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

[shiftmx]

During a conversion, at what point do you have to swap out electronics? I would like the swap to be completely mechanical and leave all the stock electronics alone if possible. ALso, I want this to remain IFS, not really interested in the fabrication of going SAS.

P.S. Before the comments of "sell your 2wd and buy a 4wd"...I tried that and at the $6000 price tag of neglected 200k mile 4runner 4x4s, I'd rather just spend about $1500 -2000 and go over every component as I put it in. The transmission on mine will likely need to be replaced in the near future and figure its a good time to perform the swap.


***Reviving my old thread.***

I'm in a good position to be able to do this and it looks like using Tacoma manual hubs would be the best way to do this and retain my factory 2wd ECU. So just to be clear, using a J-shifter TC and Tacoma manual hubs would not need any additional wiring...am I correct on this?

 

[phattyduck]

You can do all of the mechanical work on the 2WD to 4WD swap before changing electronics. Stick with going for a j-shift (not multi-mode) if you want the minimum of wiring (its about 10 wires total that way).

I re-geared the rear one day, did the front components another day, then the transmission and crossmember on a 2-day weekend, then the wiring after that.

A parts truck will be the easiest route to go... See the link in my sig for my build thread.

-Charlie

 

[shiftmx]

What did you have to wire? If I try and find non-ADD parts, would I still have to wire something?

 

[Chuckles89]

If you find tacoma manual hub parts, you won't have to wire anything (unless you want a 4WD light on the dash)

 

[phattyduck]

If you find tacoma manual hub parts, you won't have to wire anything (unless you want a 4WD light on the dash)

Bingo.

If you want to do a bit of wiring though, the stock dash harness has all the wires for the 4WD system that would be in your truck from the factory. It is only the engine harness and harness to the engine bay fuse box that differs, based on what I have seen so far.

If you just want to get the green light on the dash (and have manual hubs), you only need 2 wires - one up to the right pin in the dash and one ground, connected to the "4WD" switch on the transfer case.

-Charlie

 

[MandAtaco]

I've been kinda looking at this because I'm changing from a multi-mode case to a J-shift. I have to remove my multimode computer and rewire it for a standard J-shift.

If you do end up running a ADD differential, at least on the early one that is vacuum controlled, all you need to turn it on and off is a 5 pole relay. Basically a switch on the transfer case completes the ground of the relay, sending 12V from the "off" vacuum switch to the "on" vacuum switch. When 4x4 is disengaged on the transfer case, the ground is removed and the relay defaults back to the "off" vacuum switch.

Adding a dash light works the same way. Transfer case completes ground, ground goes to front differential on/off switch, when that switch closes, the ground circuit is completed to a light bulb.

 

[TheDurk]

I've been kinda looking at this because I'm changing from a multi-mode case to a J-shift. I have to remove my multimode computer and rewire it for a standard J-shift.

If you do end up running a ADD differential, at least on the early one that is vacuum controlled, all you need to turn it on and off is a 5 pole relay. Basically a switch on the transfer case completes the ground of the relay, sending 12V from the "off" vacuum switch to the "on" vacuum switch. When 4x4 is disengaged on the transfer case, the ground is removed and the relay defaults back to the "off" vacuum switch.

Adding a dash light works the same way. Transfer case completes ground, ground goes to front differential on/off switch, when that switch closes, the ground circuit is completed to a light bulb.

Just to be clear, the bolded is true for the push-button circuit. It is worth noting that that ground permission is routed through the 4WD computer. However, in the J-shift, there is no electrical connection on the TC to the indicator light circuit, since the vacuum is only engaged when the 4WD position switch on the TC closes. There is also no 4wd computer. The light simply goes on when the vacuum causes the front diff to engage and closes the front diff position switch providing ground to the light. That front ADD switch is the only switch in the J-shift 4wd light circuit. Source: My 1999 paper EWD manual.

Sorry to be picky, but it makes a difference if you are trying to fix or switch to a J-shift.

 

[MandAtaco]

Just to be clear, the bolded is true for the push-button circuit. It is worth noting that that ground permission is routed through the 4WD computer. However, in the J-shift, there is no electrical connection on the TC to the indicator light circuit, since the vacuum is only engaged when the 4WD position switch on the TC closes. There is also no 4wd computer. The light simply goes on when the vacuum causes the front diff to engage and closes the front diff position switch providing ground to the light. That front ADD switch is the only switch in the J-shift 4wd light circuit. Source: My 1999 paper EWD manual.

Sorry to be picky, but it makes a difference if you are trying to fix or switch to a J-shift.

No issues man, I've been looking at this stuff for a week so I wanna make sure its right when I do the change over.

Yup, no computer on a J-shift set up. Maybe I'm reading this wiring diagram wrong then, or its for a different year. The way I'm reading it, it goes from ground to the 4wd selector switch, splits up to the Engine ECU and to the ADD indicator switch, then to the light bulb.



Honestly, all I really want to know from the light is if the front diff is "in" or "out". If they lever on the Tcase is in the right spot, I know its in the right spot!

 

[TheDurk]

No issues man, I've been looking at this stuff for a week so I wanna make sure its right when I do the change over.

Yup, no computer on a J-shift set up. Maybe I'm reading this wiring diagram wrong then, or its for a different year. The way I'm reading it, it goes from ground to the 4wd selector switch, splits up to the Engine ECU and to the ADD indicator switch, then to the light bulb.



Honestly, all I really want to know from the light is if the front diff is "in" or "out". If they lever on the Tcase is in the right spot, I know its in the right spot!

OOPS. I take it back. I looked at it too quickly and decided it showed what I THOUGHT was the case. My sincere apologies. 1999 is quite different though, but not in that respect. The "except Cali." leads me to believe that yours must be the 2000. 1999, even though Cali's existed, has no separate diagram.

Like you, I see no reason it has to be that way. How often will the TC not engage if the J-lever is in position for 4wd? More to the point, how often will the ADD engage if the TC has not? Wouldn't you prefer to know that it has, when you were not expecting it to? As in, if you have a VSV fail and vacuum stays on in 4wd while the J-lever and TC are in 2wd, the light will go out because the TC goes out, while your front diff stays locked and you won't know until you do a turn on a hard surface. Hummmph. They really should have done it my way!

 

[MandAtaco]

Headed out now, I'll see if I can find what I got this one for.

 

[Toyotayoda]

During a conversion, at what point do you have to swap out electronics? I would like the swap to be completely mechanical and leave all the stock electronics alone if possible. ALso, I want this to remain IFS, not really interested in the fabrication of going SAS.

P.S. Before the comments of "sell your 2wd and buy a 4wd"...I tried that and at the $6000 price tag of neglected 200k mile 4runner 4x4s, I'd rather just spend about $1500 -2000 and go over every component as I put it in. The transmission on mine will likely need to be replaced in the near future and figure its a good time to perform the swap.

Looks like I should try to sell my 3rd gen in TX an buy a 4th gen in GA. I bought mine @ 269k for $2400, fixed valve covers, full ign tune up with toyota parts, all belts, hoses, WP just done again with toyota parts, BIlstein 4600's all around. Just bought a 1" body lift and 17" 5th gen take offs. guaranteed to never sell in GA, but heck not that far to TX. I think a donor vehicle might be your best bet, you'd get everything you need+ some extra body parts before scrapping a shell for a few bucks.

 

[MandAtaco]

OOPS. I take it back. I looked at it too quickly and decided it showed what I THOUGHT was the case. My sincere apologies. 1999 is quite different though, but not in that respect. The "except Cali." leads me to believe that yours must be the 2000. 1999, even though Cali's existed, has no separate diagram.

Like you, I see no reason it has to be that way. How often will the TC not engage if the J-lever is in position for 4wd? More to the point, how often will the ADD engage if the TC has not? Wouldn't you prefer to know that it has, when you were not expecting it to? As in, if you have a VSV fail and vacuum stays on in 4wd while the J-lever and TC are in 2wd, the light will go out because the TC goes out, while your front diff stays locked and you won't know until you do a turn on a hard surface. Hummmph. They really should have done it my way!

This! I more care about what the front diff is doing than the transfer case, I know which direction the handle is pointed! Now that I think about it, I could wire the transfer case to the "center diff light" and the front diff to the "4x4 light" I do have two lights on the dash since I originally had the multimode case. Hmmm. Much to ponder. Thanks!

 

[shiftmx]

I don't mind wiring a light to indicate 4wd is active, but I wouldn't add it in my cluster. Maybe just a small light somewhere on a removable dash panel kind of like a car alarm indicator.

Does anyone have or can point me to a comprehensive list of parts needed for a for a non-ADD swap? Also if all I can find are ADD parts, is the swap much more difficult?

 

[shiftmx]

Reviving my old thread.

I'm in a good position to be able to do this and it looks like using Tacoma manual hubs would be the best way to do this and retain my factory 2wd ECU. So just to be clear, using a J-shifter TC and Tacoma manual hubs would not need any additional wiring...am I correct on this?

 

[Taylor20]

COB's 4Runner Timeline (Pic Heavy)

Best source for your adventure.

 

[shiftmx]

COB's 4Runner Timeline (Pic Heavy)

Best source for your adventure.

Thanks for the link. While a great mechanical source, it doesn't answer any questions about the electrical side of things. I have a '01 and it seems the ECU/electrical is different than previous years. When I search for parts on car-part.com, I can only get transmissions from 01-02 4runners, so I'm thinking I might have a problem if I try to get a J shift TC from a different year.

 

[TheDurk]

Reviving my old thread.

I'm in a good position to be able to do this and it looks like using Tacoma manual hubs would be the best way to do this and retain my factory 2wd ECU. So just to be clear, using a J-shifter TC and Tacoma manual hubs would not need any additional wiring...am I correct on this?

Correct. Obviously, you will have no dash light, like all manual hub vehicles that I have ever seen.

 

[phattyduck]

Reviving my old thread.

I'm in a good position to be able to do this and it looks like using Tacoma manual hubs would be the best way to do this and retain my factory 2wd ECU. So just to be clear, using a J-shifter TC and Tacoma manual hubs would not need any additional wiring...am I correct on this?

If you want to lock the ADD in place (or get a non-ADD diff tube/stub axle), you can get away without any wiring. Otherwise, wiring the ADD to engage when in 4WD is pretty simple...

There are supposedly some shift logic changes for when you are in 4LO, but otherwise, a 2WD would run a 4WD transmission just fine. There are also some differences in the ABS/Traction control systems for 4WD's that might be of issue on the 01/02's.

-Charlie

 

[shiftmx]

There are also some differences in the ABS/Traction control systems for 4WD's that might be of issue on the 01/02's.

-Charlie

This is the part that worries me. Every conversion I have seen was for a 2000 or older. I have a feeling that wherever changes they made in 01-02 are really going to mess this up. My only chance may be to use the 4wd system from the same years, but I was hoping not to have to change wiring harnesses.

 

[phattyduck]

This is the part that worries me. Every conversion I have seen was for a 2000 or older. I have a feeling that wherever changes they made in 01-02 are really going to mess this up. My only chance may be to use the 4wd system from the same years, but I was hoping not to have to change wiring harnesses.

Check under the dash for plugs for the 4WD computer, etc. You may be pleasantly surprised. My 2WD has the same wiring harness under the dash an SR5 4WD (rear locker plug, ADD plug, etc.).

01/02's had electronically actuated ADD systems (instead of the earlier vacuum system), and all of them are multi-mode.

Your best bet here if you are really serious about doing the 4WD swap and keeping your 4Runner is to find a rolled/crashed 01/02 4WD and start swapping parts over!

-Charlie