seat problems on a 129 FYI

does anyone know of a repair kit or a place that repairs the gears rather than replacing the whole gear assembly.  Thanks....  After closer examination it wasn''t the gears that were the problem.  For once an inexpensive fix on an sl.  If you have a problem with one side of the rear of the seat not going up or down check for play in the flexible drive shaft between the motor and the gear assembly.  There should be a shim between the shaft and the gears so there is no back and forth movement in the shaft, but no tighter.  I used a regular faucet washer. I modified the hole in the washer to fit snug on the gear shaft.  Do not use a metal shim.  It works like new.  If you look at the flexible shaft and the splined caps at each end of the shaft and how they can come slightly apart during operation of your seats you will know the necessity of the shim.