Changing Converter Designs Change Your Approach
The 10-inch front-wheel-drive Chrysler converter used in the 604 and 606 (41TE & 42LE) transmissions has undergone some changes in recent years. From the outside you can see that the surface of the impeller, smooth on the earlier models, now has dimples (see Figure 1).
2002-Up 5R55N/S/W Converter Noise: One Shop’s Solution
Converter shops around the country are seeing an increase in complaints about the late-model 5R55N/S/W converters; more specifically, the noise they make. These noises are described as a clattering sound, often compared with the sound made by the early E4OD multi-clutch converters. The sounds seem to be made by metal-to-metal contact, and all disappear when the TCC is applied.
Identifying the 722.6 Converters
Mercedes has used the 722.6 transmission in a number of different vehicles and in combination with different engines. To accommodate these different vehicle and engine combinations, different converters were needed. Many of the converters were similar in appearance and differed only in their bolt circle or diameter.
Water Contamination in Torque Converters
Opening up a torque converter and finding what looks like a strawberry milkshake inside is fairly common in the rebuilding industry. The strawberry-milkshake appearance is the result of ATF being contaminated by water. A small amount of water mixed with transmission fluid will change the appearance of the fluid dramatically. Since many shops have limited areas available for storing cores, some cores are open to the elements. Transporting cores in open vehicles also increases the opportunities for water contamination.
A Different Fix for an Old Problem
The problem of bore wear on torque-converter-clutch pistons has been around since lockup torque converters were born. The rotational restriction on the pistons is handled by splines, pins or fingers. But centering the pistons is generally the sole responsibility of the bore. Any out-of-balance movement of the piston will cause the piston bore to scuff against the turbine hub when it moves to apply or release the clutch. Indexing the piston to the turbine and balancing this unit helps minimize bore wear. (See the article on indexing TCC-piston damper assemblies to turbines, Transmission Digest, March 2006.)
Getting Your Cores Back
When torque converters first transitioned from the early bolt-together units to the welded/sealed units of the present day, transmission shops were faced with a new challenge. Most customers weren’t willing to pay for a new OEM converter on top of the cost of a transmission overhaul. The only alternative available at that time – reusing the customer’s original converter – seldom saved the customer or the transmission shop any money. More often than not, reusing the original converter created new problems when contamination from the original failure entered the newly overhauled transmission.
4R100 Flow Issues
The 4R100 has come by its flow problems honestly. It has inherited them from the E4OD.
Time to Change an Old Habit
Our industry is reporting an increasing number of converter leaks that are coming from this area. The normal stresses that are being exerted on the converter during acceleration – plus the extra stress of lockup apply – are causing the converter to flex. And the culprit is the sharp angle at the edge of the lockup surface (see Figure 1), which creates a flex point for a crack to start.
A Fix for 5R55W Front-Planet Bearing Failure
The 5R55W transmission was used in Ford Explorers and Mercury Mountaineers from 2002 through 2004. This unit is very similar to the other 5R55 series transmissions, but each model has a few unique differences.
Indexing TCC-Piston/Damper Assemblies to Turbines
At a recent TASC™ Force meeting, one of the members expressed concern about an increase in the number of worn-out bores in TCC pistons that he was seeing. Although the problem is prevalent in many different pistons, his main focus was on the GM 298mm pistons.
RL4FO2A/RE4FO2A: Mysterious Axle-Seal Leak
A 1993 Nissan Maxima was brought to a transmission shop. The customer complained about a persistent transmission leak that was leaving a spot on his garage floor and said the transmission had been rebuilt about a year earlier. He added that the vehicle was returned to the original shop within the first month to have the passenger-side axle seal replaced. Since the axle-seal replacement did not eliminate the leak, the vehicle was taken to a general-repair shop, which replaced the axle seal and installed another axle under warranty. The customer said that each time the vehicle was worked on, the leak seemed to stop for about a month, then reappear.
TCC Apply Piston & Cover Deflection
A 604 transmission with a 740 code led to many different approaches and attempts to troubleshoot the underlying problem. As the possible causes were narrowed down, the focus began to turn toward the converter. Replacing the converter with a factory unit eliminated the 740 code, and since the code would show up on any road test, this seemed like the perfect vehicle to identify the root cause.
