Anyone retrofitted in a pathfinder transfer case?

[ryzan]

Some r51 pathfinder models run a hydraulic transfer case rather than just a mechanical transfer case like ours, this allows them to run in 2wd mode, on road 4hi or off road (locked) 4h, as well as locked 4lo. Has anybody ever looked in to see if this can be swapped in to a d40 before?

 

[Old.Tony]

You'd need the hydraulic assemblies as well. Not even sure if there are mounts for that on the D40.

By the sounds of the variations you're describing, the transfer case in the Pathy has a limited slip diff built in o the car can be driven full-time in 4WD on any surface. Usually when we say "locked" we mean the driveline at that point is totally engaged and its output is forced to rotate in line with its input. This means that "unlocked" allows some freedom - like an LSD.

Am I understanding that correctly? It might be interesting to see if an R51 TF can go in the D40 then!

 

[ryzan]

From what I've read on the pathfinder forums, there is an electronic pump inside the transfer case that runs it under 30kmh or 30mph (can't remember which), and then it runs off a pump connected to the transmission output shaft over those speeds. Only thing would be possible length differences of the transfers, and any associated electronics to go with it.

I thought it'd be pretty nifty to be able to shift on the fly when you have a bit of a difference in axle speed (as the hydraulics should progressively apply drive to the front as it builds pressure) rather than having to have the axle speeds matched. Had an issue where I found some soft sand on the beach the other month and had too much wheelspin in the back (stupid I know). But if the hydraulic system could overcome that I think it would be pretty nifty. Also having the ability to run in 4 wheel drive but not worry about driveline wind up would be nice as well.

 

[ryzan]

http://www.thenissanpath.com/viewtopic.php?t=6907

 

[Old.Tony]

The ATX14B sounds like an awesome TF to have, especially if it can manage slip between front and rear drive shafts.

I wonder how much of that is controlled externally? If everything's managed from inside the TF, then the only problems I can see fitting it to a D40 are:

1) Wiring - apart from having to install extra wiring for power to cater for the electric pump, our switch sends electrical signals to the ECU which then instructs the transfer case to change gear. This is why if you send the signal manually to the servo (as Raptorthumper did with his STX550 to defeat the 4LO upshifting problem) the car has no idea it's in 4WD, even though it is. We'd need to be sure that the signals our car sends to the TF are the same. We also don't know where the TF picks up the speed measurement for switching off the electric pump.

2) Physical size. The auto TF has a lot more in it - two pumps, a wet clutch and I'd wager a fair bit more oil. Someone'll have dimension on it - our TF isn't exactly small, but this one sounds a fair bit bigger. Does it mean our drive shafts will need to be cut?

Be interesting to get those answers.

 

[ryzan]

Well from what I've (quickly) gathered, capacity is about an extra litre of oil in the t/f. My guess is the std driveshaft would either need to be shortened or extended (or have a spacer fitted) or possibly modified depending on whether it uses the same spline count on the output shaft.

At a guess even if you had to swap out transmission harness and computers it still shouldn't be too hard considering they're basically the same vehicle pathfinder to spain nav (and you use same/similar years). That said though one thing I've learnt from Nav ownership is that Nissan tried to make every model Navara different (unlike most other vehicles that come off a production line).

Lots of interesting questions that I'm guessing someone on the pathfinder forum might be able to answer a bit better.

 

[Old.Tony]

I agree. You'd have to check function - if you're replacing the ECM, you need to make sure that it's compatible with the BCM fitted and the TCM in the gearbox (which SHOULD be the case, since they've used the same auto box for years and only changed it in 2011 for the 550 and 2012 for the D40 2.5).

The decision to shift the TF isn't made in the gearbox, in our cars it's driven by the command from the driver (switch) with a check for vehicle speed, ABS sensors intact - the transfer relays (in the box behind the battery) are then activated sending power to the servo mounted on the transfer case. The TCM (in the auto, it's with the valve body in the bottom of the box) doesn't have a say at all as far as I'm aware. It might feed data to the ECU in the form of expected output revolutions (-> expected speed, compare to ABS signal), current gear - from my understanding, it doesn't actually use the TCM to note the gear when selecting 4LO either, that's done purely by the Park/Neutral switch which is independent of the TCM.

 

[ryzan]

Well after having a read through the pathfinder's owner manual it appears that the hydraulic coupling doesn't like shifting between 2 and awd modes when there is a difference between front and rear axle speeds either. Looks like for me it might be easier to just stick with what I've got and spend that money on a locker or something instead.