The 6 speeds hold up better. The 2nd gen trucks that had a 5 speed were the NV4500 trans and they tend to lose 5th gear a lot. -Chuck
the 5 speeds have a weak 5th gear (lost mine) and they have a lower torque limit plus they seem to have too big of a gap between 2nd and 3rd. I'm getting stuck on some hills at redline in 2nd and 3rd won't pull it.
This is what commonly happens to the 5th gears in NV4500 5-speed transmissions: http://www.quad4x4.com/NV4500 5th Gear Failures and Solutions.htm -Chuck
