Locking/Unlocking the Centre Diff while moving

[Jonny72]

With snow forecast to arrive in Rutland tomorrow, I’d like to know whether I can lock the Centre Differential while driving should conditions dictate e.g. if the road becomes covered with snow, and unlock the diff when the road is clear? I’ve locked and unlocked the centre differential several times, but have always been stationary at the time…. Perhaps a silly question, but thought I’d ask here rather than risk crunching noises…

 

[HereinDaRockies]

Yes you can

 

[ECrider]

I am normally rolling when locking or unlocking diff. I have not done it at speeds in excess of 15mph and would not feel comfortable doing so. I think if front and rear axle are turning at the same speed then there should be no adverse effects. If in doubt slow it down.

 

[Tazzieman]

Yes.

 

[landmannnn]

As above, as long as the wheels aren't spinning or you are not corning it will be fine. I've regularly switched it at 40mph.

Actually you don't really need to engage the centre diff unless you are climbing one of Rutland's notorious mountains. I believe some of them are as high as 200ft.

 

[AztecGrenadier]

I was worried about engaging the center diff lock. It was stiff and not very natural.

I just kept practicing and now I can lock and unlock at will. Very satisfying. It also gives you an idea of what the warning lights will do.

Access to my house is via a steep dirt road that we pay part of the maintenence fee.

It had some clay on the surface.

I have gotten in the habit of engaging the center lock whenever we have heavy rain or snow.

I think it helps reduce dashboard.

Practice...

I also practiced switch to low and locking the rear and front diffs. No worries about lights or noises anymore.

 

[Skymark]

On a related note, during my routine maintenance service visit I struck up a casual conversation with my rep about the fact the transfer case sometimes does not fully engage, pops out and grinds. He asserted strongly that the proper way to shift the transfer case into low is to do so while rolling forward at 1-2 Mph. This is directly counter to the owners manual which is full stop in neutral. Now on trail, sometimes the gears are not well-aligned and by-feel I know I need to inch forward and then try again. But I don't see how shifting on the slow-fly is a better approach. In any event, I don't intend to stray from the official guidance while still under warranty but a good fireside-chat-over-beers topic.

 

[AaronS]

On a related note, during my routine maintenance service visit I struck up a casual conversation with my rep about the fact the transfer case sometimes does not fully engage, pops out and grinds. He asserted strongly that the proper way to shift the transfer case into low is to do so while rolling forward at 1-2 Mph. This is directly counter to the owners manual which is full stop in neutral. Now on trail, sometimes the gears are not well-aligned and by-feel I know I need to inch forward and then try again. But I don't see how shifting on the slow-fly is a better approach. In any event, I don't intend to stray from the official guidance while still under warranty but a good fireside-chat-over-beers topic.

I found that rolling at a slow walking pace helps moving between low/high the first few times. After that doesn't matter... though I tend to stop on a slight incline just in case I need the truck to roll a few feet to fully engage the t-case.

T-case lock/unlock... as mentioned, just make sure all wheels are rotating at the same speed.

 

[CrazyOldMan]

With snow forecast to arrive in Rutland tomorrow, I’d like to know whether I can lock the Centre Differential while driving should conditions dictate e.g. if the road becomes covered with snow, and unlock the diff when the road is clear? I’ve locked and unlocked the centre differential several times, but have always been stationary at the time…. Perhaps a silly question, but thought I’d ask here rather than risk crunching noises…

Driving on snow covered roads? Since I live where it’s winter 11 months out of the year (so my wife says) and drive on snow and ice covered roads a lot - the unlocked 4WD is almost always sufficient for me - but I have dedicated wheels and snow tires for winter. I just rarely need to lock if I’m not offroad or being a doofus in snowbanks. It’s just so capable on winter roads, especially with the right tires.

 

[Blackwolf]

Those of us as old as the hills will remember that when Land-Rover introduced the LT230 transfer case with full-time four-wheel drive and centre diff lock to replace the earlier selectable 2/4WD transfer box, their advice was that the CDL should be locked whenever you would have pressed the yellow knob to select 4WD on the earlier box.

In practice when driving one of my Series I Land-Rovers I will press the yellow knob if driving in snow as soon as there is a tendency for a back wheel to spin. With my Defender I engage the CDL as soon as there is a tendency for any one or more wheel to spin, and I will do the same with the Grenadier. In both cases there will be no transmission windup since there is enough slipperiness to allow the required scrub.

If anyone reading this has no idea what I am talking about when I mention the 'yellow knob', history books are available !

 

[DenisM]

Driving on snow covered roads? Since I live where it’s winter 11 months out of the year (so my wife says) and drive on snow and ice covered roads a lot - the unlocked 4WD is almost always sufficient for me - but I have dedicated wheels and snow tires for winter. I just rarely need to lock if I’m not offroad or being a doofus in snowbanks. It’s just so capable on winter roads, especially with the right tires.

My youngest brother spent 15 yrs living in upper NY state about an hour's drive south from Montreal. He returned to the land of Oz. about 8 yrs ago. He told me that where he lived in the USA there were two seasons: July and "winter"! His preferred mode of travel through snow and over icy roads was the humble Honda Civic (he owned several over the years) shod with appropriate tyres.

 

[Happyoldgit]

Those of us as old as the hills will remember that when Land-Rover introduced the LT230 transfer case with full-time four-wheel drive and centre diff lock to replace the earlier selectable 2/4WD transfer box, their advice was that the CDL should be locked whenever you would have pressed the yellow knob to select 4WD on the earlier box.

In practice when driving one of my Series I Land-Rovers I will press the yellow knob if driving in snow as soon as there is a tendency for a back wheel to spin. With my Defender I engage the CDL as soon as there is a tendency for any one or more wheel to spin, and I will do the same with the Grenadier. In both cases there will be no transmission windup since there is enough slipperiness to allow the required scrub.

If anyone reading this has no idea what I am talking about when I mention the 'yellow knob', history books are available !

Makes perfect sense to me and im a walking antique too. Over the decades I’ve pushed a yellow knob and pulled and pushed a red one in a Series more times than I can remember. Same applies to the vacuum operated switch in a RRC and pulled and pushed in various 90’s, 110’s, 127/130’s and Defenders.

 

[landmannnn]

I never understood why the pickup manufacturers went to a rotary dial involving multiple stepper motors and at least 3 position sensors.
Surely much more expensive than a simple lever and rod linkage. And without doubt less reliable.

 

[CrazyOldMan]

My youngest brother spent 15 yrs living in upper NY state about an hour's drive south from Montreal. He returned to the land of Oz. about 8 yrs ago. He told me that where he lived in the USA there were two seasons: July and "winter"! His preferred mode of travel through snow and over icy roads was the humble Honda Civic (he owned several over the years) shod with appropriate tyres.

Yeah - those guys know snow. Amazing what the right tires can do. On a Civic, he was basically bobsledding down the road. That’s awesome. And for an Aussie to pull that stunt . . .

 

[skinny_tom]

Makes perfect sense to me and im a walking antique too. Over the decades I’ve pushed a yellow knob and pulled and pushed a red one in a Series more times than I can remember. Same applies to the vacuum operated switch in a RRC and pulled and pushed in various 90’s, 110’s, 127/130’s and Defenders.

And we've been saved from the second black knob on our new rides by modern transmissions with additional gears. The overdrive was a lifesaver on my IIa trying to cover the expanse of southern California for the worthwhile trips.

 

[255/85]

My youngest brother spent 15 yrs living in upper NY state about an hour's drive south from Montreal. He returned to the land of Oz. about 8 yrs ago. He told me that where he lived in the USA there were two seasons: July and "winter"! His preferred mode of travel through snow and over icy roads was the humble Honda Civic (he owned several over the years) shod with appropriate tyres.

Front wheel drive and some studded tires or light cable chains will best most suburban winter roadways. The Mrs. drove an '89 Civic for years and loved it... until she discovered it was a launch ramp for SUVs in head on collisions.

 

[255/85]

And we've been saved from the second black knob on our new rides by modern transmissions with additional gears. The overdrive was a lifesaver on my IIa trying to cover the expanse of southern California for the worthwhile trips.

Maybe you're talking about a Fairey overdrive? Had one in a Land Cruiser. Some of the best money I ever invested in that rig. Wish they were still made as I could use one in my 40 series. I spoke to the guy that had the rights to them a couple of decades ago in hopes I could get him to make a run. It was like talking to a blank wall unless I said ''Land Rover''. Then he wouldn't shut up.

 

[Jonny72]

Driving on snow covered roads? Since I live where it’s winter 11 months out of the year (so my wife says) and drive on snow and ice covered roads a lot - the unlocked 4WD is almost always sufficient for me - but I have dedicated wheels and snow tires for winter. I just rarely need to lock if I’m not offroad or being a doofus in snowbanks. It’s just so capable on winter roads, especially with the right tires.

Great advice, thank you. I‘M running the BFG KO2s, so assume they’ll be good enough in the conditions expected…

 

[Jonny72]

Those of us as old as the hills will remember that when Land-Rover introduced the LT230 transfer case with full-time four-wheel drive and centre diff lock to replace the earlier selectable 2/4WD transfer box, their advice was that the CDL should be locked whenever you would have pressed the yellow knob to select 4WD on the earlier box.

In practice when driving one of my Series I Land-Rovers I will press the yellow knob if driving in snow as soon as there is a tendency for a back wheel to spin. With my Defender I engage the CDL as soon as there is a tendency for any one or more wheel to spin, and I will do the same with the Grenadier. In both cases there will be no transmission windup since there is enough slipperiness to allow the required scrub.

If anyone reading this has no idea what I am talking about when I mention the 'yellow knob', history books are available !

I still have a 109” Series III. Good advice, thank you

 

[CrazyOldMan]

Great advice, thank you. I‘M running the BFG KO2s, so assume they’ll be good enough in the conditions expected…

They are garbage on icy roads. Yes they are 3PMS rated - but I think if you do a lot of snow and ice, real snow tires are the way to go (I’m not even talking about studded tires). I switch over in November once the temperature drops. But for infrequent snow days - probably fine for an AT tire. I hear the K03’s are a little better.