What do your failures have in common (if anything)? And what failed?
How much power are you running and were you wheeling or just driving when they failed?
And did you get back home, or were the failures too much and left you stranded?
Very curious.
Thanks
Paul
I was running an NV4500 (and had my own issues over the years), but the three ZF failures I've been privy to were all on full size truck applications. Lots of miles combined with heavy trailers and steep hills is hard on anything...2 of the 3 ZF's chewed up the synchros (especially 2/3), possibly fouled the oil and then started working on the bearings. Both were more or less still driveable, but not fun to drive. They weren't over-maintained by any stretch of the imagination, but the oil actually looked better than I expected when they came apart given how noisy and hard to shift they were. The other one couldn't seem to keep a set of input bearings in it...never did figure out why after three new inputs, new bearings, endplay checks, etc. I've heard things about the dual-mass flywheels used on some applications as potentially causing problems, so if that was the case, then that wouldn't have been the transmission's fault.
For 3 that failed though, I've seen many more perform admirably. I went NV4500 at the time, because the internet wasn't what it is today and I'd heard it was more robust than the ZF, which was my concern at the time. After going through the 5th-gear issue on the NV4500 and then dealing with some rattles due to the blocking rings, I would probably run a ZF now instead of the NV. Cheaper and better core/parts availability due to higher numbers of units, not to mention not needing adapters.