â€¦driving a fast hot rod is fun, unless it kills you.

MilesnMiles · Post by **MilesnMiles** » Wed Mar 08, 17 10:07 pm

Indeed Paul, I've watched your posts on that.
I'm staying with a lazy legðŸ•

GJUK · Post by **GJUK** » Wed Mar 08, 17 10:57 pm

So the bolt in sprag is an upgrade which stops exploding lower body parts?

Easy fit?

MilesnMiles · Post by **MilesnMiles** » Thu Mar 09, 17 7:37 am

Like this
http://www.aandatrans.com/Departments/C ... Sprag.aspx

Video

They don't just go around blowing up in ordinary circumstances, though.
If you have a habit of blasting the motor up to 6,000rpm in first and not changing up, or burning out in first gear you might have get a problem.

Burn out in second gear.
I manual shift my trans as it changes up too early for a 340 and just missed a gear and must have stressed the trans too far.

Mine ended up like the one in this article
http://www.dodgecharger.com/forum/index ... 107.0.html

Kev · Post by **Kev** » Thu Mar 09, 17 10:34 pm

904 has bolt in sprag from factory?

Blue · Post by **Blue** » Fri Mar 10, 17 6:52 am

Yes Kev, all 904's are bolt in sprag. For the millionth time lets clear up a few myths here. The sprag or overunning clutch is a mechanical device that only allows the rear drum to rotate in one direction. it has a serrated cast iron outer ring that is pressed into the aluminium case. The only reason the bolt in sprag exsists is as a repair part for high mileage transmissions where the sprag has worn loose in the case or has actually spun, it allows you to save a damaged case. The racing industry sell it to you as an upgrade and safety feature, it is no stronger as a unit, the 4 thin bolts that hold it in could still shear off if you abuse it, it is in no way a fix.
When it fails the front drum will instantly accelerate to engine RPM x 1st gear ratio and if it's turning fast enough the cast iron drum will come apart like a grenade, destroying the transmission and sending shrapnel flying in all directions including through the floor.
The only sprag that is actually stronger is a super sprag which is a billet unit and far less prone to spinning or bursting. A billet steel front drum will withstand a lot more RPM before that comes apart and an aluminium unit even more than that, but they are not for street use.
Don't get carried away with the idea you are driving around with an unexploded bomb in the car, they are a strong unit but have thier limits like everything else if abused. Do not do first gear burnouts and if accellerating hard in first gear do not suddenly come right off the throttle and drag the engine down, it is things like that that can damage the sprag and ruin your day. Otherwise forget about it and get a good nights sleep....

GJUK · Post by **GJUK** » Fri Mar 10, 17 8:09 am

Blue · Post by **Blue** » Fri Mar 10, 17 9:35 am

Topspeed list a driveshaft loop on ebay that is a universal fitment, I would always fit one for strip use. Transmission wise, you know what not to do so don't do it and worry about something else instead...

Aitch · Post by **Aitch** » Wed Mar 15, 17 10:41 pm

They don't just go around blowing up in ordinary circumstances, though...or burning out in first gear you might have get a problem.

Burn out in second gear
So what you're saying is only do burn outs in second? As in start in second, or get the wheels spinning in first and then change up?

Blue · Post by **Blue** » Thu Mar 16, 17 6:30 am

Start in second.

mopar_mark · Post by **mopar_mark** » Thu Mar 16, 17 11:26 am

As the subject of 727s Sprags & burnout gear selection seems to continue to be raised, be good if this info could be made a sticky in the Trans area...