A 2wd to 4wd conversion question(s) thread...

[pavelvoivoda]

Hey

The two multimode tcases are: the older is J-shift multimode with vacuum ADD, the newer one is an i-shift multimode with electrical ADD.

Your best and easiest way to go about this swap, is to install the simple J-shift tcase. Not either of the multi-mode J-shift or i-shift tcases. It is the earliest of the three. It is purely mechanical and can be installed with no need for electronics.

The locking hubs I think are obsolete unless you are chasing fuel economy of about a 2more miles per gallon, as all they would do is make the two front drive axles and front drive shaft not receive any rotation from the engine.

The idea of an ADD is to remove the inconvenience of going out of the cab and manually locking the front hubs.

The vacuum ADDs can be modified to be into engaged position and left that way. Thats all.

The whole engagement and disengagement of the front wheels will be happening in the Tcase. I know this method works, as before I installed the i-shift multimode tcase in mine, it had the regular j-shift non-multimode tcase and NO front diff ADD, without any vacuum switching valves.

It had one dash light and it engages instantly with no delay, unlike the multimode i have now...which engages when all parts align, which usually takes a second or two, but had rare occasions where it takes like 2 miles down the road!

I can send you pics on Monday of what the front diff looks like, and also here is a link that you can use to gather info on all parts that are involved in any of the setup that you would like to try. You should be able to see the diagrams on this website, unlike ToyoDIY which only certain regions of the world can.
Just select USA market and then 4Runner 1995/11-2002/08 and then the configuration you want. The '5' as in RZN185 frame code indicates it is a 4WD configuration.
The electric ADDs (i-shift) are from 2001 end of year till 2002. So anything before that you will find the vacuum operated tcases, be it multi or non multi mode (both j-shift) The electrical category contains all the info to find out what controls what.

http://toyotamarket.ru/

Hope I helped a bit
Pavel

 

[shiftmx]

Hey

The two multimode tcases are: the older is J-shift multimode with vacuum ADD, the newer one is an i-shift multimode with electrical ADD.

Your best and easiest way to go about this swap, is to install the simple J-shift tcase. Not either of the multi-mode J-shift or i-shift tcases. It is the earliest of the three. It is purely mechanical and can be installed with no need for electronics.

The locking hubs I think are obsolete unless you are chasing fuel economy of about a 2more miles per gallon, as all they would do is make the two front drive axles and front drive shaft not receive any rotation from the engine.

The idea of an ADD is to remove the inconvenience of going out of the cab and manually locking the front hubs.

The vacuum ADDs can be modified to be into engaged position and left that way. Thats all.

The whole engagement and disengagement of the front wheels will be happening in the Tcase. I know this method works, as before I installed the i-shift multimode tcase in mine, it had the regular j-shift non-multimode tcase and NO front diff ADD, without any vacuum switching valves.

It had one dash light and it engages instantly with no delay, unlike the multimode i have now...which engages when all parts align, which usually takes a second or two, but had rare occasions where it takes like 2 miles down the road!

I can send you pics on Monday of what the front diff looks like, and also here is a link that you can use to gather info on all parts that are involved in any of the setup that you would like to try. You should be able to see the diagrams on this website, unlike ToyoDIY which only certain regions of the world can.
Just select USA market and then 4Runner 1995/11-2002/08 and then the configuration you want. The '5' as in RZN185 frame code indicates it is a 4WD configuration.
The electric ADDs (i-shift) are from 2001 end of year till 2002. So anything before that you will find the vacuum operated tcases, be it multi or non multi mode (both j-shift) The electrical category contains all the info to find out what controls what.

http://toyotamarket.ru/

Hope I helped a bit
Pavel

This was very helpful. I do want my 4wd setup to engage instantly and not delay.

I am confused about one part though. Are you saying to use the old J shifter with ADD diff and modify the vacuum, or to use a non ADD diff? Also, what are the implications on the 2wd ECU that I have? I am wondering if it will cause a problem when it come to low range gearing in the trans once I switch it out for a 4wd trans, or if I have to swap in a 4wd ECU.

This statement...."I know this method works, as before I installed the i-shift multimode tcase in mine, it had the regular j-shift non-multimode tcase and NO front diff ADD, without any vacuum switching valves." What was the front diff you were using if it wasn't ADD?

 

[phattyduck]

I am confused about one part though. Are you saying to use the old J shifter with ADD diff and modify the vacuum, or to use a non ADD diff? Also, what are the implications on the 2wd ECU that I have? I am wondering if it will cause a problem when it come to low range gearing in the trans once I switch it out for a 4wd trans, or if I have to swap in a 4wd ECU.

I am running a 2WD engine/trans ECU on my 4WD swapped 4Runner. Its fine. The 4WD system is controlled by a separate computer (multi-mode) or relay (mechanical j-shift). The possible difference in transmission shift logic is way down on the list of priorities.

Also, waiting a second or two for a 4WD shift isn't a big deal. Even with the (manual) j-shift case, you still sometimes have to wait a second for the front diff to engage.

There is very little difference in performance between the "j-shift multi-mode" and the "i-shift multi-mode" The "J" portion of the shift (2HI/4HiU to 4HiL) just actuates a switch internally to the transfer case, just like pressing the center diff lock button on the i-shift cases.

-Charlie

 

[shiftmx]

I am running a 2WD engine/trans ECU on my 4WD swapped 4Runner. Its fine. The 4WD system is controlled by a separate computer (multi-mode) or relay (mechanical j-shift). The possible difference in transmission shift logic is way down on the list of priorities.

Also, waiting a second or two for a 4WD shift isn't a big deal. Even with the (manual) j-shift case, you still sometimes have to wait a second for the front diff to engage.

There is very little difference in performance between the "j-shift multi-mode" and the "i-shift multi-mode" The "J" portion of the shift (2HI/4HiU to 4HiL) just actuates a switch internally to the transfer case, just like pressing the center diff lock button on the i-shift cases.

-Charlie

So running your swapped 4wd transmission with a 2wd trans ECU has not caused any problems or dash lights? The mechanical install stuff is not difficult for me, I'm just a noob when it comes to the electrical side of the equation (but i can do stereo stuff no problem).

 

[phattyduck]

So running your swapped 4wd transmission with a 2wd trans ECU has not caused any problems or dash lights? The mechanical install stuff is not difficult for me, I'm just a noob when it comes to the electrical side of the equation (but i can do stereo stuff no problem).

Yeah, the 2WD ECU just ignores the signals from the 4WD system. A 4WD and 2WD transmission is all the same mechanically other than the output shaft, pan/pickup/filter and transfer case adapter/transfer case. None of those differences affect shifting in any way.

-Charlie

 

[shiftmx]

Yeah, the 2WD ECU just ignores the signals from the 4WD system. A 4WD and 2WD transmission is all the same mechanically other than the output shaft, pan/pickup/filter and transfer case adapter/transfer case. None of those differences affect shifting in any way.

-Charlie

Awesome! So do you think it's best to get a 4wd transmission from an 01-02 just to make sure there are no issues with my current ECU and then find a 2000 or older non multi mode j shifter?

Sorry I have so many questions, I just want to make sure I'm not buying the wrong parts as I know 01-02 4runners complicate things sometimes.

 

[pavelvoivoda]

This was very helpful. I do want my 4wd setup to engage instantly and not delay.

I am confused about one part though. Are you saying to use the old J shifter with ADD diff and modify the vacuum, or to use a non ADD diff? Also, what are the implications on the 2wd ECU that I have? I am wondering if it will cause a problem when it come to low range gearing in the trans once I switch it out for a 4wd trans, or if I have to swap in a 4wd ECU.

This statement...."I know this method works, as before I installed the i-shift multimode tcase in mine, it had the regular j-shift non-multimode tcase and NO front diff ADD, without any vacuum switching valves." What was the front diff you were using if it wasn't ADD?

Ok, so...
I recommend you use the old J-shifter, as it has no controller, but just one sensor that turns on the dash light that it is in 4x4. You can also use the multimodes - the systems can work independent of the engine control, but it depends on your vehicle setup.

But remember that this jshifter tcase is only for off road and not to be used at highway speeds. The multimodes are for that.

One thing to add to fix the confusion, is that my 4Runner is a ex UN truck and is built with minimum electronics. It has a front diff without an ADD. I dont think you can find this type of diff in the US. Not at least from a 4Runner. Members here can confirm it tho. Maybe from a different vehicle. not sure.

The vacuum or electric ADDs are not required to exist in the vehicle for it to work properly, as mine used to not have one, and it still worked with the regular old J-shifter. In the US market the ADDs, I believe, are installed to make the 4Runners a bit more economical, as you would have a few parts less that will receive rotation from the engine which would require additional energy to be rotated.(when in 2WD).

In my case, when my truck was with the old style J-shifter, even when I was not in 4x4, the whole front drive-train had to spin and add resistance to acceleration. If you add a front ADD, the front driveshaft will not be rotated by the engine as disengagement happens in the front diff and in the tcase. If you add also front driveaxle hubs to the wheels, you would eliminate the drive axles from spinning also and, when in 2WD, the truck might actually become a bit more economical, as the engine will not rotate them. (they would spin a bit because of the oils in the diffs and tcase, but it will be inertial.

But still, I had once the front ADD motor fill up with water and rust, as the breather hose got disconnected, and stopped working(because I forgot to connected ), thus not having 4x4 when I needed it. It is prone to failure when neglected.

So, if you are not chasing economy, (which isn't all that much) the easiest method to make the truck 4x4, is to simply install a front diff with ADD(electric one because it is easier to leave it forever engaged) and never connect it to anything. The disengagement will happen only in the tcase.

If you like to have the multimode, install the i-shift multi mode tcase, as you can make the whole system work and drive safer at highway speeds without worrying that you might loose control (it is safer and more versatile). But it is a lot more work - both mechanical and major wiring and it depends on your vehicle configuration. Not impossible tho, as my 4Runner now has the i-shifter and is uncomparable to the old style j-shifter road handling. I prefer it over the old style. Just to note: the i-shifter is not anymore capable offroad than the old j-shifter tcase. It only outperforms the old style on the highway and when slippery, and that's its major advantage over the old style.

Just remember to observe gear ratios in the diffs when you buy diffs, as the 2wd 4Runners usually have a faster rear diffs... with FGRs like 3.9, or faster - 3.7. There is no 3.7 front diff. Not that I know of. So if you decide to go and make 4x4, you have to swap out the rear diff with a slower FGR. Even if a 3.7 front diff exist, it is not great for offroading as it is too fast. I have 3.9 and is noticeable when softcore rock-climbing...

On mine, I didn't have to change the rear diff, as front diffs with ADDs with FGR 3.9 exist on Tacomas. I did change it tho with a 3.9 rear locker diff from a Tacoma, thanks to my dad who discovered it. And now I have the full setup. The current system is not as reliable as when I had a purely mechanical 4Runner drivetrain, but I know the system in and out and I can diagnose and fix it in a matter of minutes during offroading.

This is the prize you get when you build it yourself.

Here is the link to tcases bible! - T-case Differences (all years of 3rd gens).. transfer case, AWD, multi-mode

Also, if you want me to make a better recommendation, please let me know your truck's configuration - engine, transmission, year, catalog code (it should start with VZN185-..., or RZN185-.... then a 5letter code after that. Then I can tell you what combinations of 4x4 you can make on it and which is harder or easier.

Hope this helps you more...
I am in the plan of doing the same thing on one 2wd 4Runner here too...

 

[Venka93]

Did you ever end up finishing the swap? Curious what you ended up doing for those transfer case crossmember horns. I believe they are in a different spot in the 4wd


Sent from my iPhone using Tapatalk

 

[shiftmx]

Ok, so...
I recommend you use the old J-shifter, as it has no controller, but just one sensor that turns on the dash light that it is in 4x4. You can also use the multimodes - the systems can work independent of the engine control, but it depends on your vehicle setup.

But remember that this jshifter tcase is only for off road and not to be used at highway speeds. The multimodes are for that.

One thing to add to fix the confusion, is that my 4Runner is a ex UN truck and is built with minimum electronics. It has a front diff without an ADD. I dont think you can find this type of diff in the US. Not at least from a 4Runner. Members here can confirm it tho. Maybe from a different vehicle. not sure.

The vacuum or electric ADDs are not required to exist in the vehicle for it to work properly, as mine used to not have one, and it still worked with the regular old J-shifter. In the US market the ADDs, I believe, are installed to make the 4Runners a bit more economical, as you would have a few parts less that will receive rotation from the engine which would require additional energy to be rotated.(when in 2WD).

In my case, when my truck was with the old style J-shifter, even when I was not in 4x4, the whole front drive-train had to spin and add resistance to acceleration. If you add a front ADD, the front driveshaft will not be rotated by the engine as disengagement happens in the front diff and in the tcase. If you add also front driveaxle hubs to the wheels, you would eliminate the drive axles from spinning also and, when in 2WD, the truck might actually become a bit more economical, as the engine will not rotate them. (they would spin a bit because of the oils in the diffs and tcase, but it will be inertial.

But still, I had once the front ADD motor fill up with water and rust, as the breather hose got disconnected, and stopped working(because I forgot to connected ), thus not having 4x4 when I needed it. It is prone to failure when neglected.

So, if you are not chasing economy, (which isn't all that much) the easiest method to make the truck 4x4, is to simply install a front diff with ADD(electric one because it is easier to leave it forever engaged) and never connect it to anything. The disengagement will happen only in the tcase.

If you like to have the multimode, install the i-shift multi mode tcase, as you can make the whole system work and drive safer at highway speeds without worrying that you might loose control (it is safer and more versatile). But it is a lot more work - both mechanical and major wiring and it depends on your vehicle configuration. Not impossible tho, as my 4Runner now has the i-shifter and is uncomparable to the old style j-shifter road handling. I prefer it over the old style. Just to note: the i-shifter is not anymore capable offroad than the old j-shifter tcase. It only outperforms the old style on the highway and when slippery, and that's its major advantage over the old style.

Just remember to observe gear ratios in the diffs when you buy diffs, as the 2wd 4Runners usually have a faster rear diffs... with FGRs like 3.9, or faster - 3.7. There is no 3.7 front diff. Not that I know of. So if you decide to go and make 4x4, you have to swap out the rear diff with a slower FGR. Even if a 3.7 front diff exist, it is not great for offroading as it is too fast. I have 3.9 and is noticeable when softcore rock-climbing...

On mine, I didn't have to change the rear diff, as front diffs with ADDs with FGR 3.9 exist on Tacomas. I did change it tho with a 3.9 rear locker diff from a Tacoma, thanks to my dad who discovered it. And now I have the full setup. The current system is not as reliable as when I had a purely mechanical 4Runner drivetrain, but I know the system in and out and I can diagnose and fix it in a matter of minutes during offroading.

This is the prize you get when you build it yourself.

Here is the link to tcases bible! - T-case Differences (all years of 3rd gens).. transfer case, AWD, multi-mode

Also, if you want me to make a better recommendation, please let me know your truck's configuration - engine, transmission, year, catalog code (it should start with VZN185-..., or RZN185-.... then a 5letter code after that. Then I can tell you what combinations of 4x4 you can make on it and which is harder or easier.

Hope this helps you more...
I am in the plan of doing the same thing on one 2wd 4Runner here too...

I have a 2001 with the V6 and auto A340E trans. Catalog code VZN180L-GKPGKA

I do not drive on snowy highways here in Texas so just having a working 4x4 when offroad is what I am looking for. Sounds like I would be ok going the easier install route of a non multi mode j shifter. Also, I would likely prefer to go with an ADD front diff that is vacuum actuated instead of electronic. I don't think running a few vacuum lines to get the diff to engage/disengage would be too difficult. I'd rather not have the front driveshaft spinning at all times.

What I'm thinking so far is the 4wd system from a 2000 or older 4runner with non multi jshift transfer case and a 4wd auto trans from a 01-02 just to play it safe with my current electronics. See any issue with this route?

 

[shiftmx]

Did you ever end up finishing the swap? Curious what you ended up doing for those transfer case crossmember horns. I believe they are in a different spot in the 4wd


Sent from my iPhone using Tapatalk

Not yet. Just trying to compile final info for the components since mine being an 01 seems like it might be a little different but this has not been confirmed yet. You are correct, the trans cross member does have to be relocated and that should be the only fab work I have to do.

 

[phattyduck]

Not yet. Just trying to compile final info for the components since mine being an 01 seems like it might be a little different but this has not been confirmed yet. You are correct, the trans cross member does have to be relocated and that should be the only fab work I have to do.

There's also mods to the body around the shifter hole:

My suggestion is to get a crashed 4wd 4runner of your year. There are always little bits that you need/want that will be on the parts truck. You'll be able to sell the motor and other parts to help with the cost of the project.

I got a rolled '97 with no motor for $300... that had all the major parts I needed. I spent more than twice that in maintenance parts for the project (ball joints, fluids, seals, beer, etc.).

-Charlie

 

[shiftmx]

There's also mods to the body around the shifter hole:



My suggestion is to get a crashed 4wd 4runner of your year. There are always little bits that you need/want that will be on the parts truck. You'll be able to sell the motor and other parts to help with the cost of the project.



-Charlie

Ah, yes, forgot about the shifter cut out. Also, getting a 4runner of the same year is what I think would make this project more difficult, lol. I'm trying to make it easier if that is a possibility.

 

[phattyduck]

Ah, yes, forgot about the shifter cut out. Also, getting a 4runner of the same year is what I think would make this project more difficult, lol. I'm trying to make it easier if that is a possibility.

Not sure why you think it would be more difficult? Everything would be plug-n-play electrically. Yes, you need to replace a couple harnesses, but it would work 100% like factory. (the dash harness is probably the same 2WD to 4WD - the engine and engine bay harnesses would be different).

Even the vacuum system for ADD isn't quite as simple as you think - there is a vacuum tank in the wheel well, extra lines, two VSVs, little clips, etc...

-Charlie

 

[Venka93]

Not yet. Just trying to compile final info for the components since mine being an 01 seems like it might be a little different but this has not been confirmed yet. You are correct, the trans cross member does have to be relocated and that should be the only fab work I have to do.

Do you plan on just cutting it off and moving it or actually buying new horns?

I’m doing a frame swap and the donor frame is from a 2wd. Went to Toyota and the new horns are $250 a pop!!


Sent from my iPhone using Tapatalk

 

[phattyduck]

Do you plan on just cutting it off and moving it or actually buying new horns?

I’m doing a frame swap and the donor frame is from a 2wd. Went to Toyota and the new horns are $250 a pop!!

I had the same reaction. It isn't too hard to cut the welds and either move them or swap a set over from another frame.

-Charlie

 

[shiftmx]

Do you plan on just cutting it off and moving it or actually buying new horns?

I’m doing a frame swap and the donor frame is from a 2wd. Went to Toyota and the new horns are $250 a pop!!


Sent from my iPhone using Tapatalk

I plan on cutting them off a donor vehicle like phattyduck did. No way i'd pay that much for them.

 

[shiftmx]

Not sure why you think it would be more difficult? Everything would be plug-n-play electrically. Yes, you need to replace a couple harnesses, but it would work 100% like factory. (the dash harness is probably the same 2WD to 4WD - the engine and engine bay harnesses would be different).

Even the vacuum system for ADD isn't quite as simple as you think - there is a vacuum tank in the wheel well, extra lines, two VSVs, little clips, etc...

-Charlie

The vacuum system does sound like it would still be easier to run those few items as opposed to redoing and electrical harness, unless I'm missing something.

 

[phattyduck]

The vacuum system does sound like it would still be easier to run those few items as opposed to redoing and electrical harness, unless I'm missing something.

Yeah, though if you want the ADD to work, you still have to run some wires.

-Charlie

 

[pavelvoivoda]

Judging from your catalog code, since yours is from 2001, you most likely have the TRAC OFF switch on the left of the steering wheel. This means you have the newer more complex brake booster pump 'machine' instead of the regular older booster for the brakes. This complicates things a bit...

Since you will be installing a tcase that has no center diff to be unlocked, you have to make sure that you connect the signals from the tcase position switches, to the skid control ECU's to let it know that you are in 4x4 with locked center diff, to turn VSC system off.

It's just that the old style jshift tcase is never installed in combo with the new VSC(vehicle stability control) system, because VSC system can only assist in stabilizing the car during driving, when unlocked multimode transfer cases are installed. It is intended for highway speeds. (It is a cool system tho, and is one thing i would like to try to install on my 4Runner)

You have to connect the signals from the tcase to the VSC ECU (a.k.a. skid control ECU ) because the ECUs on both 2x4 and 4x4 4Runners that have VSC system(after end of 2000), are the same part number. The numbers only differ when there are different size tires, but the principle of operation remains the same. Here are links to both 2x4 and 4x4 4Runners schemtics to show what I mean.
2x4 - http://toyotamarket.ru/us/671460/005/4/8414/2/89540/ yours is VZN180
4x4 - http://toyotamarket.ru/us/671460/008/4/8414/2/89540/ the 4x4 version is VZN185

If you dont let the VSC ECU know that supposedly there is a locked center diff, then it may throw an error or start flashing the VSC light (different than the VSC OFF light) to tell you that there is a malfuntion and that you need to fix the issue.

This is a must.

And also - if you dont have one, you may have to connect a light bulb on the back of the dash at the right spot (behind an unlit VSC OFF icon) for the skid control ECU, to inform you that it has detected a locked center diff and will turn off that system by lighting up the VSC OFF light. You may have the bulbs already. You'll see when you open the dash.

Now, back to the TRAC OFF light - this is different light and switch that Toyota installs only on 2x4 4Runners, to let the driver turn off traction control when need be. Otherwise if you leave TRAC ON, (when no TRAC OFF light illuminates) the 4Runner simulates a limited slip rear diff. It acts a bit like a rear locker, but not quite. It's just an experiment from Toyota to make the car versatile, yet not as expensive as when with a rear locker.

If you ever want to install a rear diff locker, let me know and I will tell you how to connect the VSC ECU to know that there is a real locked rear diff locker in the back and not interfere.

It's a different topic tho for later.

For now leave the TRAC OFF function and not mess with it.

Sorry for the long reply, but it is important stuff so your ABS and VSC and EBD, and TRAC... do not interfere and throw lights and codes at you.

Here is a list if you decide to go with the old style j-shifter tcase:

An adapter/extension housing to attach the tcase to the back of the auto transmission. may be hard to source. I myself am looking for the same part, but for the W59 manual transmission...here in Bulgaria!
re-weld the cross member horns
cut out the shift lever tunnel like mentioned in this thread.
may need to find correct length drive shafts or modify them to fit
install front diff with vacuum ADD and VSV valves with wires/hoses
install vacuum tank in front of left front tire
wire signals from tcase position switches to VSC ECU to let it know to turn itself off
install a VSC OFF and 4x4 indication light in dash, if missing

I gotta go to bed but I think the list is sufficient enough
Hope it gives you a good insight into the complex VSC system which actually is a very nice system. I want to try to add it to my runner which is manual transmission and that makes things even more complex!...UUUUH!

Good night!

 

[Senza]

I also wanna do a 2wd-4wd conversion since i have to go and replace my entire 3.4 v6 anyways. i have an 01 limited stock 2wd and wanted to know if i could use any year or if i have to use the 01-02 trans. i want a j-shift for simplicity and less electrical wiring. plus j shifts are always better in my opinion. so i wanted to know if it’s possible at all, if i can use any 3rd gen 4wd auto trans, what other components i would need, and if the j-shift is possible on my model since it’s 4wd counterpart is built for the electronic shifter.