Transfer case in low, rear wheels only

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TXFinder
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Joined: Thu Oct 18, 2012 12:16 pm
Location: Central TX

Transfer case in low, rear wheels only

Postby TXFinder » Tue Oct 10, 2017 7:18 pm

Does anyone know if there is a way to disconnect the front differential so the hubs do not engage when the transfer case is in the 4LO position? That would leave only the rear diff in low gearing mode, which is what I want. I need to pull a heavy boat up a steep long ramp and don't want the front and rear to bind the transfer case. I haven't looked under there but I'm thinking there is a [electrical] connection going to the front I could disconnect. Thoughts?


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smj999smj
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Postby smj999smj » Wed Oct 11, 2017 3:27 pm

I don't think you can do it electrically, especially with the manual transfer case. If you had the AUTO mode transfer case of the LE models, I would think "maybe," but I would be doubtful. The front driveshaft is always turning with the front wheels, so the 4WD activation is accomplished inside the transfer case; there is no actuator on the front axle like there is on old Jeeps.

docwatson
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Postby docwatson » Wed Oct 11, 2017 8:20 pm

Remove the front driveshaft?

Everything inside the transfer case is mechanical so I would think the only way to accomplish a RWD Low would be to remove the front driveshaft.

TXFinder
Posts: 17
Joined: Thu Oct 18, 2012 12:16 pm
Location: Central TX

Postby TXFinder » Thu Oct 12, 2017 6:46 am

Thanks smj. I was mistakenly thinking that the 4wd activation was at the hubs.

Doc, I thought of that and will do that IF the yokes on both the front diff and front of transfer case are 'bolt on', versus slip on. I just haven't looked specifically at that in all my times under there thru the years. I will check.

TXFinder
Posts: 17
Joined: Thu Oct 18, 2012 12:16 pm
Location: Central TX

Postby TXFinder » Thu Oct 12, 2017 7:21 am

Just looked at the service manual and it appears both differential and transfer case yokes (they call them 'companion flange') are secured with a lock nut. So, I will remove front driveshaft.

Thanks guys.

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labsy
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Postby labsy » Mon Nov 06, 2017 6:24 pm

As long as you go uphill in 4LO only in STRAIGHT line, there is (theoretically) no additional stress to driveline, because all 4 wheels turn just about the same. This is especially (and practically) true in non-paved roads.

So if that's your situation, you can safely shift into 4LO and pull that rig in straight line uphill and nothing bad should happen.
Even more - in 4LO torque is evenly distributed 50/50 between front and rear diff, and so is also stress on driveshafts and particularly on U-joints. Which is even better than just rear drive.

On contrary, if that uphill is PAVED AND CURVED, I do not recommend driving in 4LO. Because steering left/right in 4LO presents a lot of stress to gears and shafts due to wheel speed difference in curve.

TXFinder
Posts: 17
Joined: Thu Oct 18, 2012 12:16 pm
Location: Central TX

Postby TXFinder » Mon Nov 06, 2017 7:24 pm

labsy wrote:As long as you go uphill in 4LO only in STRAIGHT line, there is (theoretically) no additional stress to driveline, because all 4 wheels turn just about the same. This is especially (and practically) true in non-paved roads.

So if that's your situation, you can safely shift into 4LO and pull that rig in straight line uphill and nothing bad should happen.
Even more - in 4LO torque is evenly distributed 50/50 between front and rear diff, and so is also stress on driveshafts and particularly on U-joints. Which is even better than just rear drive.

On contrary, if that uphill is PAVED AND CURVED, I do not recommend driving in 4LO. Because steering left/right in 4LO presents a lot of stress to gears and shafts due to wheel speed difference in curve.
I totally agree. Your last paragraph is exactly why I needed to disengage the front. Coarse concrete (super grip), steep, and a curve at the top. I can't imagine the stress it would have put on the transfer case. I removed the front driveshaft, rear wheel only in LO, and all worked out great.


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