Overdriven Excitement - Mega Monster AOD Transmission Installation
With The Help Of Monster Transmission And Performance, Installing An Overdrive Transmission In Your Classic Ford Has Never Been Easier Or More Affordable
From the February, 2011 issue of Modified Mustangs & Fords
By Justin Cesler
Photography by Justin Cesler, Steve Baur
With our '70 up in the air,...
With our '70 up in the air, it was pretty apparent that it could use all the help we could give it. The stock C4 transmission was hardly able to move our Mustang a foot, meaning we literally had to push it into Monster Transmission's shop.
Whether you're a seasoned Mustang modifier or are just now enjoying the ownership of your first classic Mustang, you are probably familiar with one of the golden rules of tinkering: For every positive action, there is usually an opposite and equally negative reaction. Take for instance that new camshaft you have been eyeing. While it certainly will give you more horsepower, torque, and parking lot credibility, it won't do so without costing you a certain amount of driveability or gas mileage. Or, how about a new ring-and-pinion? While a set of 4.10 gears will make getting off the traffic light a blast, the downside is the inevitable loss of gas mileage and the wear and tear of sustaining higher rpm while cruising. Of course, for every rule, there is an exception. In our particular case, we're talking about automatic transmissions, an essential piece of your driveline that can normally be upgraded without suffering any decrease in performance or enjoyment. In fact, with many new cars coming with six-speed manual and automatic gearboxes, it's hard to argue with the theory behind adding gears to any retro ride.
Depending on your exhaust...
Depending on your exhaust setup, you may find it helpful to remove one or both exhaust manifolds prior to pulling the stock transmission. In our case, we removed the passenger-side long-tube header, which gave us much better access to the transmission.
Case in point, our '70 Mustang coupe. Powered by a 302 and a C4 three-speed automatic transmission, the '70 is a real driver, although it has recently sat dormant due to a destroyed transmission. When we went searching for rebuild options, we immediately thought of ditching the C4 for an AOD unit, which could be built just as strong, while also giving us an overdrive gear, allowing for a more modern cruising experience, an increase in gas mileage, the ability to stay in our engine's powerband longer with each shift, and the option to upgrade our rearend gear later, without making our Mustang undriveable on the street. Now, we must be honest, there is one downside to converting your C4 to an AOD and that's the amount of time and money you have to spend scouring the Internet to find the right parts.
Enter Monster Transmission and Performance of Brooksville, Florida, a company dedicated to providing some of the best transmission rebuilds on the market. After seeing a need for simple, turnkey overdrive transmission conversions, the crew at Monster sat down and compiled a virtual nut-and-bolt list of everything needed to complete this swap. With one call to the folks at Monster Transmission, we were set up with everything we needed for the swap, including a 450hp-capable AOD transmission, a new torque converter, a flexplate, a block plate, and all of the required linkages. Inside the Mega Monster AOD, there are a plethora of upgrades, including Alto Red Eagle clutches with Kolene steel friction plates, a one-piece input shaft, and a vehicle-specific shift recalibration kit, which Monster tailored to our exact needs.
Of course, the extra horsepower capabilities of the Mega Monster were a bonus and the upgraded shift feel will make for excellent part throttle and wide-open shifts, but the real magic here is in the overdrive. With a 0.67 Fourth gear ratio, Monster claims customers will see a 30- to 40-percent increase in gas mileage over a C4, which, depending on how much you drive your classic, will basically pay for the transmission in no time. Now, we know you're interested in seeing how this conversion is done, so follow along with us as we equip our '70 Mustang coupe with a Mega Monster AOD. We promise it will be worth the upgrade!
With the header out of the...
With the header out of the way, Monster Transmission's Mark Knapp and Demetri Hazivasillis began the removal of our C4 by first disconnecting the transmission cooler lines, followed by the speedometer cable, the stock shift linkage, the kick-down linkage, and the driveshaft.
After removing the starter...
After removing the starter and stock converter dust shield, Demetri unbolted the four torque-converter-to-flexplate bolts. Mark removed the factory transmission crossmember from the chassis, allowing them to slowly lower the transmission jack and remove our slipping C4.
Out of curiosity, the crew...
Out of curiosity, the crew at Monster decided to tear down our old C4 and find out exactly what was wrong with it. Besides the obviously disgusting transmission fluid, which was barely even filled, we found evidence of extreme wear and tear, along with several burnt up pieces.
With any transmission disassembly,...
With any transmission disassembly, the clutch packs can tell a majority of the story. In our C4, the friction plates, steel plates, and the back plate all showed signs of excessive heat and wear. Obviously, if we were rebuilding our C4, these would all need to be replaced.
Here's our new Mega Monster...
Here's our new Mega Monster HD AOD transmission, laid out so you can see all of the internal upgrades. Rated to handle 450 hp, the Mega Monster includes all new internals, a recalibrated manual/automatic valvebody and valve plate for shift firmness, and a high-performance shift improvement kit.
The Mega Monster AOD also...
The Mega Monster AOD also comes with high-performance Alto clutch packs for the direct, intermediate, and reverse clutches, which include Alto Kolene steel plates and the tried and true Alto Red Eagle friction plates.
In order to install our new...
In order to install our new Mega Monster in place of our C4, we had to change several of the exterior linkage connectors. On the left, you can see the factory gear selector linkage, which we replaced with the correct linkage on the right. Don't worry, everything you need can be ordered from Monster for a quick and easy install.
The AOD transmission also...
The AOD transmission also requires a new block plate and flexplate, both of which come in the conversion kit. Note the quality aluminum two-piece design of the block plate, which allows for easy access to the torque converter.
As you would expect, the block...
As you would expect, the block plate and flexplate bolted right on to the back of our factory 302. For the majority of installs, a 28-ounce imbalance flywheel will be necessary, but you could also order a 50-ounce flexplate if you're running a newer 302 ('81-'01). Make sure you install the correct one; you don't want to have an issue with harmonics!