I have a 1980 cj7 with a 258 in-line 6 and a 4 spd. standard trans I think it is a borg warner sr4, dana 300 t-case and when I accelerate form a stop I here a pendulum like clanking sound. same when shifting into 2nd and 3rd but quiet when shifting into 4th. Has anyone ever heard this before or what would anyone think it could be?