kyle-22r,
Unfortunately, the only upgrade, besides always blueprinting the trans, is installing maximum input and output bearings. I always keep a set in stock.
The draw back is that there is no room to increase the bearing bores, and more important, the 19 mm countershaft center pin could not of been increased without a major trans redesign.
Instead of inproving the L43, Aisin Seiko [the manufacture] discontinued the trans that was built from 1971 to 1980. 71' to 74' L42's used a 17 mm pin, 75' to 80' L43's got the improved 19mm centerpin. On a side note, the 2wd boxes, used bronze countershaft bushings instead of the longer lasting 4x4 style cage bearings.
One of the most important measurements, to make the L43 stand up to the task, is to keep the countershaft end play to .005" to .008". When the gears are allowed run out of line, failure is certain
Marlin
