Transfer Box Lever

DaveB · Mar 29, 2023

bigleonski said:
Dave for me it’s never been a requirement to go from high to low or low to high on the move. In the numerous 4wds I’ve had that’s never been required and always been done static (or almost).

The previous argument has been the capacity to engage the centre diff lock (in high range) whilst driving. Every 4wd I’ve had has this capacity (Toyota up to around 100km/hr), whether via a stick or push button, and not to have that capability would be a major flaw.

Yes I remember you made that clear much earlier.
I could be wrong on part/all of the following as I am not a diff expert
I believe this is possible on a Torsen style centre diff as used in lots of vehicles and in our popular dual cab utes that are 2WD on road and locked 4WD off road. They don't usually have 4WD unlocked so need to be able to be locked on the move.
I was surprised to learn that while it is possible to lock and unlock the centre diff in a Defender old series at any speed LR certainly don't recommend doing it unless you are pointing all wheels straight ahead and none of them are slipping.
I sure wouldn't be prepared to take that chance particularly when they state it will cause damage, not may cause damage.

DaveB · Mar 29, 2023

A side point that I discovered when researching was that early discoveries were all shipped with centre diff lock fitted but if you didn't select and pay for the option they just didn't connect it into the cabin.
So save the money and just connect it later yourself.

View: https://www.youtube.com/watch?v=Da3Ys0xG2PA

cmurray · Mar 30, 2023

DaveB said:
A side point that I discovered when researching was that early discoveries were all shipped with centre diff lock fitted but if you didn't select and pay for the option they just didn't connect it into the cabin.
So save the money and just connect it later yourself.

View: https://www.youtube.com/watch?v=Da3Ys0xG2PA

Actually Dave, there was no option for a centre diff lock on the Discovery 2 from launch. Land Rover were so convinced that their traction and hill descent controls were good enough that they removed the control for it. It was possible to lock the centre diff manually, by using an 11mm spanner on the transfer case, but if the engine was turned on while locked, it would disable the ABS system, which meant that there was no traction control or hill descent control.
For the 2002 model year, they actually removed the mechanism in the transfer case to control the centre diff lock. If you have one of these, you need to replace the front output housing on the transfer case for one that has a centre diff lock.
After much complaining from Australia and South Africa, the centre diff lock control was re-introduced to those two markets from 2003, when the face lifted Discovery 2 was released.

bigleonski · Mar 30, 2023

@DaveB
Yeah I get it.
But the landcruisers have been constant 4wd for decades and centre diff is not locked until you engage the CDL.
I don’t undewhy the constant 4wd IG would be any different, but mechanics aren’t my strong point.

DaveB · Mar 30, 2023

bigleonski said:
@DaveB
Yeah I get it.
But the landcruisers have been constant 4wd for decades and centre diff is not locked until you engage the CDL.
I don’t undewhy the constant 4wd IG would be any different, but mechanics aren’t my strong point.

Toyota uses a Torsen T-3 in the center differential of the 4Runner Limited, FJ Cruiser 6-speed manual, Land Cruiser, Land Cruiser Prado and Lexus GX470, with manual locking feature

Behaviour of Torsen differentials[edit]

The Torsen differential works just like a conventional differential, but can lock up if a torque imbalance occurs, the maximum ratio of torque imbalance being defined by the torque bias ratio (TBR).[2] When a Torsen has a 3:1 TBR, that means that one side of the differential can handle up to 3⁄4 while the other side would have to only handle 1⁄4 of applied torque. During acceleration under asymmetric traction conditions, so long as the higher traction side can handle the higher applied torque, no relative wheelspin will occur. When the traction difference exceeds the TBR, the slower output side of the differential receives the tractive torque of the faster wheel multiplied by the TBR; any extra torque remaining from applied torque contributes to the angular acceleration of the faster output side of the differential.

The TBR should not be confused with the uneven torque-split feature in the planetary-type Torsen III. The planetary gearset allows a Torsen III center differential to distribute torque unevenly between front and rear axles during normal (full traction) operation without inducing wind-up in the drivetrain. This feature is independent of the torque bias ratio.

Obviously it works extremely well but is a lot more complicated than the Grenadier transfer case and diff lock system.

muxmax · Mar 30, 2023

DCPU said:
High to low is difficult to achieve simply because of the gearing; but low to high is reasonable when towing, especially when you've stopped on an uphill and need to start off again.

That’s one thing that confused me when reading the manual. They say on page 87 of the German version that the car has to be standing but on page 86 they list starting off when towing as a use case for low. I would assume that you would want to switch to high, once the train got going. Then again page 87 expressly says „switching from high to low“ needs a stopped vehicle. Maybe that implies that stopping is not necessary when shifting from low to high. Anyway I am surprised that the entire subject, including locking, isn’t really covered in depth.

IG_in_AZ · Mar 30, 2023

muxmax said:
That’s one thing that confused me when reading the manual. They say on page 87 of the German version that the car has to be standing but on page 86 they list starting off when towing as a use case for low. I would assume that you would want to switch to high, once the train got going. Then again page 87 expressly says „switching from high to low“ needs a stopped vehicle. Maybe that implies that stopping is not necessary when shifting from low to high. Anyway I am surprised that the entire subject, including locking, isn’t really covered in depth.

I specifically asked my driving instructor about this at the event I attended yesterday. He gave a low-range towing example of pulling a boat on a trailer up a launch ramp, where you're pulling a heavy load up a hill, for a short duration, and maneuvering in the immediate area before shifting to high range and driving away once everything is strapped down and secure. He said that the transfer case is not synchronized and it was not recommended to go from low to high while moving.

My personal experience with every other 4X4 I've driven, (Ford, Dodge and Chevy pickup trucks and SUVs as well as Jeeps) you should always stop, shift the transmission to neutral, switch the transfer case to low or high gear, then re-engage the transmission. Maybe I was doing it wrong, but that's how I was taught.

Spjnr · Mar 30, 2023

IG_in_AZ said:
I specifically asked my driving instructor about this at the event I attended yesterday. He gave a low-range towing example of pulling a boat on a trailer up a launch ramp, where you're pulling a heavy load up a hill, for a short duration, and maneuvering in the immediate area before shifting to high range and driving away once everything is strapped down and secure. He said that the transfer case is not synchronized and it was not recommended to go from low to high while moving.

My personal experience with every other 4X4 I've driven, (Ford, Dodge and Chevy pickup trucks and SUVs as well as Jeeps) you should always stop, shift the transmission to neutral, switch the transfer case to low or high gear, then re-engage the transmission. Maybe I was doing it wrong, but that's how I was taught.

Another common requirement for towing in L/Unlocked would be manoeuvring a heavy trailer through a tight or precarious spot. Less strain on the transmission, and more control, especially in reverse, as RPMs can be kept far lower

Logsplitter · Mar 30, 2023

Spjnr said:
Another common requirement for towing in L/Unlocked would be manoeuvring a heavy trailer through a tight or precarious spot. Less strain on the transmission, and more control, especially in reverse, as RPMs can be kept far lower

Always do that when reversing with a trailer. Slow and steady, easy to control and easy on the transmission.

Spjnr · Mar 30, 2023

Logsplitter said:
Always do that when reversing with a trailer. Slow and steady, easy to control and easy on the transmission.

Biggest gripe with the V6 Amaroks... no L box and a tall reverse gear. Not the best combo

Hobbes · Mar 30, 2023

bigleonski said:
@DaveB
Yeah I get it.
But the landcruisers have been constant 4wd for decades and centre diff is not locked until you engage the CDL.
I don’t undewhy the constant 4wd IG would be any different, but mechanics aren’t my strong point.

80 series Land Cruisers all have wiring to allow the center diff lock to be manually engaged. At least, all of them in NA. You merely have to buy the switch and plug it in. Works great. I guess in modern times they’d call that an Easter egg.

Also with the 80 series, you can unplug a single wire and low range is selectable in 2 wheel drive for those that have the need.

Logsplitter · Mar 30, 2023

Spjnr said:
Biggest gripe with the V6 Amaroks... no L box and a tall reverse gear. Not the best combo

That’s not good for a commercial vehicle that people tow with. Which is often what those double cab pick ups are used for. Especially on the south coast towing boats I see a lot of VW trucks.

Spjnr · Mar 30, 2023

Logsplitter said:
That’s not good for a commercial vehicle that people tow with. Which is often what those double cab pick ups are used for. Especially on the south coast towing boats I see a lot of VW trucks.

Yeah from what I heard (Aussies chime in) in OZ they caved to consumer demand and put a proper low box in the work spec ones. Shame as they're a great option otherwise here in the UK where we are somewhat starved for good tow motors.... Until now

Logsplitter · Mar 30, 2023

Spjnr said:
Yeah from what I heard (Aussies chime in) in OZ they caved to consumer demand and put a proper low box in the work spec ones. Shame as they're a great option otherwise here in the UK where we are somewhat starved for good tow motors.... Until now

You’re right the Grenadier should be a good tow vehicle. Let’s hope.
ive a mate who tows heavy boats and Mitsubishi L200 head gaskets a major problem as was mine even without towing at the time. He now’s uses a Ford ranger 3.2 but on 2nd engine as he works them hard.

Spjnr · Mar 30, 2023

Logsplitter said:
You’re right the Grenadier should be a good tow vehicle. Let’s hope.
ive a mate who tows heavy boats and Mitsubishi L200 head gaskets a major problem as was mine even without towing at the time. He now’s uses a Ford ranger 3.2 but on 2nd engine as he works them hard.

None of the 4 cylinder pickups are great tow vehicles I've found. mates just bought a 1.9 Dmax and he could hardly break 50mph with 2.5 ton on the back. The Fords seem to go pop a lot, as do the Nissans. The Toyotas are decent but not breath-taking. Once you've towed with a v8 diesel Range Rover, these trucks dont feel the same! Hoping the gearing, Low down torque, weight, solid rear axle and engine displacement of the Grenny make it a top tow car.

Tom D · Mar 30, 2023

I reckon for towing a heavy trailer through town low range might be ok. Not sure what it would do for fuel consumption though. The Grenadier does have the feature of being able to see transmission oil and engine oils temps so at least that can be monitored to see if low range is really necessary. I tow in Edinburgh a lot which is a hilly city, it will be interesting to see how driving around in low box works. If it can do 50mph in 8th gear i doubt I’d get it out of 6th..

A cautionary tale though while travelling round the city bypass in the morning in my defender I was stuck in the usual nose to tail queue for the 5 miles from Sherrifhall to Dreghorn, average speed probably about 10mph. It was the same every day. One day I had the bright idea of popping it into low range and just idling along. It all went great until the traffic began to speed up where it never normally did. And it got faster and faster. I found myself in 6th gear with the engine screaming and trucks overtaking. I could hardly stop to change back to high. It was the only time I ever saw the queue open up like that. Next day back in high range I never got above 20 on the same section.

DaveB · Mar 30, 2023

Spjnr said:
Yeah from what I heard (Aussies chime in) in OZ they caved to consumer demand and put a proper low box in the work spec ones. Shame as they're a great option otherwise here in the UK where we are somewhat starved for good tow motors.... Until now

The new Amarok is actually a rebadged Ford Ranger built in Thailand

Hicarus · Mar 31, 2023

Anyone mind if I drag you back to those two gorgeous pictures of the internals of the transfer box?

They raise several points in my mind (always assuming that they accurately represent IA’s use of this proprietary box)…….

There is no neutral position as with JLR’s version of the transfer box. The two detents on the selector rod show this.
It is the secondary selector system (arrowed) that has me puzzled. IG is a permanent 4x4 but this can only disconnect the front axle drive.

Anyone any ideas/thoughts?

Tom D · Mar 31, 2023

That’s the centre diff lock isn’t it?

CountyV8 · Mar 31, 2023

There is a nut on the side to put it into true neutral its in the manual. Not sure if you can leave the stick in the middle Ala Land Rover 110 (danger of it slipping back in) or the neutral screw holds in in neutral for flat towing.

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