Moparts Tech Archive
Aluminum Drum 727?Some Car Guy
From: sometown in KY
Registered: Nov 2001
posted 07-03-2002 04:22 AM
I have read for awhile that the aluminum drum from A and A trans is a great piece. Increased safety and decreased ET's. At what point do you need to think about running this piece? Also what other upgrades should be considered for a 500-550 hp street strip car. I'm not talking about deep pans and coolers, I'm talking hard parts. Thanks
My racing years have covered motors that produced power from 550 to 800 HP, and the real problems start at about 600HP and /or the use of a transbrake. Then the trans needs to be rollerized to keep from tearing up stuff. Also thier are mods for the outputshaft support to keep it from gauling at over 550 hp level. On the aluminum drum, it is very maintanace intensive, as the aluminum comes off the drum from use, filling the tranns fluid with very fine aluminum particles. Fluid needs to be drained about every other race, and the band for second gear needs adjustment every twenty to thirty passes. Too bad nobody makes a Billet steel or forged drum, as they would be a lot better deal. I say just use very good safety equipment, and NEVER use low gear for starting burnouts, and if you ever have a driveline failure, pull the trans and check the sprag. You can't tell if it will fail after a rear end breaks just by driving it. It will fail at full load! The ET reduction is small for the aluminum drum, from .03 or so to less for the faster cars. A local trans builder Has set me up for a fully rollerized trans with all the little tricks to make it live.
Also, A&A has them, but pretty expensive.
Try JPT Transmissions for aluminum drums also, plus good tranny advice. He does rollerized components at a decent price.
Another area of weakness is the front planetary spline. It ia aluminum, and if stressed too much can strip. Some racers use the steel front carrier if using N2 or transbrake. A&A sells these as well. Use a 4 or 5 clutch front drum, a 3.8 or 4.2 lever, a good reverse manual VB, Turbo Action or Griner Engineering.
Roller bearing conversion is big bucks. You can buy the Turbo Action rear roller support and install it very easily. This would help some. www.turboaction.com
I got my 904 parts rollerized at JPT. I sent him all the internals. He charged me $350. Plus he lightened the sun shell and low/rev drum a little. John
ATI sells a 727 with a billet steel drum I don't know if thay have a web site or not. and greg I think thay sell the drum seperat hope it helps O by the way when you install a bolt in spreg 1/4 in ferels from copper fitting make good spacers on the bolts
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