Nissan Patrol 4x4 (Africa)

Clem wrote:NMAD, you referring to the 4.8?

In any event, that's exactly my issue.

Clem wrote:Noel, I'm totally confused. My vehicle (2013 4.8) has a 5 speed transmission and there's certainly no overdrive selector switch. (?)

NMAD wrote:I am not a mechanic but I see it like this: the auto box has a torque converter and this locks when you are in top gear ie 5th and it almost acts like an extra gear as its lowers the revs more, so if you are cruising at 120km hour in 5th gear at say 2400 rpm and then the transmission locks up the revs will drop lower to say 2200 rpm and you will still go the same speed: it saves fuel but not sure how much.


https://en.wikipedia.org/wiki/Torque_co ... converters

Lock-up torque converters[edit]
As described above, impelling losses within the torque converter reduce efficiency and generate waste heat. In modern automotive applications, this problem is commonly avoided by use of a lock-up clutch that physically links the impeller and turbine, effectively changing the converter into a purely mechanical coupling. The result is no slippage, and virtually no power loss.

The first automotive application of the lock-up principle was Packard's Ultramatic transmission, introduced in 1949, which locked up the converter at cruising speeds, unlocking when the throttle was floored for quick acceleration or as the vehicle slowed down. This feature was also present in some Borg-Warner transmissions produced during the 1950s. It fell out of favor in subsequent years due to its extra complexity and cost. In the late 1970s lock-up clutches started to reappear in response to demands for improved fuel economy, and are now nearly universal in automotive applications.