HOWTO : River crossings, and tough off road terrain in non 4x4 vehicles

[anupmathur]

.... unless and until the airbreather is of the highest quality with some technology made specially for amphibious vehicles.(I am sure someone would have designed an air breather for amphibious vehicles too,not done the research yet lazy chap here)

And indeed such vents are not uncommon at all. It is simply a non-return valve (often a ball type) that allows mist/vapour from the gear box to escape but does not allow any liquids from outside to enter.

Water can enter gearbox due to a number of reasons. ....

I'm trying to figure out what these number of reasons could be. Can't think of any....

 

[TIMAP]

Thanks Anup Sir,
Recently one of my team mates used this non-return valve type breather in one of the gearboxes he designed. But I am not so sure about how much water wading depth it can sustain. Thanks for your confirmation.

 

[anupmathur]

.... But I am not so sure about how much water wading depth it can sustain. .....

That would be the least of your worries. As long as the NR valve itself is made well it will easily bear a few bars pressure, which is far larger than anything required for fording water. You're looking for a couple of hundred mm water gauge!

 

[tsk1979]

I'm trying to figure out what these number of reasons could be. Can't think of any....

Faulty seals. Faulty breather. If you are doing deep water fording, these are the two simple cases where you may have water entering the gearbox.
If you are not doing deep water fording, it can be due to "transmission cooler malfunction". That said, I am not sure whether manual transmission vehicles have a water cooled transmission.

 

[TIMAP]

^^^ I dont think manual transmissions have water cooled transmissions. Even automatic transmissions not all are cooled by water. Sometimes they just put a heatexchanger which exchanges heat with air and not with water.

@Anup Sir,
Recently I had a look at the One-way valve design of a breather and certainly it was not a ball type of valve which we will normally consider it to be. Because I think lifting a spring loaded steel ball would require lot of pressure build up. Anyway these breathers get clogged if you were to drive it through a dirty nallah and would certainly require attention after the trip. Otherwise a clogged breather would cause Oil seals to leak.

 

[AnupamR]

Good information Tanveer... thanks for sharing... The headlight part was really helpful...