[72 Challenger (Hans)]

Is there anybody around here who has experience with transmission shields or blankets ? If so, how/where do you apply these things and what's the better; shield or blanket. I hope to run 11's next year w/ a 440 running 7000rpm so a bit of safety thinking is in it's place imo. Any opinions about it... thx Hans

[dave-r]

Firstly. Buy that transmission book that Blue refered to me. I don't have it to hand at the moment but can give you th edetails if needed.

Trans explosions are caused by a failier of the one-way overrunning clutch at the rear of the trans.

If it fails the front clutch drum spins at twice the speed it should do. The cast material the drum is made of cannot sustain this speed for very long and it explodes.

A trans blanket or shield will help contain that explosion. BUT! A blanket can increase the temp of the trans (they say) and a shield can be difficult to fit in a stock trans tunnel.

Another route is to prevent the explosion in the first place.
A bolt-in over running clutch is MUCH stronger and is less likely to fail.
A alloy front drum will take the high speed spinning if the clutch does fail.

These parts are expensive. But not as much as a new trans or leg surgery.

[72 Challenger (Hans)]

So there won't come a shield then as I will not modify th trans tunnel. It's maybe a better idea as you said to prevent the trans explosion by installing another front drum. But then a billet steel one instead of the alloy, the alloy one wears out way to fast on a street car. And offcourse when throwing in a manual valve body I should go with a "low band apply / engine braking" body. Will see for the book. Thanks Dave.

[dave-r]

There may be a shield that requires no tunnel modification but I have heard "bolts straight in" so many times lately I have come to understand the phrase is really an abreviation of "bolts straight in third time after lots of cutting, drilling, hammering, and swearing."

Yes a steel drum sounds the right choice and a manual valve body will apply the rear band.

I might be tempted to try a trans blanket and see if the temp really does increase.

[72 Challenger (Hans)]

That "just bolt it in"... Been there done that. First seeing, then believing!

About the valve body, most popular manual valve bodys (Turbo Action, TCI etc.) doesn't have the low band apply. So when you floor it, release it and floor it (the accellarator pedal) the sprags get all the knocks which gives a chance on braking it. So I better go with a griner or pro trans valve body which have the low band features.

And even with an explosion the leg that will get hurt is the right one, just the only power adder the car has! Better go for safe.

[transman]

I don't know what the rules are over there, but here in North America, the NHRA and other bodies determine the need for some type of protection from a possible transmission or converter expoloding problem. I have a customer that runs in the 10.90 class, and he is required to run some sort of shield. Check with your governing racing body to be sure.
Yes, do not use an aluminum drum on a street car, as the drum will wear out very quickly. Another note, do not use a kevlar lined band on an aluminum drum. It has been our observation and experience that the only place one should use a kevlar band is on a steel or cast iron drum.
All aluminum drums by the way are a high maintenance item.
Transman