4hi and 4lo
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Joined: Nov 2007
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RE: 4hi and 4lo
Basically 2 Hi, 4 Hi and 4 Lo are "gears" for your transfer case (like 1-6 plus reverse for a manual).
The transfer case sits behind the transmission and is connected by driveshafts to the rear and front axles.
In 2 Hi it sends 100% of engine power to the rear axle and the driveshaft to the front axle just free wheels. The gear ratio here is 1 to 1 so no additional gear reduction beyond that supplied by the transmission happens.
In 4 Hi the front driveshaft is engaged and 50% of engine power is sent to each axle. The gear ratiohere is again 1 to 1.
In 4 Lo the power is split 50% just like in 4 Hi but there's a lower gear ratio (2.72 to 1 in the New Process 241 case in my 2003) to give extra grunt on top of that supplied by the transmission.
Keep in mind the transfer case has no differential action allowing one axle to turn faster than the other (which must happen when turning) so it will tend to bind up when used on high traction surfaces like dry pavement. This isn't an issue on dirt, mud, rocks or snow where wheel slip can provide the differential action.
The transfer case sits behind the transmission and is connected by driveshafts to the rear and front axles.
In 2 Hi it sends 100% of engine power to the rear axle and the driveshaft to the front axle just free wheels. The gear ratio here is 1 to 1 so no additional gear reduction beyond that supplied by the transmission happens.
In 4 Hi the front driveshaft is engaged and 50% of engine power is sent to each axle. The gear ratiohere is again 1 to 1.
In 4 Lo the power is split 50% just like in 4 Hi but there's a lower gear ratio (2.72 to 1 in the New Process 241 case in my 2003) to give extra grunt on top of that supplied by the transmission.
Keep in mind the transfer case has no differential action allowing one axle to turn faster than the other (which must happen when turning) so it will tend to bind up when used on high traction surfaces like dry pavement. This isn't an issue on dirt, mud, rocks or snow where wheel slip can provide the differential action.
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Joined: Nov 2007
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RE: 4hi and 4lo
ORIGINAL: sddunn2
Great explaination scottj175 u the man !![sm=hail.gif]
Great explaination scottj175 u the man !![sm=hail.gif]
I've been a software developer for 10 years but also have 5 years behind the parts counter in my past so I'm used to having to explain technical stuff.
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Joined: Nov 2007
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From:
RE: 4hi and 4lo
ORIGINAL: ScottJ175
Basically 2 Hi, 4 Hi and 4 Lo are "gears" for your transfer case (like 1-6 plus reverse for a manual).
The transfer case sits behind the transmission and is connected by driveshafts to the rear and front axles.
In 2 Hi it sends 100% of engine power to the rear axle and the driveshaft to the front axle just free wheels. The gear ratio here is 1 to 1 so no additional gear reduction beyond that supplied by the transmission happens.
In 4 Hi the front driveshaft is engaged and 50% of engine power is sent to each axle. The gear ratiohere is again 1 to 1.
In 4 Lo the power is split 50% just like in 4 Hi but there's a lower gear ratio (2.72 to 1 in the New Process 241 case in my 2003) to give extra grunt on top of that supplied by the transmission.
Keep in mind the transfer case has no differential action allowing one axle to turn faster than the other (which must happen when turning) so it will tend to bind up when used on high traction surfaces like dry pavement. This isn't an issue on dirt, mud, rocks or snow where wheel slip can provide the differential action.
Basically 2 Hi, 4 Hi and 4 Lo are "gears" for your transfer case (like 1-6 plus reverse for a manual).
The transfer case sits behind the transmission and is connected by driveshafts to the rear and front axles.
In 2 Hi it sends 100% of engine power to the rear axle and the driveshaft to the front axle just free wheels. The gear ratio here is 1 to 1 so no additional gear reduction beyond that supplied by the transmission happens.
In 4 Hi the front driveshaft is engaged and 50% of engine power is sent to each axle. The gear ratiohere is again 1 to 1.
In 4 Lo the power is split 50% just like in 4 Hi but there's a lower gear ratio (2.72 to 1 in the New Process 241 case in my 2003) to give extra grunt on top of that supplied by the transmission.
Keep in mind the transfer case has no differential action allowing one axle to turn faster than the other (which must happen when turning) so it will tend to bind up when used on high traction surfaces like dry pavement. This isn't an issue on dirt, mud, rocks or snow where wheel slip can provide the differential action.
