V8 AWD to Part-Time Conversion?!

[CAN-AM]

I've being faced with the same dilemma as most... V8 AWD or V6 part-time.

The V6 has adequate power, however I'm concerned with a lift and oversized tires the performance will suffer. In a perfect world (in my opinion) a V8 part-time system would be ideal. NOTE: I’m not intending this post to be a debate between V8 or V6!

Considering the AWD and part-time systems are identical, just one is one all the time, would it not be possible to convert the AWD system to part-time? I'm assuming everything is electronic and the installation of a switch or actuator would do the trick. Any experts or opinions on the matter?

Thanks for your input!

 

[Loki]

should be possible unless the bigger v8 engine gets in the way of some parts needed to do it. interesting thought though. i wonder why they all aren't switchable from the factory.

 

[boston_kevin]

Transfer case conversion

If you wanted to convert from AWD to Part-Time 4WD, you would have to change the transfer case and possibly the shafts (and joints) depending on the dimensions of the new case. Then install the electronics to operate the case and hook up the sensor to determine which mode you are in.

My guess is that the transfer case for Part Time 4WD is bigger and won't fit with the V8.

 

[CAN-AM]

Boston_Kevin

The AWD and Part-time 4WD systems are IDENTICAL (i.e. same transfer case, same axles, same sensors, same transmission...). The only difference is that the AWD is on all the time.

I was thinking that the 2WD-4WD switch used on the V6s could be installed on the V8s allowing multi-mode.

 

[gonzo]

that would be terrific. i would also be interested in switching the VSC off, with out having to lock the center diff, and being able to disengage the traction control system. i find it very frustrating when the traction control system won't let me tear through the sand or the snow.

 

[boston_kevin]

"Boston_Kevin

The AWD and Part-time 4WD systems are IDENTICAL (i.e. same transfer case, same axles, same sensors, same transmission...). The only difference is that the AWD is on all the time."

If this is true, then there is a wasted servo on the AWD Transfer cases. I don't think Toyota would put this in there unless they wanted it used. Have you torn apart the Transfer case to confirm that this is actually there? If the servo is there, you just need to power the servo to change to the appropriate gear in the Transfer case and the sensor to determine if you are in 4WD or 2WD.

 

[Good Times]

First off our 4runners are not awd. It's a fulltime 4wd system. Remember that an awd system does not have the 4LO feature. This seems to be a common mistake by alot of people since they know it's a full time system. awd systems are found on volvo's, subaru's etc etc. We get that extra 4lo for the umph that the others don't have! hehe

I would think that this would be possible. I would suggest you pulling the transfer case from the v8 sequoia or tundra. I don't think you'll be able to use your existing transfer case because it won't disengage the front at all. (I believe the tundra would be better as their equipment is all electronic whereas sequoia is still stick in the center (i think unless the sequoia is all electronic now - never checked so i can't say)). You'll want to change out the driveshafts if they are a different length and also swap out the ecu. Since the motor is the same the rest of the electronics should match up but I can't be certain. you will also want to swap out the center switch that controls the part time dial to the v6 model and then make sure you get the proper wiring harness associated with it. The good thing is you can actually use all the v6 internal wiring harness and piggy back it to your new ecu which I believe should work (dunno). If all else fails you can just splice lines and attach it directly to the new ecu.

You shouldn't have any problems with the abs or vsc or the atrac as they are not dependent on the 4wd system itself (meaning it can be full time, part time the ecu won't care).

On a side note, even if you had the v6 or v8, if you got a lift and larger tires, you'll suffer the same performance issues. You will gain the performance back by regearing. Unfortunately there are no aftermarket gears yet but I'm sure those will come in time. I hear 05 is a great year for us in the aftermarket world so woohoo!

it would be alot of work but possible. might be too much trouble per say but if you're up for the task i see why not.

good luck

 

[EDGE]

I might only be 25 but what happened to the good old days, now in order to swap something you need the ECU, wiring harness, the right switches

What happened, my older friends tell me of the times when they just dropped in a big block and a new trans bolted it up and drove it

Eventually your gonna have to get authorization from the manurfature to even change an air filter:nerd: nowonder some of the older more modable cars are going up in value:awais:

 

[TechWrench]

I might only be 25 but what happened to the good old days, now in order to swap something you need the ECU, wiring harness, the right switches

What happened, my older friends tell me of the times when they just dropped in a big block and a new trans bolted it up and drove it

Eventually your gonna have to get authorization from the manurfature to even change an air filter:nerd: nowonder some of the older more modable cars are going up in value:awais:

Thats progress!!!

No manufacturer wants to fall behind in the technology race, and it seems like most people want the latest/greatest gee wizz gizmos, so thats what they give us. Lets face it, it ain't never going back to the 'good old days'.

 

[Thai]

I think that the "conversion" will cost a lot of $$$$$, time, and labor. That $$$$$ (time & labor) can be saved to buy the tiny extra bit of fuel for your V8 for the rest of the life of your 4runner.

BTW, some owners claim that full-time 4wd (both V6 and V8 models) promotes more even tire wear than if you were to leave it in 2wd. Thus, another argument to save your $$$$$.

 

[dcampen]

Full time 4WD

The AWD and Part-time 4WD systems are IDENTICAL (i.e. same transfer case, same axles, same sensors, same transmission...). The only difference is that the AWD is on all the time.

I am not sure how you came to this conclusion. I believe that the V6 transfer case has the mechanical means for disconnecting the front drive shaft while the V8 transfer case does not.

 

[CAN-AM]

You are correct. I'm not expert, that's the reason for my post.

Does the V6 models disconnect at the hubs or at the transfer case?

I guess like everything in life... things get complicated real quick.

One last question... how old is the 4WD systems? Is it the same system used (or still in use) in the Lexus?

Thanks!

 

[dcampen]

I am pretty sure that the front wheels are disconnected in the transfer case not the hubs.

The transfer case is an integral part of the Torsen limited slip differential.

What would be really nice is if both the V6 and V8 could have all wheels disconnected at the transfer case for being towed as you can do with Jeeps.

 

[bulldog-yota]

Does somebody have a V6 repair manual? I think the V6 would still have ADD on the front wheels. If you dont disconnect the driveshafts on the front wheels it doesn't really help to disconnect the front prop shaft at the transfer case. So to convert the V8 to part time 4WD you will need to look into the front hubs as well.

 

[TechWrench]

After looking at the '05 specs on the Toyota site, it looks like both the V6 and V8 now come standard with the 5-speed auto. (apparently the 4-speed trans is no longer available) But the V6 still has the part time transfer case and the V8 has the full time transfer case. (PT 4WD doesn't appear to be an option on the V8)

http://www.toyota.com/vehicles/2005/4runner/specs.html

I am pretty sure the transfer cases are not 'identical' internally, but it might be possible now to switch them (though I imagine it would be a very expensive MOD).

 

[ToolmanJohn]

Re the tires wearing faster

I am under the immpression that the front and rear differentials are open. Isn't that true? So being open, you won't get accellerated tire wear unless you have a lead foot. The ATRAC system controls wheel slip using the brake system, the new 4runners do not have limited slip differentials.

So having an open differential will allow the tire on the inside of a turn to rotate slower, no increased wear because of binding. This is how we get a nice "full" time 4WD systems on both the V6 and V8, which can be on 100% of the time on any road surface. I don't really understand why the V6 vehicles don't have the full time system like the V8. Can anyone think of a reason for a selectable system on the V6 versus the full time system on the V8? I can't.

 

[MicaBlue03]

Reason for the multimode system

ToolmanJohn, I've found I like the way the 4Runner handles and feels in 2WD a little bit better. It's been discussed in other (V6 vs. V8) threads so I won't waste bandwidth here. The handling difference may have to do with front-to-rear weight transfer under acceleration or the ability to devote the front tire traction patches exclusively to steering, or to something else. Maybe the traction load causes the front suspension to behave differently.

There's also the driveline efficiency issue, where fewer parts need to be spinning in 2WD, and perhaps less wear or fewer repairs on expensive front end driveline parts.

It's not a really big deal, but I'm glad I have the multimode system.

There is a downside to the multimode system in slick conditions, though. If you don't remember to put the system in 4WD befor you're stuck, you may not be able to do so once you are.

 

[24runners]

on my 96 4wd, when I put it in 4wd high i couldnt "do a sharp u-turn" because it wouldnt want to let the outer wheels turn faster than the inside ones...on my 05 full time awd it allows for that...

i'm pretty sure the multi-mode 4wd setting has a locked diff and the full awd system is open until it is locked to become 4hi (and not awd)

 

[bulldog-yota]

My understanding is thet the V6 also has a Torsen center diff in the transfer case. Which means it will behave exactly the same at the V8 in 4wd setting.

This means you can swap the transfer and some ecltrics for the transfer case for the V8 to allow the same funtion as on the V6. However to really make a difference the front whell hubs also need to be disconnected in 2wd. This is why I suspect the V6 has ADD (auto disconnect hubs) on the front wheels. This will be a big pain to change for the V8. I also suspect there is a real reason why the V8 doesn't have 2wd function, maybe the extra torque and weight on the front is above the rating of the ADD system???

 

[MicaBlue03]

V6s have different differential assembly

Bulldog-Yota I think you are correct about the front end disconnects. The V6 repair manual supplement (2003) describes a "differential vacuum actuator assy" and associated "slide gears" that are part of the right hand side of the differential housing.

The V6 & V8 both have Torsen, etc. so the driveline differences appear to be mainly the addition of the disconnects in the transfer case and front differential to allow for the 2WD mode.

I wondered if the 4WD only mode was used in the V8 due to the greater torque it can produce, but since they make a 2WD V8 4Runner that would indicate otherwise. Perhaps they didn't want to add the extra weight of the disconnect stuff to the front of the V8 4Runners since they're already heavier (with the heavier engine). That doesn't seem likely, but I can't think of a really good reason other than potential cost savings (to help reduce the price differential on the two versions).