Torque Converter Tech Tips
- Author: Ed Lee
Many late-model Honda converters have unique stator bearings. The caged-roller part of the bearing is like the bearing used in the JATCO RE4R01A converters. This part of the bearing is not unique. The outboard races of the stator bearings also are not unique. The impeller-side bearing runs against the flanged impeller hub, and the turbine-side bearing runs against the turbine hub. It is the bearing races on each side of the stator that are unique (see Figure 1).
The 0.080-inch-thick races have four tabs that keep them from rotating and four slots for oil flow. The inside diameter also has a 0.035-inch lip to keep the caged-roller part of the bearing centered. The impeller-side and turbine-side bearing races look the same but perform different functions. The race on the impeller side does the traditional job of carrying thrust loads during acceleration. The race on the turbine side, on the other hand, has to do double duty. One duty of the turbine-side bearing race is to carry thrust loads during deceleration. The second duty is to retain the one-way clutch in the stator assembly. The four-tab race sits on top of the aluminum stator cap and is held in place by a retaining ring (see Figure 2).
The caged-roller section of the bearings is available through the aftermarket, but to date the four-tab race is not, through either the original-equipment manufacturer or the aftermarket. To make things worse, some of the older Honda converters that continue to be manufactured today have been upgraded to this new type of bearing. The Dacco HO-12 and HO-16 are good examples of this. The converters with the upgraded bearing are identifiable on the outside because the impellers flare out more where they meet the ring gear (see Figure 3), and the converters with the early-style bearing flare out less (see Figure 4).
On the inside, the converters with the upgraded stators and bearings will have only three stands on the turbine where the turbine mates to the damper assembly.
Roger Weaver of Landis Converters in Leola, Pa., has found a way around the lack of replacement bearings. He uses a bearing from the overdrive section of one of the rear-wheel-drive Chrysler overdrive transmissions, such as the A500 or A518. The bearing is on the overrunning-clutch hub and separates the clutch hub from the output shaft. These bearings are available through both the vehicle manufacturer (part number 1-04461014) and the aftermarket (Sonnax part number MI-N-28). The replacement bearing is about 0.008-0.009 inch thinner than the OE bearing, but this does not appear to affect performance.
Roger machines the inside diameter of the bearing cavity in the stator to fit the outside diameter of the replacement bearing. You are machining only about 0.025 inch of material from each side of the bore. Make sure the relief that is cast into the bottom of the bore remains open for oil flow. Roger replaces all of the impeller-side bearings and has a surplus of good races for the replacement of the turbine side if necessary. Remember that the turbine-side bearing race is also the retaining plate for the one-way stator clutch and cannot be replaced like the impeller- side race as described in this article.
Special thanks to Roger Weaver for sharing his unique idea.
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. ©2007 Sonnax Industries Inc.
