I had a little 'misfortune' down at the track on Saturday. I do my burnout, go to launch... tach it up, dump the clutch and *BANG*... nowheresville. car will rev like normal, no weird noises, but it wont go anywhere. They push me off to the side, I look under the car, and see tranny fluid dripping out.

After getting towed home, i let it sit for a day while i try to get un-pissed off. Tonight i got it on jackstands to take a closer look. Driveshaft broke at the transmission yoke. from a visual glance, it doesnt appear that any damage has been done to the transmission output shaft or tail housing, but i wont know until i can get the rest of the pieces of the drive shaft out, replace the seal, and put some fluid back in it to see if it leaks out from anywhere.

driveshaft was a 3.5" PST "1000+ HP" aluminum driveshaft. dunno how my 350-360rwhp car broke it, but it was used when i got it, so maybe it was already fatigued. They supposedly have a lifetime warranty, so i'm not overly concerned about the driveshaft, i'm more worried about the tranny.

i'm having trouble getting all the pieces of the driveshaft out... one piece i was able to get out with a pen magnet, but the bigger piece wont come out like that, and not enough is sticking out for me to get pliers on. will the transmission seal come out, or does the driveshaft have to come out before the seal will? I tried to take some 'dental picks' and try to get under the driveshaft chunks to pull it out, but coudlnt get under it. i figure if i can get the seal out, i'd have more room to work.

and ya... driveshaft safety loop FTMFW!

 

ouch !!
I would pull the tailshaft housing to get the rest of the pieces and be able to inspect the shaft. that seal definitely needs to be replaced .

 

The seal will pop out with a flathead screwdriver.

Get that out, and that piece should come out, unless the splines got screwed up in that case you may be in for a tranny rebuild, or at least an output shaft.

 

Well, I would def be posting that in the drivetrain sections. Some people love those things because a sponsors sells them primarily.

My 4000+ pound car leaving off the limiter nearly runs on a 3" steel from denny's and I feel safe with that

 

wow no noise?

when my stock driveshaft grenaded it made a hell of a noise, and even made a dent/hole in the floor and that was with a drive shaft loop in the car, thank god i had one cus the damage would have been MUCH worse...and the drive shaft loop was one of the first mods i did to my car years ago and im glad i did

 

After that mess under your car chef I wanna put a 2nd one on the back of mine off the tq arm.

 

Yeah I'm surprised you broke one of those. Goes to show that anything can happen when you race. I hope its as simple as a shaft replacment.

 

yea it was enough to make me want to buy a SFI bellhousing/scattershield with my tax return money when i get around to doing my taxes i will be ordering one and having East Side do the install as usual

 

Probably a really good idea. Freshen that tranny up while it's out too, considering some people can't keep one in a car for a season, yours probably could use it after 97K LOL

 

Luckily no issues yet, that M/C from Tick really made a diff. I got to buy other **** before any track outtings.

 

will it come off while the tranny is still in the car? just remove the shifter and torque arm mount? i really dont want to have to drop the tranny if i dont have to.

from the pictures i posted, the splines *appear* to be fine. I also dont see any cracks in the tailshaft housing, but i wont know for sure till i try to get some fluid in it.

Yes, i also posted in drivetrain forum. and Yes, i purchased it from a sponsor. They directed me to go straight to PST for warranty info. i called, but everyone is at lunch, so they will call me back.

well, it made a loud bang when it broke... by 'no noise', i meant engine noise, like if i mechanically over revved the engine or whatnot.

 

yikes!

 

Well at least it didn't break on the big end of the track.Glad you were able to tow it home.I've broken my share of driveshafts it is a bad feeling when you let go that clutch and you go nowhere.Hope the tranny is alright

 

When you bought the shaft did you measure it out? I've seen alot of driveshafts that are too long which could easilly stress that part of the yoke.

 

no, i didnt measure. I took the vendor's word.

so I popped the seal off and got the rest of the yoke out. here are some pics. they dont match up to the body of the yoke, so obviously pieces got grenaded at the track. You can see in the pictures, that there is another crack going almost all the way around it.

as i had to remove the old seal (which was damaged anyways), i will have to replace the seal/bushing before i can put another shaft in it and put some fluid in there to test for leaks.

 

With how that broke, it was either a manufacturer defect or an installation error.

Torque applied to a tube (like a ds) almost always causes a break that's straight-ish across assuming the metal is uniformly dense (i.e. no air bubbles in the casting).

Pulling end-to-end on aluminum causes that type of fracture.

IMHO, the break isn't because of how much power you're putting down.

 

just got off the phone with PST. They've 'reviewed my case' so to say, and have determined that its probably just a bad casting on the yoke and are going to install a new yoke, check the balance and send it back. They paid shipping both ways. +1 for their customer service!

I have the tailshaft back on the tranny. I didnt find any abnormal metal parts in there, nor cracks in the tailshaft... but the tailshaft bushing (metal sleeve where the DS goes in) was all kinds of hacked up, so went ahead and replaced that along with the output seal. the new Timken bushing actually looks to be of a simpled bronze/brass instead of a smooth aluminum like the stocker.

so once i get that shaft back in the car, i just gotta filler back up with syncromesh, get the shifter/console back together and prey the tranny doesnt make any weird noises when i start it back up again.

what an unnecessary headache this has all been... but at least the involved vendors have been very helpful, and i'm only out the cost of a seal/bushing and 4qts of synromesh

 

Thats a good thing, it sucked it broke but PST was smart on stepping it up.

The ONLY thing that could have fucked yea if there was not enough slip travel in the DS in relation to the trans, sometimes DS companies will do that to get out of warrentee.

But either way it work out!