When we took delivery of project Stealth Bomber, the '89 Diplomat police car, we set a goal that would require a fairly stout drivetrain. The first item on the agenda is the transmission. Even though the mileage was remarkably low, the 58,000 miles showing on the odometer were hard miles. The shift quality wasn't great, resulting in early and soft shifts. This, as well as lots of overlap, and a propensity for freewheeling in reverse until the car was good and ready to move, told us it was definitely time for a rebuild. Normally, we would lean towards the more bulletproof 727, especially in a drag application where repeated hard launches take their toll, but in this situation the A999 derivative of the venerable 904 was deemed more than adequate. Remember, our stated goal is a 150-mph capability, so we will maintain the ultra-high 2.94 rear gear, and upon launch the car will not be subjected to much shock. The '89 A999 our police car was equipped with is a wide-ratio transmission featuring a 2.54:1 first gear ratio, a 1.54:1 second gear, and a 1:1 high gear. An autopsy revealed burned high-gear/reverse clutches from overheating, burned bands, and a slightly-mangled, lower/reverse drum thrust-washer. We were fortunate that our 'Flite didn't require any "hard parts," as everything internal was serviceable.
 Here it is, an A999 wide-ratio,...  Here it is, an A999 wide-ratio, 3-speed automatic--slightly used, a bitgrungy, but perfectly serviceable. |
 TransGo provided us with a...  TransGo provided us with a shift kit to help firm up the shifts on ourworn-out A999 trans. This kit covers all 904 Torqueflites and theirderivatives, including the A500 four-speed, automatic-overdrive units.Included with the kit was this video that shows you how to install thekit from start to finish. It proved invaluable. |
 Once all the mounts, linkage,...  Once all the mounts, linkage, and brackets are removed, then remove theplate on the tailshaft housing that covers the snap ring. Having access,open the snap ring and lift the tailshaft housing off. |
 With the pan out of the way,...  With the pan out of the way, the valvebody is now accessible and can bedetached with 10 torx-headed bolts. Hopefully, you drained the transprior to removing the pan! |
 With the six bolts holding...  With the six bolts holding the front pump in place removed, you willneed a slide hammer to actually take the pump out of the case. There aretwo 3/8-inch coarse-threaded holes, 180-degrees apart at the 11 and 6o'clock positions (approximately), made specifically for the slidehammer. After the pump is out, you can now remove the input shaft bygrabbing hold and pulling--as long as the forward clutches aren't weldedtogether. Thankfully, ours weren't. |
 In order to remove the spring...  In order to remove the spring from the high-gear/reverse clutch drum,you will need a good spring compressor. The snap ring needs to beremoved first. Be very careful while performing this task because thespring is under a lot of pressure. Our high-gear/reverse clutches wereburned up. With the entire transmission apart, it's time to assess thedamage. Fortunately, we had no "hard part" damage and would only have toperform a "soft part" rebuild. |