According to JD Powers, back in 1980 more than 35% of new cars purchased in America came with manual transmissions. Depending on source to which you listen, in 2012 that’s down to 5 - 7%. Cars with manual transmissions just don’t sell well any more.

You don’t have to look much further than late model Mopars to see proof of the
dominance of automatic transmission cars in the marketplace. Whole model lines
don’t even offer a manual transmission as an option. Chrysler 300, Dodge
Charger and Magnum, not a one with a stick shift on the options list; the
only late model Mopar V8 you can buy with a manual transmission
option is the Challenger.

Modern automatics are vastly more efficient than they were back in the day. Additional gears, overdrive, lockup torque converters and computers have reduced the miles per gallon gap between manual and automatic transmissions, an important consideration for today’s buyers. But all of this additional complexity is not necessarily good for gear heads and performance enthusiasts.

MoparMax’s 2007 Dodge Magnum SRT8, the Maulin’ Magnum, has been a rolling lab experiment for the last year or so. Fifteen months ago the car was factory stock. Since then it’s had a 50 hp shot nitrous kit, then went back to normally aspirated and the rear end was strengthened and steeper 3.55 gears installed. Then a 150 hp shot nitrous upgrade was installed, then that was removed and a Magnuson Magnacharger kit was bolted on. We’ve experimented with our Diablosport Trintity including the various shifting modes and raising the shift points.

In the process of all this, the Maulin’ Magnum has racked up 49,000 miles and over 400 laps at the drag strip. In fact, as we’re writing this the Magnum is within one round win of first place in its class in two different racing series, PSCA and WCHRA. In other words, she’s been used hard and the data logs started to indicate that the transmission was tired so it was time to service it. We’re breaking this article into two parts, in this first part we’re going to cover upgrading the valve body and in part two we’ll cover the transmission itself and torque converter upgrades.