I guess these 6 speeds aren't indestructable after all. Coming to Pa. from Iowa last thursday all was going well, 6th gear, cruise set on 75mph, PMCR on 3/3, & EZ on 3, at just over 26,000 GCW. Came into Pa. on I-80, rolling through the hills, suddenly starting up one the fuel started to come one & so did an awful sound. Thought I was hearing things at first, but it got worse. Dropped back to 5th, & all seemed well, back to 6 & no good. After 25 mi. in 5th we pulled in a rest area to have a look, started comming down through the gears, and 4th was bad also. By now I was wishing I'd have let it ride in 5th, with only 160 miles or so to go, but I had already commited to the exit ramp. Sounded rough at an idle with the clutch out, but all looked dry. Rather than pay someone to tow us in, we decided to try to get back out and in 5th. I wouldn't have bet on it, but we got through 1st - 4th, all 4 sounding BAD, but still 5th was good. At 66k plus, I started digging for the warranty book, and the news was good, we're just under the 7/70 with $100 deductable. Went to the dealer today to have a look in the PTO cover & what a mess. Of course the NV5600 is on backorder, but at least I'll get my Luk Ceramataullic in without paying labor.