Most Mustang owners know there is a certain allure to banging gears with a manual transmission. Still, people like to race cars with automatic transmissions-and for good reason. There are no missed shifts, less chance of breakage, and in general, the vehicles are more consistent than ones with clutches. If you're starting out with your old, tired AOD transmission, however, you've probably found that gear changes are slow, and getting your Mustang off the line in a fast manner is futile. Performance Automatic in Gaithersburg, Maryland, however, can turn your AOD into a timeslip-eating machine.
Performance Automatic has been a staple in the racing industry as well as supporting street enthusiasts, and the staff knows what it takes to make the automatic transmission in your Mustang work to the best of its ability.
Performance Automatic's Pro...
Performance Automatic's Pro Launch 10-inch torque converter (PN PA53203) retails for $838.28.
Lately, we've been modifying a '93 Special Service Package 5.0L Mustang here in MM&FF, and we've done well improving horsepower, dropping seconds from our quarter-mile elapsed time, and improving the fun factor tenfold. The SSP already had 3.73 rear gears when we started the project, so we were able to get the car moving out of the hole quicker than stock. But to put the engine in its peak torque powerband for harder launches and quicker acceleration, we needed a higher-stall-speed torque converter, so we called Performance Automatic for help.
A week later, we had one of PA's Pro Launch 10-inch converters sitting on our shop floor and our SSP raised on a lift, poised to receive it's new performance part. PA's Pro Launch 10-inch converters are specifically designed for modified engine applications with more compression, supercharging, and/or nitrous oxide injection. Stall speeds are increased 1,000-2,000 rpm over stock, and PA specifies the use of an aftermarket cooling device for the transmission fluid when this line of converters is used.
PA's Pro Launch line of torque converters are balanced and furnace-brazed, and utilize needle bearings and anti-ballooning plates for a long, reliable life. Stall speeds usually range from 3,000-4,200 rpm depending on the application. Our particular unit is a non-lockup torque converter, which means that our cruise rpm will be raised by 300-400. The tradeoff is that we'll end up with a much stronger converter in exchange for the reduction in fuel mileage. When it comes to drag racing, however, we've seen great results with aftermarket torque converters, and Performance Automatic's unit didn't disappoint.
The first step in swapping...
The first step in swapping out the converter is to support the transmission. We happen to have a trans jack, but a floor jack will work if you're using jack stands in the garage. Summit Racing and Harbor Freight also carry transmission adaptors for your floor jack so your slushbox doesn't slide off the jack.
Installing a torque converter isn't the easiest job, but it can be done in your driveway. We took advantage of our in-house shop and two-post lift, as it is easier on the back, and easier for us to get pictures for you. Basic hand tools can be used, but air tools make the job easier and faster.
Post installation, the higher stall speed was easily noticeable, and we hustled the SSP to the local quarter-mile track in Bradenton, Florida, to see if our e.t.'s had improved. Prior to the PA torque converter installation, our '93 notchback ran a best e.t. of 13.12 seconds at 106.76 mph, and we backed that up with a 13.20 at 106.42. This was achieved by powerbraking the engine to about 1,800 rpm and then flat-footing the throttle.
With the higher stall-speed, we were able to bring the engine rpm up to 2,600 rpm before matting the gas. Our 60-ft times dropped from a previous best of 2.01 seconds to 1.75 seconds, and the quicker short-time netted a new best e.t. of 12.80 seconds! We backed that up with a hot lap of 12.91-both runs came at a slower 103 mph. No doubt, the slower speed was due to the extra slip, but we gladly traded the reduced mph for the dropped e.t., which is what everyone is after.
The transmission fluid lines...
The transmission fluid lines are next. Use a line wrench if you can get one, as it will prevent stripping the fittings. It doesn't hurt to soak the fittings with a penetrating oil prior to loosening them either.
The shift linkage assembly...
The shift linkage assembly is removed next.
The speedometer cable is next....
The speedometer cable is next. Remove the 12mm bolt and carefully wiggle the cable out.
Be sure to inspect the speedometer...
Be sure to inspect the speedometer gear for excessive wear, and replace it if necessary.
Next, remove the dipstick...
Next, remove the dipstick and start taking out the transmission bolts.
Finally, you're halfway there....
Finally, you're halfway there. Be careful not to snag any wiring harnesses, cables, or lines as you drop the transmission from the vehicle.
You need to check to make...
You need to check to make sure the new torque converter bolts, like the ones that came with our new converter, will fit the flexplate. If they don't, you'll need to drill out the holes with an appropriate sized bit.
Grease the back of the converter...
Grease the back of the converter where it will mate with the pilot bearing/bushing, as well as the front side that connects to the transmission input shaft.
The transmission input shaft...
The transmission input shaft should be greased up as well. The factory two-piece design is long considered to be the weak link in the AOD transmission, but it should be fine for our current power level.
Secure the transmission before...
Secure the transmission before removing the old converter, otherwise the shift in weight could send it sliding off the jack.
Here you can see the difference...
Here you can see the difference between the stock 13-inch torque converter (right) and the new unit from Performance Automatic (left). The smaller 10-inch design will spin more easily due to the reduced mass, which will allow the engine to accelerate faster.
Lightly lube the pilot bearing/bushing...
Lightly lube the pilot bearing/bushing with a high-temperature grease.
After priming the torque converter...
After priming the torque converter with 1 quart of fluid, lift it up and onto the input shaft. Then you need to push and spin the converter simultaneously to get it to seat onto the transmission. Once you hear two clicks, you should be good to go.
The higher stall speed allows...
The higher stall speed allows the little 5.0L to leave the line at a much higher 2,600 rpm, which has translated into low elapsed times at the dragstrip. We've got more in store for our dutiful SSP Mustang, so stay tuned.