Strongest gear 1:1

[AndyG]

We all got a ear bashing from the Workshop Manager about getting into 5th too soon and lugging. Basically he was saying our road conditions limit us to 80 km, 4th gear is a direct gear, so stay in 4th while you can.

A quick search shows Puma gearbox, 5th is 1:1 and presumably the strongest, ( no reduction gearing). So should use 5th where possible, esp on load.

Goes without saying that depending on revs, 4th and 6 would be used as needed.

Is this a reasonable premise?

[Toxic_Avenger]

Also interested to know where optimal efficiency lies with the puma.
I've found that 5th is a good 'all rounder' in the 80km/h-100km/h speed.
I usually juggle between 3rd and 4th at slower speeds.
I try to keep RPM at around 2200, as the 2.2L engine is making 80% of available torque at this point. It sort of lugs around anything below 1500. (I've alwaysw dirven petrol engines, not sure if the diesel loves being abused at low RPM?).

Can't offer any advice re strength, other than saying that diff gearing should also be accounted for? Gears IMO are there to be used, so pick one that works for the conditions!

[TeamFA]

We all got a ear bashing from the Workshop Manager about getting into 5th too soon and lugging. Basically he was saying our road conditions limit us to 80 km, 4th gear is a direct gear, so stay in 4th while you can.

This sounds like it refers to the R380 gearbox, where 4th is the 1:1, and 5th gear rides on a much narrower (weaker) section of the layshaft.

I don't know anything about the Puma gearboxes...

[AndyG]

To clarify he was speaking in the context of L.C, but he was saying the 1:1 gear, i.e the main shaft, will always be stronger than those going through reduction gears, or secondary shafts, so use it to the max

[JDNSW]

To clarify he was speaking in the context of L.C, but he was saying the 1:1 gear, i.e the main shaft, will always be stronger than those going through reduction gears, or secondary shafts, so use it to the max

Yes, a straight through geat will always be stronger than any indirect gears. Depending on the gearbox, the difference may not be enough to worry about though. Many gearboxes, including the R380, have an overdrive top gear that is significantly weaker than other gears, because it is assumed that it will never be used when full throttle is required.

Note also that the direct straight through gear will always be more efficient (less fuel wasted in the gearbox and less heart generated) than any indirect gear.

John