Just refreshed the Heisler OD on my 1936 F20. The input seal was leaking in a major way, and since I was going to go in there anyway I decided to replace the bearings as well.The seal was an ancient CR (Chicago Rawhide (real rawhide)) seal, and had rusted to the input seal surface. The sleeve the input seal surface rides on had corroded badly, and I could not locate a replacement. The bearing house representative said he had never seen anything quite like the input gear, bearing, and sleeve set-up the Heisler had. I had to work the sleeve over well and fill pits in the surface with JB weld. It worked out really well. If your sleeve is beyond recovery perhaps one of those thin and handy axel seal savers could be used. Be advised the sleeve is a press fit to the input shaft/gear. The following are the original bearing numbers and the replacement seal number. Running these past a good bearing house prior to disassembly will reduce the anxiety associated with refreshing your own unit as well as speed things up. You’ll also need to replace the 6 tiny (about .185) ball bearings that hold the sliding gear in high or low range. The bearing house easily fixed me up with replacements for these worn detent balls. Make sure you tighten the four mounting bolts inside the housing that hold the OD to the transmission as well as the two outside on top of the unit. Input bearing New Departure 5207; Countershaft bearings ND 3304 and ND 3204; Input seal (TCM brand) 16253TB-H. I ended up making new gaskets for it but the unit is free from leaks, is quiet, and works like new. Good luck, Scott in SC
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