I have had my MY24 L663 110s P300 for a few month and love it.

I recently found that JLR has put "i AWD" to all the L663 starting MY23. I confirmed that my P300 has a transfer case same as that of a MY20 diesel 3.0. So, I have i AWD system with my P300.

Any one knows how is this "i AWD transfer case" different from the "older one" which is [ [b]permanent AWD with a bevel gear style center differential and lockable with a muti-clutch pack]? I am more interested in the mechanic difference between the two, to satisfy my "gear-head" curiosity.

I hope some one here also having similar interest and I can learn something.

Thanks

 

JLR hasn't provided any technical info on the updated transfer case, but everything is very similar other than the fact that the new transfer case has an extra clutch pack that allows the front axle to be disconnected under certain conditions. The center differentials are electronically-controlled and have two clutch packs per differential on both the old permanent system and the current iAWD. The clutch packs allow the center (and rear) differentials to be infinitely variable (not completely open or locked, but allows for open, locked and multiple degrees of partial lock), which allows for excellent drivability and traction. It is also completely seamless and operates in the background, and you don't even notice them working while you're behind the wheel. One of the positive aspects of this new system is that if you damage your front driveshaft, you will still be able to get home, because the rear axle will still be driven. In the old system, this wouldn't work and you'd be stuck. In terms of off-road capability, there isn't one that is better than the other. The new one has a variable torque split, which can help in certain situations, but overall they are nearly identical off-road.

The electronic differentials have had the same layout for 20 years now, and the only have gotten better with every generation.

 

This is what the "old" transfer case is look like.
My understanding is that the only multi clutch pack (3) is activated to lock the differential (8) to the drive chain sprocket (54) to front axle.

I wonder if any one have ever seen a similar diagram like this for the newer, i-AWD transfer case. I should think this diagram for the newer one be available from a dealer shop, for the diesel 3.0l Defender has had it since the beginning.

But I never find one.

This is the link where I found this diagram
https://www.lrdefender.org/description-677.html

 

the 3.0 diesel has not been around since the beginning. The 2020MY started off with the 2.0 Ingenium diesel, which had the old transfer case. The 3.0 Ingenium diesel arrived for the 2021MY to replace the 2.0 Ingenium, and was the first to get the new transfer case with Active Driveline.


You’ll probably have to purchase a shop manual on Topix or ask a dealer to see if they would be willing give you a copy of it or a parts diagram if it matters that much to you.

 

Many thanks for your input. Appreciated.

 

This img was posted in a different thread or forum recently and I saved it down (apologies for not crediting who I can't remember). It's not as detailed as the cutaway you're hoping for, but still pretty interesting to see the overall differences between the two.

 

I know very little about 2016+ LRs, and just starting a mechanical engineering degree, so apologies for the stupid questions. I'm also super curious too about the differences too. I noticed on the image there's a second clutch on the front axle disconnect unit, whereas the previous just has a disconnect unit. Would you have to switch out the axles to do a swap? Also, what is the purpose of the axle disconnect unit, and why only on the one side? Seems like adding more clutches and parts would only decrease the reliability? curious if this is/will be a common failure point.

 

Both of those diagrams (green and red highlights) are the same system illustrating two modes.

There can’t be a disconnect in the older system since the open center differential would require locked clutches to move when the front axle is disconnected. Swapping the front axle with a disconnect wouldn’t work.

Yeah, more parts to wear and complexity. While this doesn’t always mean less reliable it will be another set of wear and maintenance items. Hopefully that 1.7% better mpg and lower NVH is worth it.

 

The change happened around the model year 23.5. The original design stated above does have a center differential variable locking. There is no front axle disconnect. To put it simply if you break any of the four axles, vehicle is no longer mobile. In the model 23.5 and up, the vehicle is permanent rear wheel drive with torque on demand front drive. This means there is no longer a center differential. If you break one of the front axles, the vehicle will still move. The vehicle will also still move even with the front drive shaft removed. If you break a rear axle, the vehicle will be not movable. I believe this is an improved system in regards to failsafe operation. Let's say for example you install one of our selectable rear lockers in a newer vehicle, technically you can break any of the four axles and still be able to drive off the trails. These newer vehicles also don't exhibit some of the bucking that can be seen off-road when the rear wheels get chocked. The system does seem to take power away from the rear axle at times since it is a differential-based system. The newer system does not exhibit this since the rear axle is always driven. I did notice driving a stock p300 with the newer system does seem to have at least a couple miles per gallon fuel economy improvement which may be related to the front axle disconnect. Another benefit to the newer system is that both the left front and right front axles are the same part number. There's no longer the super long stuff axle on the right side which makes axle replacement a lot easier. Also note that the p300 originally had 8HP45 ZF transmission. They upgraded after the 23.5 model year to a 8HP51 I believe p400 was also upgraded. The only idiotic thing JLR did was to remove the neutral release cable on the newer ones. This can definitely be a major pain if needing to tow the vehicle. It looks like the provisions are there to connect a cable, so we are working on a retrofit kit to bring the neutral release cable back for the newer vehicles

 

There got to be a planetary gear set to do the two speed in this newer case. So, the rear propel shaft is directly driven by the gear set?

I have a feeling that there could be two multi clutch pack at both side of the gear set, one for front propel shaft, the other for the rear, some thing like what the current Audi S3 has as for its rear "diff", which they did not call it diff, some thing else. Youtube shows it quite clear.

The seemingly rigid/all ways driven of the rear can be realized by the "always on" of the multi clutch pack for the rear side.