by Gipsy on Tue, 30 May 2023 6:40 +0000
Driving at the higher revs is easier on most of the driveline because the momentum of the components flattens the curve when extra loads are expected. The engine in particular is damaged by lugging at low revs with a high load. The engine power/torque curve is suited to a specific rev range (around 2000 to 3500rpm) so it's always best to use this range. Particularly diesels hate grunting at high loads/low revs, despite the torque levels at anything over 1000rpm. Just don't lug your engine, it hurts everything especially fuel consumption/wastage.
Edit: if I read your question correctly though, I guess you are specifically asking about the final gearing; rear axle/diff etc. As noted previously, the physics of torque in torque out, the load on those components are basically not affected by the gear selection but they are affected by shock loads at low speed because as you throttle up to overcome a load, slow moving components can suffer shock loads as the power increases to overcome the load no matter which gear you are in. There is a problem with shear loads at very slow speeds as the torque from the engine can provide a shock load to those components as the gearing is magnifying (multiplying) the torque from the engine. Thus as your question asks specifically, no the shear load is not really variable at 100kph no matter which gear you select because the power required to maintain that speed is relatively constant irrespective of which gear selection. You will however use more/less fuel and affect engine wear depending on which gear you are using.
Cheers Gipsy
although I'm sure somebody will challenge that
even Einstein wasn't certain of his theories.
My 2013 auto D4D DC SR5, prefilter, 3" exhaust and Chip with egt probe, stock SR5 rims with Toyo Open Country AT2 265/65R/17's