Questions about the 10R80 converters are becoming more common. The most frequent discussion is with respect to clutch preload, instead of end play; as matter of fact this unit requires quite a lot of pre-load. Would you believe it needs 70 lbs. (31.75 kg) of force applied to the cover while welding. So, if the clutch is under preload, how does converter charge oil get past the turbine/clutch to the front area of the converter?

Maybe there is enough “flex” in the turbine to allow the clutch to be pushed off the surface of the impeller and allow oil flow? This required a deeper dive into the system. A virgin core was procured with the number HL3P-AD. Preliminary information was collected before cutting the converter open. I recorded an overall height of 4.890” (124.21mm) and noted the turbine had no endplay and a slight resistance when turned with a pair of snap-ring pliers. Torque to turn was estimated at 24 in. lbs. (2.71 Nm) of torque, and the stator had 0.100” (2.54mm) of clearance. This only applies to the HL3P model and not the JL3P code converter used mainly in Mustangs or the 8F35 converters. After cutting, cleaning, and stacking the converter, I re-measured the assembly without welding it. The overall height and the stator clearance were within 0.005” (0.13mm) of the original measurements.

The core was in particularly good condition; including the clutch lining and impeller reaction surface. To determine what the turning resistance of the clutch turbine assembly would be with 70 lbs. (31.75 kg) of force applied; the first step was to make an input shaft to turn the input splines with the converter assembled (figure 1). I used a 1 1/8” (28.58 mm) diameter shaft, ground back 2 splines on one end and a welded a 7/8” (22.23mm) hex on the other for a socket. The turning resistance with only the weight of the impeller was just under 24 in. lbs. (2.71 Nm) (figure 2). Adding 70 lbs. (31.75 kg) of force to the cover, while turning the turbine was the next challenge. A couple of old face plates were located and placed on the crown of impeller with the impeller facing up. A 48RE lockup piston was added to the stack to reach 70 lbs. (31.75 kg) (figures 3&4). The resistance was now 12 ft. lbs. (16.25 Nm). This was with a used clutch and a lightly oiled reaction surface. This will deviate some; with a new clutch and re-surfaced reaction interface. Since this was sample size of 1 converter; the results of the average turning resistance range is yet to be determined.

The angles on the clutch and reaction surface are interesting. The geometry on my core did not agree with the numbers that I received from another shop. After checking against another core; I found those values to align with the information I have received from the other shop. See the table below.

Unless it is the result of bond tooling and turbine surface variation or impeller to turbine variation in the stamping process; they all have a subtle difference between the impeller and the turbine angles. This might suggest the outer portion of the friction material contacts the reaction surface of the impeller first for a progressive clutch apply.

I measured the turbine/clutch with the lining still on the turbine. While this was not the most accurate way to gather data; I settled for doing it this way to keep a good core intact. The angles were measured by putting the impellers on a face plate mounted on a lathe with a DRO; then placing a dial indicator on the saddle. I touched off and zeroed the indicator on the high side of the angle and also zeroed the DRO on both the X and Z axis.

The cross slide was advanced 0.500” (12.7 mm) along the X-axis, and then the saddle was advanced along the Z-axis until the dial indicator returned to the original zero. This gives the length of the 2 sides of an imaginary right triangle 0.500” (12.7 mm) and 0.172” (4.4 mm). The result in this case is 18.98°. I measured both the impeller and the turbine in 4 places at 90-degree increments and averaged the results to get a final measurement. This could also be done on a mill. Just make sure that the measuring point is on an axis that goes through the center line of the impeller or turbine.

The clutch facing has worm tracks embossed into it; creating an intentional leak path for oil to pass from the OD to the ID of the clutch facing. The OEM facing measured 12.03” (305.5 mm) x 10.87” (276.1 mm) x 0.040” (1.0 mm). It is a 3-piece segmented puzzle lock lining, and it was noticed that the joints are slightly separated on the ID of facing after it was bonded (figure 5). This is most likely from forming a flat facing on a convex bond surface. The facing has a total of 9 sets of worm tracks that appear to be pressed in during the bond process. The worm track grooves are 0.008”-0.010” (0.2 – 0.3 mm) deep x 0.050”-0.055” (1.3 – 1.4 mm) wide. Each groove covers approximately 4.5” (114.3 mm) of length if the zigzag pattern were to be a straight line. Because most available facings do not have any grooves; an alternative is to press them in during the bond process. This is tricky at best from both an alignment and available tonnage perspective. Pressing the groove in hot is your best opportunity to form the grooves into the facing, but most commercially available bond stations cannot supply the tonnage to both compress the material in the groove area and provide a satisfactory bond across the facing.

When bonding these pistons all the normal rules apply for surface prep, cleanliness, bond cycle, and geometry. The top and bottom die alignment would be more important than when bonding a flat clutch; to ensure that there is uniform pressure applied across the loose facing. To preserve the rigidity of the bond surface, I suggest removing the old facing either chemically or with abrasive to maintain the clutch thickness and rigidity. A combination of reducing the friction material with a cutting device, to just above the bondline, grit blasting to remove the remainder, and then washing and flushing the assembly of contamination will yield the best bond surface without reducing steel from the turbine.

Part 2 will look at information on the unique dampener assembly used in these converters and welding procedures. I encourage you to reach out if you have any thoughts, questions, or opinions on the 10R or 10L units. I can be reached through the TCRA forum, TCRA’s Facebook Group, by e-mail, or Phone through the forum or Facebook page.

Brad Gilbert
TCRA Technical Coordinator