Low range question "2-LO OK?"

[Curious Hound]

I have a simple question. I swapped out my auto hubs for manual ones this weekend. That went well.

Is it ok to run the transfer case in 4 low with the hubs unlocked? I have "heard" some say it is not. But nobody will tell me why. Maybe that rule comes from other vehicles with quirks.

I like the slow speed control of low range when driving around my family's property, but rarely actually need 4WD. If the hubs are unlocked, I don't have to shift out of 4WD when I drive on the paved driveway.

 

[Curious Hound]

Oh, I guess I should have stated -

3.0L
M50D 5 speed manual
1354 electric transfer case

 

[jeremysdad]

I do it with no problems.

Useful for maneuvering trailers and getting into tight spots.

 

[85_Ranger4x4]

It won't hurt a thing.

 

[AllanD]

Long before I converted my truck to 4x4 I swapped in a 4x4 trans and transfer case to have 2Lo for maneuvering my trailer into it's parking spot....

Later on when my brother left my hood open (retrieving a tool) and my partially installed
"new" engine got rained on and into and subsequently seized and I had to pull it again I decided I had time to remove the cross-member and hang a front axle in the truck.

That all took a single weekend I spent the next month doing the wiring necessary
to switch from a 2.9 to a 4.0 (and incidentally wire in Cruise control, the wiring for my Aux gas tank and a new Stereo)

AD

 

[jeremysdad]

In addition, it's probably good for the system to distribute lube around, especially if you don't 4 wheel much.

 

[Curious Hound]

Thanks. I couldn't think of any logical reason that it would be a problem. Just wanted to check with others.

 

[gw33gp]

Many years ago when I had a 73 FJ55 Landcruiser, the Owner's manual stated that you should occasionally put the transfer case in 4WD and drive it to help keep everything in the front differential properly lubed. It said nothing about having to lock the hubs when doing this. I also used 4WD low without locking the hubs if I needed to go very slow for some reason, like backing a trailer.

 

[85_Ranger4x4]

My D35 has a dead spot in the front driveshaft from where it sat for who knows how long, it is like a detent where it wants to be.

Probably just as well they didn't try it after awhile because the left axle cross was locked up...

 

[Curious Hound]

My D35 has a dead spot in the front driveshaft from where it sat for who knows how long, it is like a detent where it wants to be.

Probably just as well they didn't try it after awhile because the left axle cross was locked up...

Not quite sure what you mean by "dead spot". Interesting idea. Prior to my purchase recently, this truck probably didn't run more than about 200 miles in the past 10 years and there's no telling how long since the previous owner used 4wd , if ever. Considering that, I am finding the vehicle to be in very good condition.

 

[85_Ranger4x4]

As you swing the driveshaft stub from one extreme to the other roughly in the center is a detent where it wants to stay. Once you get through that it swings easy again. Like it has spent a lot of time sitting on one spot without being ran.

BTW this axle was not kept up very well either, lots of neglect.

 

[don4331]

logical reason:

3.0 - 185ft lb torque
1st gear on M5ODR-1 3.72:1
= 690ft lb torque @ pinion.

Ford 7.5" is rated @ 900 ft lb - no issue. (8.8" even less)

3.0 - 185ft lb torque
1st gear on M5ODR-1 3.72:1
low range BW1354 2.48:1
= 1,705ft lb torque @ pinion.

That's more than a Dana 60 is rated for (Dana 60 rated for 1,500)

So, if you stand on skinny pedal in 2-lo, things WILL break (hopefully just tire breaks loose aka spins).

Therefore, OEMs recommend against it.

But, if all you are doing is puttering around the yard/hooking up to trailer/etc, there's no issue.

 

[AllanD]

As for "Distributing lube" the 13-50 & 13-54 Transfer-cases have an internal oil pump that is driven off the output shaft, and there is no way to stop the Planetary from spinning if the transmission input shaft is turning getting the front diff spinning is easily accomplished by locking your hubs for the commute to work one way one day a week...

But then again I'm one of those guys who locks my hubs in mid-October and tends to Leave them locked until April... (I will unlock if I'm getting on the interstate)

AllanD

 

[jeremysdad]

I live in an area where we might get 1 winter event a season...big might...and so the manual shifter I see everytime I drive gets noticed more. Hubs tend to be out sight/mind. Lol.

Good points, though.

 

[Curious Hound]

3.0 - 185ft lb torque
1st gear on M5ODR-1 3.72:1
= 690ft lb torque @ pinion.

Ford 7.5" is rated @ 900 ft lb - no issue. (8.8" even less)

3.0 - 185ft lb torque
1st gear on M5ODR-1 3.72:1
low range BW1354 2.48:1
= 1,705ft lb torque @ pinion.

That's more than a Dana 60 is rated for (Dana 60 rated for 1,500)

So, if you stand on skinny pedal in 2-lo, things WILL break (hopefully just tire breaks loose aka spins).

That bit about standing on the skinny pedal is the key here. Just because 1705 ft-lb of torque is AVAILABLE doesn't mean it's being applied.

I have 150ft-lbs available to apply to a torque wrench. But if I apply my torque to the wrench slowly and smoothly and overcome the inertia in the load at only 20 ft-lbs, The other 130ft-lbs is a moot point. It isn't applied. If I JERK on the wrench to try to move the load quickly, a lot more of the available torque is used and things are more likely to break.

My driving style is more sedate in these situations. Now, back when I had that '06 Mustang GT however....

Well, let's just say more of the AVAILABLE torque was used than what was necessary to merely get the car moving.