Author Topic: Gen 2 4wd operation question  (Read 149 times)

SammyS

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Gen 2 4wd operation question
« on: March 22, 2019, 08:21:40 PM »
Hi all- new to the world of 4wd here and I have a question-  when shifting from 2wd to 4wd I thought the selection was in the transfer case, but then what does the actuator at the front differential do?  1992 SR stock.  My vehicle has the rear locker, but the front diff never locks right?

Shovel

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Re: Gen 2 4wd operation question
« Reply #1 on: March 22, 2019, 09:41:28 PM »
There are two different things going on - you're using the transfer case lever to directly engage the chain & front output shaft of the transfer case and at the same time the front axle disconnect is being told to connect the front wheels to the front driveshaft.

The reason for that is if you only did one or the other, the front driveshaft and the bottom half of the transfer case would be spinning all the time you're moving.     That's a lot of wear, a lot of fuel, a lot of noise and vibration.   

On light duty AWD vehicles it's less of a big deal because they are transmitting a fraction of the torque you can in low range into big tires, and they're usually doing it with (numerically) lower final drive ratios so the size and weight and rotating speed of all the parts we're talking about here are WAY lower and can be done with little CV joints and 7/8" diameter driveshafts and stuff.    That's why something like a Subaru can be in full engagement all the time and your Montero can't (or.. shouldn't) .   

The front diff is not a locking differential, no USDM Montero had a locking or limited slip front diff from the factory.     There are a few choices for changing that if you like spending time and money. 


SammyS

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Re: Gen 2 4wd operation question
« Reply #2 on: March 23, 2019, 10:54:56 PM »
Thank you Shovel!