298 mm Identification

298 mm IDENTIFICATION

GM - Torque Converter Identification is easy once you know what the I.D. codes mean. Although each digit of the four digit code has its own meaning, the valve of each code letter or number is different for 298 mm and 245 mm torque converters.




Look at the I.D. code in figure 1. The torque converter in figure 1 is 298 mm in dia. The first digit refers to the application. See figure 2.

B = 250 and 350 Transmissions
C = 200/200-4R 325-4L Transmissions & Pre 1985 700-R4
D = 1985 and later 700-R4 transmissions with the 30 spline input shaft

The second digit refers to the "K" factor. The "K" factor is an engineering term that means the speed of one member divided by the square root of the torque on the same member.' This is calculated at stall conditions. On a 298 mm torque you can multiply the "K" factor by 14.2574 to get the stall speed. Use the chart for a quick reference.

"K" FACTOR STALL

A = 142 = 2024
B = 140 = 1996
C = 135 = 1925
D = 130 = 1853
E = 115 = 1639
F = 110 = 1568
G = 100 = 1425
H = 97 = 1383
J = 89 = 1269
K = 85 = 1211




The third digit refers to the clutch type, capacity & travel in degrees.




The fourth Digit (optional) refers to the cover style, the number of mounting lugs & the method of welding the lugs.

Look at the I.D. tag on the torque converter in figure 1. It's easy to see that it fits a late 700-R4 with the large input shaft (the first digit is a "D"). It has a 1996 stall speed (the second digit is a "B")

It has a damper assembly rated at 300 ft/lb. of torque and can twist 44 degrees (the third digit is an 8). Finally it has three lugs with 180 degree welds on each lug and belongs in a diesel (the fourth digit is a "D").