Alum vs Steel Drum
 

Need your help! Do you think there is alot of Et or MPH change with a steel or alum drum(5 Clutch pack) in a 2 speed? SS/ 275hp 327chev. We killed a new Ati alum in one pass! Thanks, Ron

Re: Alum vs Steel Drum
 

An aluminum high gear drum makes a measurable difference in a Powerglide, especially in a small block car. If you hurt a new ATI part, call them, they'll make it right if it is their fault.

Re: Alum vs Steel Drum
 

Thanks Alan, I will call them and see what they say. Just haven't had luck with warr parts. It was the new one with the steel insert. May have to put the old Ati back in for the next race.

Re: Alum vs Steel Drum
 

I found no difference when I went from the aluminum drum to the steel drum. I used the Coan lightened steel drum in one trans. That worked real good. I have a stock one in the trans I have I the car now. What happened to the drum that just tore up?

Re: Alum vs Steel Drum
 

It was torn up bad, like the band wasn't releasing in high. All we did is replace it with a new band and steel drum and cleaned the trans and it was great. ATI won't call back after a few messages left.

Re: Alum vs Steel Drum
 

What band did you use with the aluminum drum? What was the band adjustment procedure?

Re: Alum vs Steel Drum
 

My trans guy did that but I thought it was 3 and 3/4 out, and the red band.

Re: Alum vs Steel Drum
 

I always used a red band and ran the band at 3 1/2 turns from snug. I had some problems with a front pump that was not giving me enough pressure and was eating bands and drums. You need at least 170 lbs of pressure according to Coan. I use a Kevlar band on the steel drums. I would only use an aluminum drum if you are trying to get that last .001 or .002 to set a record or a class run situation. The steel drum does not leave the gray mess in the pan either. The lightened steel drum from Coan is a good alternative.

Re: Alum vs Steel Drum
 

Any idea how much? Does he keep them on hand?

Re: Alum vs Steel Drum
 

I have used both and the aluminum drums don't hold up especially in higher rpm applications. On the other hand the lightweight steel drum from Coan worked great...the problem is they no longer make it. I called 2 weeks ago because I couldn't find it on their website anymore and was told they couldn't get enough steel drums to make them but if you have 10 drums you could send them in and they might would machine them. So there is an option to get them made.

Re: Alum vs Steel Drum
 

Yep, got the same answer when I called. Anyone have one they want to sell?

Re: Alum vs Steel Drum
 

Just some info................

I was told by Marv Ripes from A-1 about 40 years ago to NEVER, NEVER, NEVER shift into Low Gear with the car moving.....

Over the years I have built a lot of Power-Glides and I always tell the driver to never shift into Low Gear with the car moving......

There is no dynamic load on the band during apply so there will be no marks on the drum from the band stopping it's rotation....

It's easy to see on a freshen who listened and who didn't......

One more thing is to use only Teflon type rings on the aluminum drums to keep from scoring the bore....

Hope this will lengthen the life of your drums,
Bob

PS:

While I am at it:

I see a lot of drivers with 3 speed A/T's while rolling backward in reverse rather than step on the brake and bring the car to a complete stop they just put it into Low Gear and drive away.........

The only trouble with that you take a static apply clutch pack (the forward clutch) and turn it into a dynamic clutch pack and that is not what it is designed to do.....

We beat up on our parts with horsepower that the factory did not have in mind when they designed them, so anything that we can do to reduce the wear and tear will end up as extra life....