100 series turbo diesel tachometer reading

Sounds about right , but if we wanted to get pedantic we would need use a GPS for actual speed over ground as Toyotas have been notorious for the speedo to read 4% higher than actual speed . IE: speedo showing 100 when in fact vehicle doing 96 ... ODO time vs distance varies the opposite ........

Not necessarily, I think.

The auto can rev lower because of the torque multiplication in the torque converter. At least, that's how I understand it.

I had a Kia Sorrento manual. Its revs in top gear at 100kph were considerably higher than a workmate's auto version.

Maybe a stretch, but I presume the same logic would apply, regardless of brand.

I too think the manual will rev more than the Auto, cannot compare them. The speed reading is an indicated on the dash not actual. The speedo on both may vary as well. Best to verify the rpm when using a good GPS. It should be the same as the 5th ratio overdrive amount multiplied with the final drive ratio, (which may well be different between auto and manuals) and the distance per rev of the tyres. Or use radius of, axle to ground etc. The calculated ratio of 5th and final drive with actual distance per rev is the most accurate AND it verifies the rev counter as well.

Could also be tyre size as well.

The reason for the different engine revs between manual and auto 100 series, is because they have different diff ratios.

100 series Auto - 3.9:1 ratio

100 series Manual - 4.3:1 ratio

The torque converter in an auto effectively locks up at highway speeds, making the auto drivetrain equivalent to a manual drivetrain at those speeds.

Cheers, Ron.

As Ron has pointed out, diff ratios are different, also I would hazard a guess that the final drive ratios in top gear would also be different.

Macca.