I was recently having trouble with my new TKO600. I tried to get answers/info from Tremmec, the vendor I purchassed the transmission from and a few other sources. I couldn't quite get the info I needed. Out of the blue I get a phone call from Bruce Couture at Modern Driveline. I didn't know who was calling or how he knew of my problem. He asked about the symptoms and explained some possible faults and how to address them.
This was an unsolicited call, he knew I was having a problem and called from Idaho to BC Canada just to offer some help and expecting nothing in return.
They do mostly Ford conversions but will set one up for any make. I've never met him or had any business dealings with him but I thought his service did make a difference and want to pass it on.
Yes, input shaft endplay is shimmed under the bearing retainer and the gearlash is shimmed on the output shaft. If the gear mesh/lash is too loose it will clatter, sounds worse with any lopey cam. The pos and neg acceleration of the crank every revolution makes the gearbox sound like it has marbles in it. Increasing the rpm out of idle, say 1500 rpm, smooths out the engine and the noise goes away. The light GM syncromesh oil doesn't quieten the gears as much as the 80/90 oil in a Muncie.