Where did they break?

[9SECVSIX]

Where did the stock foreward drums break?

thanks
9sec.

 

[Lee Thompson]

broke 2

1 @ the track when car bogged of the line then caught again--coasted to the end.
Second 1 @ a stop sign (4 miles from home)--just enough throttle for the tires to slighty slip in first--snapped when shifted to second--coasted off the road. Was gone 20 minutes to get my trailer--get back and a county mounty had put a sticker on my car--remove it in 24 hours or it will be towed in.
Having said that---the one in my car now has the undercut welded and is holding up to bottom 10's @140. Probably just a good one. I don't know if there is any set #'s. I assume you are asking about a 2004R.

 

[Not Avg 6]

I guessing anytime when above 500 hp at the crank.

 

[Real-T]

If you are asking about where on the unit they break, then they had a tendency to shear off just under the splines where the input shaft engages with Drum's shaft.

If you look at a stock shaft in the drum, you can see that the bottom of the opening for the input shaft goes below where the splines stop, this put shearing stress on the spline area when torque is applied, and since there isn't enough material there, sometimes the shaft shears cleanly off.

The solution was to make the opening more "shallow" thus putting material underneath the splines to add strength. Of course this means that the input shaft will need to be shortened down to whatever is needed for clearance.

Add to that the billet steel used for the shaft, and then the shaft is welded to the drum, and then the whole unit is hardened, adds significant strength to the unit.

 

[9SECVSIX]

Thanks guys. I was just curious because I have never seen a broken one. I took the 200-4R into the low 10's mid 130's before replacing it with a 400 back in the late 90's, I always used NLU converters but had problems burning bands and clutchs. Am going back street now but this new transmission does have the CK drum and input shaft and some of the new tricks in the manual.

9sec.

 

[my 1st gn]

I guessing anytime when above 500 hp at the crank.

maybe around 500 too the tires not to the crank I would guess my car makes 500 crank hp an I have not had any problems yet

 

[bison]

Ive seen them break in cars with under 500hp. Ive noticed some variences on the stock ones in that some of the shafts are drilled shallower than others. A nice stress point right where the splines end. I never broke one but twisted one badly. Was lucky enough to get it out before failure. It was one of the old heat treated ones Art Carr sold me back in 1998 and lasted i pulled 6 3 mos. later to check it. I have since had a billet one from PTS in one of my cars and a CK in another. They look perfect at teardown. Imo anyone who plans on going faster than 12.0 at full weight should replace that drum with a billet one. Much less aggravation in the end. If its too much of an expense then i would sell the car or leave it at a lower performance level because everything for high hp costs money.

 

[WSLN 6]

Mine broke with 15 psi street tires on a 3rd to 2nd downshift. Sheared it clean off just under the splines. Splines had a nice tropical twist to them as well....lol

 

[Not Avg 6]

maybe around 500 too the tires not to the crank I would guess my car makes 500 crank hp an I have not had any problems yet

You're lucky, it's just a matter of time or could be a certain amount of torque.When you upgrade from that PT51 you'll see. Ask Jimmy, he's done mine and a few buddies.

 

[TURBOPOWERED68]

art carr stator snaped right off

 

[my 1st gn]

You're lucky, it's just a matter of time or could be a certain amount of torque.When you upgrade from that PT51 you'll see. Ask Jimmy, he's done mine and a few buddies.

what kinda times are you runing it looks like I might be making a trip back to jimmy's to get one

thanks for the reply