Allison® 1000 Converter – Identifying After the Rebuild

Since the Allison 1000 converter was first introduced, it has been manufactured in four configurations designated: TC-210, TC-211, TC-221, and TC-222. Each configuration has a different stall torque ratio and “K” factor, resulting in four different stall speeds.

Because engine performance is directly influenced by these critical factors, it is important to have the correct combination for each application. A combination that produces a stall speed that is too low will be more noticeable than a stall speed that is too high. The driver of a vehicle with too low of a stall speed will experience a sensation like the TCC clutch is dragging, or will feel an off idle hesitation because the turbocharger will be spooling up at a slower rate.

Before an Allison 1000 converter is rebuilt for the first time, it is easy to identify because the ID barcode, part number, and identifying color code are all visible on the cover. There are two previous Sonnax articles which help identify the Allison 1000 Converters: Which Generation of Torque Converter? Identification Tips For Allison Torque Converters and Allison 1000 Converters: The Next Generation (#6). Since that time, new part numbers have been introduced. See Figure 1 for a complete updated listing.

Identifying the Allison 1000 converter after it has been rebuilt for the first time is more challenging. Sometimes the markings used to identify the converter are removed during the cleaning process or covered up during the painting process. Sometimes the cover gets replaced and the replacement cover does not match the application, or maybe the cover is replaced with an aftermarket billet cover for performance reasons.

In all cases, stall torque ratios, “K” factors and resulting stall speed were originally achieved by combining two different impellers with three different stators. It is easy to misidentify and mismatch these components because all of the impellers have 31 vanes and all of the stators have 20 vanes. The secret in the identification process is to observe the exit angles of the vanes on both the impellers and stators.

Look at the inside of the impeller and observe the exit angle of the vanes at the 12 o’clock position. You will see that on the medium stall impellers used with the TC-210 and the TC-211 converters, the vanes come straight up toward you. On the low stall impellers used on the TC-221 and the TC-222 converters, the vanes angle off to your right. Also notice that a reinforcing rib runs down the center of the vanes on the TC-221 and the TC-222 impellers.

Identifying the stators is very similar. Place the stator with the impeller side facing up. Look at the exit angle of the vanes at the 12 o’clock position. If you think about what happens to the oil as it exits the vane, it will help you understand how this action affects the stall. On the stator for the TC-210 converter, the exit angle of the vane is almost flat and the “window” between the vanes is minimal. This directs a large portion of the oil passing through the stator toward the impeller in its direction of rotation, assisting its movement. This helps to increase stall speed.

The TC-211 and the TC-221 converters use the same stator. On this stator the exit angle of the vane is not as flat as the TC-210, and the window is only slightly larger. As the exit angle of the vane is directed more towards the person viewing the stator, less of the oil is directed towards the rotation of the impeller, therefore, assisting it less.

In the TC-222 converter, the exit angle of the vane in the stator is even straighter up and the “window” is even larger. Much less of the oil passing through the stator is assisting the rotation of the impeller, causing lower stall.

Figures 2 through 5 show the proper combinations for the TC-210, TC-211, TC-221 and TC-222 converters.

Figure 2: TC-210	Figure 3: TC-211
Figure 4: TC-221	Figure 5: TC-222

Ed Lee is a Sonnax Technical Specialist who writes on issues of interest to torque converter rebuilders. Sonnax supports the Torque Converter Rebuilders Association. Learn more about the group at www.tcraonline.com.