I've experienced it before, when I swapped an SR. It would only smooth out at 80+ in 5th gear. The tranny fuild was changed (put in synth originally, synchros didn't like it), and it doesn't rumble until 2k rpms now. Maybe I put too much fluid in before, i dunno. Two and a half quarts at Jiffy Lube fixed it right up.

For argument's sake in this case, we'll just say that the KA and SR trannies are similar enough!

Chris