Ran in the Summit points race today at Commerce.After three events I was somewhere in the top 10-12 cars in points. As always my car was consistent. Air was ~2,500' all day. Car ran 10.81 and 10.82 in time trials. I dialed 10.82 for the first round of eliminations and ended up going red with a .497 graemlins/sad.gif The guy I was racing cut a .690 light and ran .25 off his dial. I bought back in the second round only to have my transmission frag second gear. This is the second time this has happened to my tranny. First time it was the intermediate sprag. I feel sure it will be the same thing this time. My car came out of the burnout sort of sideways on the pass the tranny broke. Used the same burnout procedure I've been using. I get the tires wet as I roll through the water. Pull ~5' ahead of the water. Start my burnout in 2nd, run the RPMs to 6k, shift into third, watch for tire smoke, and power our of the burnout in third gear until I just hear the tires bite. I staged as I normally do and footbraked the car to 1,600. As soon as I launch I had really bad wheel spin and immediately shifted the car into second trying to recover from the wheel spin. As soon as I hit second gear the engine bounced off the rev limiter (7k). I lifted off the gas (still in second) and then gave it a little more gas. The car was barely moving in second yet the engine was taching out. I shifted into third and limped on down the track. I could see no fluids were coming out so I came back around to the pits and pulled the car on the trailer. I don't know what it is about me and intermediate sprags????

Oh well, that's racing I suppose. Looks like I'll miss at least one points race while I remove my tranny and get it rebuilt. I may have to go with some stouter aftermarket hard parts to make this 400 live in my car. I really thought these things were tougher. I know my car is heavy and it's ET'ing pretty hard, but still, I only had about 120 passes on it this time. graemlins/angry.gif

Sorry to hear it Ken, but still a bad day racing is still better than a good day at the house smile.gif My neighbor just tore down the th350 that I had in my car for almost 5 years,,,,nothing wrong with it,a little burning on the high gear clutches,but thats it. I think those th350's are tougher than they are given credit for. I just hope ole Jakes th400 will last as long as it did :D

Edit: I start my burnout in 1st,take it to 4500 or so,shift to second, wait for smoke then power to the line,did it the same way with the th350 and never had a problem. :cool:

I'ts not so much power as it is bad odds.
I broke a sprag with only 20 or fewer passes and less than 6k of street miles. Granted it is a full-manual VB, which aint so good for the street. I just thought with my lower power that it would last longer.

O'well, sorry for the bad luck. :(

Hey Ken, looks like it's about time to put that manual tranny back in! ;) :D

Originally posted by 71454Chevelle:
Hey Ken, looks like it's about time to put that manual tranny back in! ;) :D At least with an automatic I've gotten 120 passes between rebuilds smile.gif With the Richmond I was lucky to get 20. Nevermind the fact that I could never dream of a 1.4x 60' time with the stick. Sticks are a lot of fun. Autos have their place too. Rhonda Hartman Smith and John Smith (her husband) were making some shake down runs in her top fuel dragster between rounds at Commerce today. I'm thinking I'll try a direct drive setup like the dragsters next :D

becareful powering out of the water in 2nd gear with a th350.....

BigjimzIII why? I've heard not to power out of the box in high gear so I do it in second.

BigJim...I know my car isnt as fast as Kens,but two full years of pounding on that TH350 with a little high gear clutch burning??? Its tough to argue my burnout procedure.

Having fragged a built 350 last fall, and replacing with a 400 over the winter I am curious as to the "correct" burnout proceedure? What is the best method for trans friendly burnouts with a 400? I have a sinking feeling that the way I was using the 350 may have lead to its early demise? :confused: I am thinking that 2nd gear only burnouts is the way to go with the 400?

People, It is your burnouts that are breaking your transmissions. Go into the water, spin the tires once to get water all the around the tires, then pull forward out of the water and start your burnout, bring your rpm up to 3-4000 shift to second then third to get the tire speed up. When you feel the tires trying to bite get off the gas and let the car come out of the burnout. Coming out of the burnout UNDER POWER is what breaks the transmissions. The same thing will happen on the street if you are burning the tires and they suddenly get traction. Very hard on parts. It makes no difference if it is a 350 or 400 Turbo the sprag will break if subjected to a sudden change in RPM, if under power. I was told this by a tranny builder.

My 350 never broke, I took it out while working fine just to upgrade to a 400...I will not spin my tires in the water,I drive thru the water,,,if you spin your tires in the water as your pulling thru it throws water in the fender wells then it drips back down on your tires while sitting at the line,,,thats not good. 1st to 2nd power to the line and let off,let the tires grab while not under power.

here is some good info from some serious drag racers...give it a read..I changed my burn outs because of it. http://drr.infopop.cc/eve/ubb.x?a=tpc&s=3476075&f=80760912&m=344105081&r=344105081#344105081

Originally posted by Harold Sutton:
People, It is your burnouts that are breaking your transmissions. Go into the water, spin the tires once to get water all the around the tires, then pull forward out of the water and start your burnout, bring your rpm up to 3-4000 shift to second then third to get the tire speed up. When you feel the tires trying to bite get off the gas and let the car come out of the burnout. Coming out of the burnout UNDER POWER is what breaks the transmissions. The same thing will happen on the street if you are burning the tires and they suddenly get traction. Very hard on parts. It makes no difference if it is a 350 or 400 Turbo the sprag will break if subjected to a sudden change in RPM, if under power. I was told this by a tranny builder. Harold,

What you described is EXACTLY how I do my burnouts. As I'm rolling through the water box I whack the gas to get the tires good and wet. Coming out of the burnout I listen for the tires start to bite and let of the gas and coast to the beams. So if not the burnout procedure, what broke my sprag :confused:

Noone likes my burnout procedure,noone likes B&M shift kits,noone likes B&M shifters,or B&M converters and I guess I'm not a serious enough racer,,,,just lucky I guess :rolleyes: . I'd almost be willing to bet that I've been down the track more than anyone else on this board in the last two years, And down the track just as many times as those boys over at DRR. I'm not technically informed like alot of you guys here and there,but I know a little about alot(shade tree) Th350's won't hold up?? yes they will. B&M shift kits,shift too hard?? I think the hard shifting part is what saved the clutches in my old one...no slipping,keep it under load so you are not jolting parts,you won't hurt it,I witnessed the disassembly of it,nothing broken. B&M shifters work great for most street/strip cars,nothing gained in performance there,just make sure you get the linkage set up correctly. I've also run two B&M converters with good luck,my current swap from a B&M 11" conv and th350 to an ATI 10" converter and th400 for the most part has offset itself,nothing gained and if the ATI is a better converter it has offset the additional power that it takes to run a th400. I know,my performance is not that spectacular,avg.60,avg.e.t.,just keep pounding the track,day in day out :D Excuse me for my frustration ;)

Originally posted by Rapid Robert:
Noone likes my burnout procedure,noone likes B&M shift kits,noone likes B&M shifters,or B&M converters and I guess I'm not a serious enough racer,,,,just lucky I guess :rolleyes: . I'd almost be willing to bet that I've been down the track more than anyone else on this board in the last two years, And down the track just as many times as those boys over at DRR. I'm not technically informed like alot of you guys here and there,but I know a little about alot(shade tree) Th350's won't hold up?? yes they will. B&M shift kits,shift too hard?? I think the hard shifting part is what saved the clutches in my old one...no slipping,keep it under load so you are not jolting parts,you won't hurt it,I witnessed the disassembly of it,nothing broken. B&M shifters work great for most street/strip cars,nothing gained in performance there,just make sure you get the linkage set up correctly. I've also run two B&M converters with good luck,my current swap from a B&M 11" conv and th350 to an ATI 10" converter and th400 for the most part has offset itself,nothing gained and if the ATI is a better converter it has offset the additional power that it takes to run a th400. I know,my performance is not that spectacular,avg.60,avg.e.t.,just keep pounding the track,day in day out :D Excuse me for my frustration ;) Bob,

I'm not sure what BigJim meant by his comment about "serious racers" being over at DRR. Regardless of what he or anyone else thinks I am a serious racer. I'm at the track EVERY weekend there is an event to run and I usually manage to go rounds in a very tough field of racers.

Let's not loose sight of the issue here which is BROKEN TRANSMISSIONS. Maybe the burnout prcedure is less critical at your power level? Hell, I don't know. I'm not a transmission builder and I've only got a little over 200 passes on the automatic as I used to race stick cars.

I'd be real interested in hearing from people with real world experience both about what might be going wrong with my tranny, burn out procedure or both.

Jim,

Thanks for the link. I read that DRR thread when it was first posted and that's what caused me to alter my burnout procedure. I used to start my burnout in 2nd and pull out in second without ever changing gears. Oddly enough it didn't break doing it that way. It's only been in this year that I've changed my burnout procedure as described above.

Would spinning thru the water box to clean em off cause the problem? Get the tires all nice and warm,pull up to stage,a little water drips down on the slicks,launch,spin/grab transmission breaks?? The only thing I've broken at the track is rearend mounts(68 Camaro) and the orginal posi unit in my current 12 bolt...and a hood :rolleyes:

I've always done my burnouts completely in third gear, from start to finish on my TH350. I wonder if this is a bad way to go? I just figured that not shifting during the burnout is probably a good thing.

My transmission shifts to 2nd too early and I feel like its straining the transmission and or posi unit, which is about due for clutches or a locker or something.

I surely did not mean any disrespect to anyone...I meant that these guys(some of them) do it for a living..and have programs in the 50K range..I personally know some of these guys at DRR and race with them every weekend for the whole season. When I broke a sprag in my th350, I started investigating...the guys who had living tranny's did the burn out as the link suggested. I was just trying to share what I learned. Rapid Robert..if your having good luck running the B&M stuff...more power to you....If your burnout proceedure is working for you...more power to you..If how ever you step up performance, I might consider looking at some of the heavy hitters who run th350s...and how they do a burn out and the parts they use to keep them living...again no disrespect meant. smile.gif

When you shifted to 2nd, while spinning, it probably hooked again, and the rpm's were probably WAAYYY up...correct?

That sounds like the problem to me.

graemlins/sad.gif graemlins/sad.gif
Sorry to hear about this, Ken!
If I can be of any help, give me a holler for sure. If you can't get a quick turn around on your tranny repair, I've got a fresh TH400 sitting in my garage you're welcome to drop in and abuse. ;)
Must be the weekend for tranny troubles...I smoked the clutch in Anne's Miata. tongue.gif

robert i will agree with you 100 percent never spin the tires going thru the water it will do just as you say going up in the wheel wells to drip back on the tires.if the track sprays the water right all you have to do is drive thru to get tires complely wet.ken maybe you are powering the car out a little to for and the tires are biting real hard befor you let up getting the sprag just my thoughts

Thanks for the thoughts guys.

Brian, that's exactly right.

JYD, what you're saying is possible too, although it didn't break when coming out of the burnout. When I power out of the burnout I do so until the tires just chirp. However, that may be putting too much load on the tranny. Being as it broke shifting into second it's prolly like Brian suggested and the car hooked really hard and it was more than the sprag could stand. I guess I'll know for sure when it comes apart.

Is there anything that can be done to make these things stronger? I see a few companies sell aluminum direct drums that supposedly do away with some parts required with the steel drum and therefore it's stronger. Mine already had a 34 element sprag in it and I believe it was of the hardened variety.

Jakeshoe?

send it to STR in north Jersey.

Steve is the man!

ken if you are using the car just for bracket racing now you may want to look into a glide .they seem to make the consitance alittle better and they are pretty tough one thing is for sure there is alot less parts to break inside

Don't let the tires grab pulling out of the burnout, that is the #1 killer of sprags in any turbo tranny,especially if your still in 2nd gear.Ask me how I know? I have since learned and haven't had any problems other than normal wear in over 10yrs and 5000 passes on a supposedly weaker th350.I use all 3 gears 1st to 2nd at the same time I hit the gas then immediately to 3rd, when I see the smoke let go of the line lock and power out maybe 2 ft at the most and lift.The chirp you here is your sprag screaming in agony ;)

Junkyard,
I disagree, a 3700lb ride is too heavy to consider a glide, as well a TH-400 prepped by the right trans builder, should last as long as any glide.

Its given that nose heavy, full weight, or close to it, chevelles are very tough on parts, especially those in the 10 second range.

Ken,
You did break the sprag in the burnout....
Do you have a full manual VB?

get the tires spinning in 1st after the waterbox, get rpm up but not WOT, shift to 2nd, then to 3rd, then WOT, release brakes, and let off as it begins to hook.

Any local reputable builder can build a decent Th400, there are very few secrets out there anymore. No need to go halfway across the country for a trans.

The aluminum drum is not necessary but DOES take alot of load off the intermediate sprag.

You don't manually downshift from 3rd to 2nd after the run do you?
What VB or kit?
Does it still have an intermediate band?

Pull it out, go to the bookstore get a tech manual on it for some basic assembly info, and get out the wrenches...
We can have ya fixed by next weekend and never leave your garage.
You got a digital cam right?

It could have also popped the intermediate pressure plate snap ring out of the case lugs but it is probably a sprag.
Chris at CKPerformance has a new aluminum drum with a 40 or 42 element sprag...

Email me I'll give you my number and any info you need to get going again.

The broken sprag was probably not caused by the burnout if you came out of the water in third gear. You stated that it spun the tires and you shifted to second to stop the tire spin. When it hooked after the shift to second that placed a tremendous load on the intermediate sprag and caused the failure. I remember that you said your trans was built to Keith Neal. You will be hard pressed to find any better. Just my thoughts and opinions.

As you well know I don't care for the B&M VB kits.
Their hard parts are fine (repackaged), their aluminum pans are nice, their coolers are repackaged but are the best available, their converters are OK. I prefer TCi for an off the shelf type converter but for the typical mild ride a Holeshot converter can work. I would stay away from the Torkmasters though..

However,
Some have had good luck using the B&M stuff. I believe the way it is installed as to how hard it is setup to shift has alot to do with it.
It also seems the TransPak is better than the cheaper kits.
If you install the B&M kit on HD/Towing type setup it is probably fine. Not much recalibration of the accumulators going on.

However the "racing" settings are just too much.

Lots of variables as always,
vehicle weight, rpm, trans type, traction available, build quality, etc, etc..

I even believe a tall sidewall vs. a stiff short one makes a huge difference.

Here's a excerpt of an article I wrote on another site:

The reason they break sprags is the severe loads placed onthe sprag on a 1st to 2nd gear shift.
Remember that the direct drum weighs 14 lbs loaded on a TH400, it is spinning 84% of engine rpm in 1st gear, opposite of engine rotation.
When it shifts to 2nd the sprag must stop the drum from turning.
So on a quick 1-2 shift at 6500 rpm, that little srpag must bring a 14 lb drum from just under 5500 rpm to a complete stop as fast as the shift happens.
Then on a 3rd gear change it goes from the sprag keeping it locked to engine rpm again.
Keep in mind on a manual downshift from 3rd to 2nd it goes from engine rpm to 0 too.
Not a problem on an accelerated downshift like passing gear, but on a decel downshift it is harsh.


Gives an idea of why they break.

Usually they break in the burnout box but the driver doesn't know until he shifts from 1-2.
I have had one break from 1st to 2nd shift but it did shift and it felt like a "double shift" then it started slipping.
I was using a non-preffered VB kit...

Also,
to add to the burnout procedure.

You DO NOT want to be in 2nd when it gets traction under any circumstance.
You NEED to be in 3rd.

Doing a burnout and grabbing traction in 2nd is death to the sprag.

Ken,
You might need to be sure you get a hardened outer race too..

Get it apart and let us know/see exactly what is broke and we can go from there.

Actually n20 is probably right.
Shifting to 2nd while spinning and then getting traction as the car grabbed would also do it.

Sucks either way though..

If your lucky the drum will be OK.

Originally posted by jakeshoe:
Ken,
You did break the sprag in the burnout....
Do you have a full manual VB?

get the tires spinning in 1st after the waterbox, get rpm up but not WOT, shift to 2nd, then to 3rd, then WOT, release brakes, and let off as it begins to hook.

Any local reputable builder can build a decent Th400, there are very few secrets out there anymore. No need to go halfway across the country for a trans.

The aluminum drum is not necessary but DOES take alot of load off the intermediate sprag.

You don't manually downshift from 3rd to 2nd after the run do you?
What VB or kit?
Does it still have an intermediate band?

Pull it out, go to the bookstore get a tech manual on it for some basic assembly info, and get out the wrenches...
We can have ya fixed by next weekend and never leave your garage.
You got a digital cam right?

It could have also popped the intermediate pressure plate snap ring out of the case lugs but it is probably a sprag.
Chris at CKPerformance has a new aluminum drum with a 40 or 42 element sprag...

Email me I'll give you my number and any info you need to get going again. Hi Jake,

I have a full manual valve body. I'm not sure what brand it is. No downshifting at speed. You might recall that's how I broke the tranmission the first time. My tranny has no intermediate band. When it broke the first time I downshifted into second under full power street driving the car. Lesson learned. Since then I never downshift until the car is almostly completely stopped (less than 10-15 mph) as I'm exiting the track. As for the tech manual, I've got one from teh last time. I took it apart myself last time and got it back together. I then took it back to the builder and had them go through it again. He replaced the direct (I think) drum and sprag. The clutches (waffle style) were still all like new so he didn't replace any of those. I think that Brian and a few others are right and the tranny prolly broke when I shifted into second. The reason I think that is that it showed no signs of problems in second gear while doing the burnout. As I mentioned earlier it came out of the burnout (in 3rd) a little weird (real sideways). When I launched I thought someting was wrong with the posi, and when I hit second I was sure I had broke the rear end. It was only after I shifted into third that I realized it was second gear and not the rear. I've already been looking on the CKperformance web site. I've been considering a lower first gear for my tranny for a while. I notice CK makes a 2.66 and 2.75. I'm planning to call them to get a price on the 2.66 first. Would be nice to have a little more starting line multiplication. Right now I have a stock first and 4.11 gears.

2.48 x 4.11 = 10.1928
2.66 x 4.11 = 10.9326 = 7%
2.75 x 4.11 = 11.3025 = 10%

2.75 might be too much. I think a 2.66 would be worth a try (7% increase over current launch gearing).

Jake, thanks for your help. I'll be emailing you and would like to contact you by phone.