That puts the drum to a minimum of 13,680 rpm. At this speed it can disintegrate. A stock loaded front drum weighs close to 7 lbs. That's a lot of weight slinging around. Personally never had a failure. Seen a few live though. But I've seen even more hit the wall with engine oil or coolant under the tires. In fact I've witnessed more crashes due to chassis failure than the number of trans explosions.
Doug

Great thread....

I always call them "peg leg" tranny's. Always joked lots of old timers who raced 727s walking around with peg legs....

If you break the rear or driveshaft you better pull the trans apart.

Everyone always says "yea but I drove it around and it shifted fine...."

I have related the story before, but the last one I saw, the guy was going to take it to the track. He had fixed a broken rear and was driving around on the street. Called and asked me what I thought. I made him take it out. Half the springs were crushed and the rollers just rattling around loose in there. The other half were holding well enough to drive the car. Would not have survived the first hit. 904. Don't know if it was a LBA VB.

Moving off the spot is not confirmation that the roller clutch is okay.

Even if you do scatter a manual transmission most of the parts just clunk around inside the case and make a hell of a noise

Gus

Unless the clutch disc decides to play chop saw.......

That's why they make scattershields

I saw Bob Lambeck scatter shield after he exploded the clutch pressure plate and flywheel, the can was flatten like M60 tank drove over it, pieces from one of those exploding parts pierce the front passenger side roll bar brace to the front of the right subframe, another piece broke a piece off of the back of the block off. Other parts damaged and pierce the firewall and floor boards. It hurt his driver foot and basically total that 1968 Baracuda that he was racing in B/MP (Modified production) back then in the mid 1970s
He had told me to leave off the block plate off on my 1970 Cuda A/S stocker, he said you didn't really need it I put it back in after that

What was it turning, 9500 rpm?

I agree, Lakewood and others make that block plate for a reason. You bet I installed it in my car too. And a rev limiter!

I doubt that he was shifting any where near 8000, probably nearer to 7600 RPM. Maybe a little higher as he had 396 C.I. destroke pro stock type 426 hemi moor in it back then

This might be the all time greatest, or worst depending on how you look at it, 727 explosion video.

https://www.youtube.com/watch?v=aFc-z5q3inw&list=UUgSq1UVDO4j6YHH5eXBeKNw

I have a 727 in my cuda that has been run for decades and been apart numerous times and freshened, but I want to get a 904 in it here soon.

That looks toasty. Hope he wasn't too scorched.

Is there any video of this one?

Wrong class and wrong track. Never saw a video.

I lived thru one of those out on a country road. I had just got the car all back together and drove it to town and put gas in it. On the way home I turned onto a road and ran it kinda hard and was running along about 45 to 50 mph when the tail housing exploded. It bent the out put shaft which in turn beat the living crap out of the floorboards and bent both seats up. The driveshaft exited out into the ditch never to be found. I count myself very fortunate to escape with no scratches or cuts. Birdtracker

ANUTTER reason to run a 904 trans

Those don’t eXpLoDe like a 727

And when was the last time you owned or worked on a race car?????

famous for that time, neutral launch. Ring er up then push 1. NHRA banned that for a reason.

I imagine that is about the time Clutch-Flites came into the picture and they prone to failures as well. Now with todays clutch technology they might work better

Gus

The scattershield on a 4-speed installation equates to a billet drum in a 727; point being, it's best to prepare for the possibility of a catastrophic failure in either.

You ever see a disc come out whole? It happens, and it's ugly.

Hell, a buddy had a piece of a flywheel come through the driver's side back window of his Fairlane in the traps at Motion. It came out of the 396 Chevelle in the other lane. It blew a hole through a Lakewood scattershield.

What we do can be dangerous. I think the OP's point is use the best parts you can.

Ohhhh boy a good buddy of mine blew one of those up at Norwalk in a front engine dragster that only ran 8.90’s. What a mess and there was a lawsuit because of it. It tore his safety blanket up so bad it looked looked like chopped up fiberglass and a piece hit a guy in the stands.

I love a mope,,,,but if too many show up at a race, be sure it'll be a long day of oil downs lol. LS crowd too

Wasn’t a neutral drop. He never did them. Had no need to.

Luckily it didn’t catch fire, just got his pant leg dirty from the ATF.

I got that poster for my son when he was 15yo or so. He still has it up in his shop after all these years.

And the Easter bunny comes every spring.

Do you know the owner/driver of the 64 personally ?

I do. When I say he never did a neutral drop - I know for a fact.
You are just guessing that he did.

Wasn't the supposed neutral drop that sprayed Buster a '67 car?

Is that even Ron Mancini's signature? The second 9 in 1969 looks suspect. Thought he ran the 1964 in SS/DA class and it was Dallas when the trans blew?

All the info and signature is bogus, and the neutral drop thing gets perpetuated because it sounds “cool”.

tBlooper .... just yesterday I worked ON MY 27 roadster !

And I see you didn’t debate my 904 statement.....

NO NEED to be a GRUMP ... just because its already snowing in WASTELAND!

Florida weather is great .... come on down .....

But PLEASE.... lose the chitty ‘tude ! ... ... and IMAGE ...PElousy mooning Ted !

Pic enclosed ! ...

Very sad when it happens, indeed!

There are many things that can go wrong with a 727.

But a sprag’ failure is probably the worst!

I like a lot of folks have been lucky, I guess?

Home built transmission and 600hp engines, with no serious incidents.

No bulletproof drums and bolt in sprags back in the 20th Century doh...

Burning out through the gears, starting in low and “rolling out” of the bleach...

How did we ever survive???

and to think of all the "J" patches we used to do............ go likehell in reverse, then push the 1 button, or slam the lever into low !
the statement "young and dumb" was aptly applied to us ! i'm sure the Saint of Luck worked overtime to keep us safe !

I don’t frequent those types of establishments.

How can you say that, I personally saw it many times, then there’s the spinning the tires, stagged, before the lights came down? They all tried stuff BEFORE the high stall converters came about. THE reason Sox, Grump, Landy and the rest ran a stick. I imitated that trick with my car back in the 60s felt like the whole car was coming apart. Stopped that real quick. One big time factory racer carried 3 or 4 trans with him to each race. But I guess I’m dreaming, has been a long time. Like the OP said get the best parts in the trans for your peace of mind.

I’m speaking only in regards to the 64 Dodge mentioned here.

Yes, guys were doing the drops back in the day. In fact this driver built 25 transmissions specifically prepared to last longer than a standard 727 would.
Chrysler made them available to factory guys and some others back in the day.

That’s cool, can’t place the guy though. We both older than dirt but you know your stuff, I will listen to ya.

There was an article a LONG time ago about the neutral drop era.
NHRA banned it, so did that directly spur development of the J converter, or was that some years later?

IIRC Chrysler sent an entire trailer of 727s to a race (Indy '67?) because they wanted to go rounds.

What's the deal with neutral starts in the 1960's? Was it ever a common strategy at the drag strip? I have never ever heard anyone proclaim they were a good idea or common. Until now...

Back before converter technology advancements - they were worth some ET.
But the risks were too high.

Thanks

So neutral drops being

"standard operating procedure lets say back in the 70's"

https://www.youtube.com/watch?v=wNJabHbfe2w&ab_channel=UncleTony%27sGarage

is not exactly accurate.

Not SOP ever that I recall. They were used in the eliminators and class when needed. The special units built were good for 15 or 20 runs (depending on the car) then things got sloppy again.

The units we built for Chrysler I think were for the 67 Nats when we were battling some Fords and Chevies for class.

My recollection is that it was at the 67 Nationals that the "No Neutral Starts" signs appeared on the Christmas Tree.

I remember well the "No Neutral Starts" sign. I was there. EVERYONE was doing them, it was before the good converters that are available today. We had a 64 Hemi Dodge there, an aluminum nosed Super Stocker out of Ohio.


I was wondering when I'd see another "if you race a torqueflite you're gonna die" thread. It's been a while.

I'm 70 years old and have been racing one behind a Hemi in a 65 Dodge since 1969, and have never blown one up. In my 53 years of racing, I've seen three let go, and all of them were due to driver error. Build it right, pay attention to what you are doing at all times (which you should be doing anyway), and you won't have an issue.

But, what do I know?

Its not just builder driver error....

If anything breaks in the driveline and you don't pull the trans apart and check the sprag, you are rolling the dice....

Twice now over the years I seen guys who broke rears or driveshafts fix them, drive the car around the pits to make sure the trans was "ok" then proceed to blow the trans up the next pass.

When I was young, I did a lot of stupid stuff with a 727 and never blew one up. However, when my Dart broke the 8 3/4 I did remove and disassemble/inspect the 727, there were no issues.

The number one rule to follow. Even if you have the steel drum it can still ‘roll’ over the sprag, the good drum doesn’t stop that. If anything breaks in the drive train IN FIRST GEAR pull it!

Yep. I was pounded this early, and pounded it into my boys who race wedge cars.

I use low gear for putting it on the trailer, into the garage, and leaving the starting line only. In the water I start in second, and shift to high. With water on the tires it doesn't take much to get them spinning. I NEVER use low in the water, for anything. Why?

I notice a fair number of these explosions are done by cars that also do a little street duty. Go out, blow the tires off in low to impress the local kids, turn the sprag, bolt some meats on it and k-pow, there you go. Then you can blame it on the Transmission itself. Never mind that thousands have been raced for over a half a century, 99 percent of them with no issue.

Keep your stuff in good shape, den on't do stupid stuff, and pay attention. You won't have any problems.

But, what do I know?

I'm under the impression that trans brakes started the 727 explosion before steel or aluminum drums stop that

The transmissions were built way before that. Indy may have been the first and only appearance of that sign.

I've seen a lot of roller clutches fail at the hit footbraking, even for me once. Usually, the guy gets his foot out of it before anything bad happens, or like me, they are using a 904.

If it's not your lucky day, you have a problem. Floor, dash, windshield, roof, feet, legs, etc....

Roller clutches can and will fail. Regardless the good parts used. The bad stuff happens in a 727 with a stock cast drum and the engine spun over 5K if you don't get your foot out of it.