FJ Transfer Case Swap into a V6 4th Gen

[xtremewlr]

I've not experienced any binding in either 2WD or 4WD with the FJ case and the AWD front axle.

 

[ryanking61]

Day 1 Update

So little update after today. No where close to being done. I’m learning that most people have done this with the V8 that has the longer 5-speed transmission. Since I have the 4-speed, everything is farther forward and everything is in the way. Lots of cutting and tough decisions. Spent 4 hours just getting the shifter positioned how I want. I’ll post pics tomorrow, hoping to get it done tomorrow as well.

 

[BlackWorksInc]

Also, why would there be binding in 2WD?

I've not experienced any binding in either 2WD or 4WD with the FJ case and the AWD front axle.

So two things.

First, it does seem like the FJ Cruisers with 6spd Manual Transfer Cases did come with the T3 Torsen in them (which makes sense now that I think about it since they were All-Time 4WD, my apologies.)

Second, the binding occurs in 4WD on turns most noticeable close to lock. The reason for this is because the drivetrain can't slip internally so it binds up a bit when turning. This is part of the reason why the ADD system exists and why the T3 Torsen was put in the All-Time 4WD transfer cases, between disconnecting the front differential internally to allow the left and right axles to spin independently of the ring gear assembly, and the T3 Torsen allowing something like about 20% slippage front to rear this provides enough slip in the drivetrain that you don't notice any binding on turns in 4hi.

If you've ever driven an old domestic truck in 4WD or a newer non-limited 5th Gen in 4Hi on dry pavement while doing a tight turn you'll feel what I am talking about in regards to the slight binding, not a super big deal; but a bit annoying.

 

[xtremewlr]

So two things.

First, it does seem like the FJ Cruisers with 6spd Manual Transfer Cases did come with the T3 Torsen in them (which makes sense now that I think about it since they were All-Time 4WD, my apologies.)

Second, the binding occurs in 4WD on turns most noticeable close to lock. The reason for this is because the drivetrain can't slip internally so it binds up a bit when turning. This is part of the reason why the ADD system exists and why the T3 Torsen was put in the All-Time 4WD transfer cases, between disconnecting the front differential internally to allow the left and right axles to spin independently of the ring gear assembly, and the T3 Torsen allowing something like about 20% slippage front to rear this provides enough slip in the drivetrain that you don't notice any binding on turns in 4hi.

If you've ever driven an old domestic truck in 4WD or a newer non-limited 5th Gen in 4Hi on dry pavement while doing a tight turn you'll feel what I am talking about in regards to the slight binding, not a super big deal; but a bit annoying.

OK, I see what you are getting at now.

Yes, the manual 6 speed FJ case has the center differential, much the same as the 4th gen AWD transfer case found in the V8s, which is what I replace. However, the manual 6 speed FJ transfer case will not work for this swap, so don't even bother thinking about it. Different input shafts that are not interchangeable.

All 4WD systems have some binding when driven in 4WD. This is not the same as an AWD system, which generally have some sort of center differential system to allow for slip and prevent the binding that you are talking about when driven on pavement.

True 4WD systems are not generally designed to be driven on pavement for lengths of time. You can notice binding driving in 4HI on pavement but as you said, it's usually only when you have the wheels cranked to almost lock. Offroad, you will almost never notice binding because dirt/sand/mud/snow will allow for wheel slip, therefore preventing the binding. This is not a concern as the systems are designed to work this way.

Now here's the thing. ADD doesn't prevent the binding you are talking about when you are in 4wd. ADD ONLY disconnects one of the axles from the differential, the passenger side in Toyota's case, to allow the front differential to basically free wheel and prevent the binding. This only happens in 2WD. If you are in 4WD, you essentially have the same front axle that my previously AWD 4Runner has. Not as strong but they work the same way. ADD doesn't just randomly unlock and then lock again if there is binding present.

 

[xtremewlr]

So little update after today. No where close to being done. I’m learning that most people have done this with the V8 that has the longer 5-speed transmission. Since I have the 4-speed, everything is farther forward and everything is in the way. Lots of cutting and tough decisions. Spent 4 hours just getting the shifter positioned how I want. I’ll post pics tomorrow, hoping to get it done tomorrow as well.

Oh man, didn't think about the 4 speed auto being a little shorter than the 5 speed. Don't later year V6 4runners have the 5 speed? I thought the 4 behind the V6 was limited to like 2003/4 and maybe some of 2005?

All V8 4runners have the 5 speed, fortunately for us.

Looking forward to the updates, really interested to see the different challenges with it.

 

[BlackWorksInc]

OK, I see what you are getting at now.

Yes, the manual 6 speed FJ case has the center differential, much the same as the 4th gen AWD transfer case found in the V8s, which is what I replace. However, the manual 6 speed FJ transfer case will not work for this swap, so don't even bother thinking about it. Different input shafts that are not interchangeable.

All 4WD systems have some binding when driven in 4WD. This is not the same as an AWD system, which generally have some sort of center differential system to allow for slip and prevent the binding that you are talking about when driven on pavement.

True 4WD systems are not generally designed to be driven on pavement for lengths of time. You can notice binding driving in 4HI on pavement but as you said, it's usually only when you have the wheels cranked to almost lock. Offroad, you will almost never notice binding because dirt/sand/mud/snow will allow for wheel slip, therefore preventing the binding. This is not a concern as the systems are designed to work this way.

Now here's the thing. ADD doesn't prevent the binding you are talking about when you are in 4wd. ADD ONLY disconnects one of the axles from the differential, the passenger side in Toyota's case, to allow the front differential to basically free wheel and prevent the binding. This only happens in 2WD. If you are in 4WD, you essentially have the same front axle that my previously AWD 4Runner has. Not as strong but they work the same way. ADD doesn't just randomly unlock and then lock again if there is binding present.

Yeah, I was more pointing out that you'll experience some binding in 4Hi without the benefit of the T3. You'd be surprised how many 5th gen owners we've had who swapped from a 4th gen and were like, "it binds up in 4Hi on turns, my old 4Runner never did that!" I will point out that Toyota's All-Time 4WD is not entirely the same as their AWD set-up, as it is a true 4WD set-up; as opposed to AWD in other Toyotas where they'll use electromagnetic couplers on the rear diffs to disengage the rear axle input shafts similar in concept to the ADD to allow slip and disengage/engage AWD as the vehicle sees fit.

You're right about the ADD, my point about bringing it up was in explaining how Toyota reduces the binding issue and also making anyone who does the swap aware that they may experience a bit of binding on tight turns in 4Hi after swapping in a non-T3 transfer case. I wonder how many people remember the days of manual hubs and such.

Oh man, didn't think about the 4 speed auto being a little shorter than the 5 speed. Don't later year V6 4runners have the 5 speed? I thought the 4 behind the V6 was limited to like 2003/4 and maybe some of 2005?

All V8 4runners have the 5 speed, fortunately for us.

Looking forward to the updates, really interested to see the different challenges with it.

I hadn't thought of that as well now that you mention it. Should be 2005+ V6 4Runners got the A750F, 2003-2004 V6 had the A340. All the V8's had the A750, with the 2003 model being an oddball and using only ATF T-IV (not that it matters in this context.)

I also wonder how critical it is to have the spacer machined round vs. purchasing a slice of round stock? Anyways, I'll go back into my hole now and stop leaking unnecessary information everywhere.

 

[ryanking61]

I hadn't thought of that as well now that you mention it. Should be 2005+ V6 4Runners got the A750F, 2003-2004 V6 had the A340. All the V8's had the A750, with the 2003 model being an oddball and using only ATF T-IV (not that it matters in this context.)

I also wonder how critical it is to have the spacer machined round vs. purchasing a slice of round stock? Anyways, I'll go back into my hole now and stop leaking unnecessary information everywhere.

Yeah I have the 2004 V6 so I have the A340F that is shorter. And what are you referring to with the spacer? You mean the rear driveshaft spacer? I'd assume it requires machining to keep it relatively balanced. Also, it needs to have pretty tight tolerances to match the driveshaft flange bolt pattern as well as the centering ring to line it up to the transfer case flange.

 

[BlackWorksInc]

The reason I was musing about it was because of how much it could throw it off balance. It's one of those things they drill into you when you wrench that you should always match mark the shafts because it'll throw them off balance when you reinstall them. Though honestly I've only ever heard it be an issue if you do that when replacing universals vs. bolting the shaft itself back on.

 

[ryanking61]

The reason I was musing about it was because of how much it could throw it off balance. It's one of those things they drill into you when you wrench that you should always match mark the shafts because it'll throw them off balance when you reinstall them. Though honestly I've only ever heard it be an issue if you do that when replacing universals vs. bolting the shaft itself back on.

Yeah it didn't really throw anything off balance. I'll be able to make my large update posts later tonight with pictures, but the spacer doesn't mess with the driveshaft balancing at all and I didn't have to separate the halves of the driveshaft at all. Drove it all over town and up to 70 and everything was just fine.

 

[xtremewlr]

Yeah it didn't really throw anything off balance. I'll be able to make my large update posts later tonight with pictures, but the spacer doesn't mess with the driveshaft balancing at all and I didn't have to separate the halves of the driveshaft at all. Drove it all over town and up to 70 and everything was just fine.

Good to hear. I was concerned with the spacer. Personally, I went with custom fit driveshafts, front and rear. Had them made at a local driveshaft shop and they did a great job. Ran around $600 for both, so not exactly cheap. Whole project was still right under a grand tho. Cheaper than trying to fix the stock tcase IMO. And more reliable.

 

[ryanking61]

Good to hear. I was concerned with the spacer. Personally, I went with custom fit driveshafts, front and rear. Had them made at a local driveshaft shop and they did a great job. Ran around $600 for both, so not exactly cheap. Whole project was still right under a grand tho. Cheaper than trying to fix the stock tcase IMO. And more reliable.

Yeah doing new driveshafts would be the better option, but more money and I couldn't use my spare driveshaft on wheeling trips if needed anymore.

 

[ryanking61]

New Case Installed! (Mechanical Stuff)

So after spending 10 hours on Friday and 5 hours today, the FJ case is in and works! Took it for a test drive after, got up to highway speeds, put it in 4Lo, and everything is perfect. So now for some photos!

First, here's the center console area before any cutting was done:




Ended up cutting the hole in the floor way too big but we really had no idea what we were working with to start so we just cut away as needed:




So if you look at the pictures so far, we determined that we needed to lose the front left mounting bolt for the transmission shifter housing, which ended up being a good choice cause the shifter hugs it pretty tightly when in 4Lo. But the transmission shifter is mounted plenty sturdily with the other 3 bolts. You can see where we cut out a small section towards the rear at first then started working our way forward as needed. I think I also lost a hole for a clip that held a wiring harness in place but that's not a big deal.

All of the other writeups I've seen on this have been done on V8 trucks with the 5 speed which would have pushed the shifter farther back. Having the 4 speed A340F, my shifter ended up being about 3-4" farther forward, making it really difficult to clear everything. We cut pretty much all the way up to the yaw rate sensor (silver box bolted to the floor).

To cut out the hole, we used a combination of a cheap harbor freight body saw and then a sawzall. It was a slow and painful process but it was better than using a grinder and getting grinding dust everywhere and throwing tons of sparks in the interior.

Just for fun, here's my hand for reference on how large the hole ended up being:




Even though its a large hole, it's nice cause I can take the shifter out of the transfer case without removing the entire case from the vehicle.

So, now on to making the shifter work. This was the most troublesome part of the swap and took my buddy and I about 5 hours of fitting to get it located the way we want. The goal was to get the shifter into the coin pocket w/ the cigarette outlet and avoid trimming any of the center console trim. This was an iterative process and involved probably 10+ test fits of the shifter. The end result was cutting the shifter off and welding in a roughly 3" piece of 1/4" flat bar to get the shifter farther driver and towards the rear. We ended up also having to bend the flat bar up and twist it slightly. There's really no good way to explain this part except for mess with it until you're happy with how it fits.

Another issue we ran into was that the shifter was not long enough, so the shift knob was going to interfere with the edges of the center console trim. To get around this, we got two nuts and a bolt from the store. Welded two nuts together and ran those onto the factory threads of the shifter. Then we welded the head of the bolt to those nuts to get about a 2" extension. Just used an M12x1.25 bolt which is standard threading for shift knobs. I also chose to go with the Marlin turtle shift knob cause I like Marlin

Shifter:




Shift Knob:




Close-up of the Extension:




Before spoiling the cool part of how the shifter fits with the center console trim, let's look at driveshafts. Rear driveshaft turned out to be really simple. I bought a 1.25" driveshaft spacer from 4Crawler Offroad and installed it between the rear driveshaft and the transfer case flange. Installed:




For the front driveshaft, I didn't have to make any modifications. All I did was pull the slip out some more and it bolted right up with plenty of spline engagement left. The front driveshaft changed the length of the dirty section of the driveshaft in the next picture. You can see the line between what was previously exposed and what was previously inside the slip:




Now . . . . shifter fitment!! So I haven't installed all of the center console trim yet, but I'm 99% sure this will work based on the testing method I did. All we did to help place the shifter in the coin pocket was repeatedly place the corresponding trim piece on top of the transmission shifter and line it up as if it were installed. To explain this better visually, here's some pics of the shifter positions.

2WD:




4Hi:




4Lo:




So I call this an absolute win! Shifter is at a really comfortable height as well and doesn't get in the way of access to anything else.

I also wired up the dash lights to work with the new transfer case with the center diff lock light indicating 4Hi and 4Lo to 4Lo. I'll make a post tomorrow with some more details on how that was done.

So everything works but there's still a lot to button up:
- Make sheet metal plate and/or rubber piece to seal the floor as much as possible and reduce noise (chain-drive cases and road noise are super loud)
- Install ADD harness to get the ADD to work
- Wire up an ABS/Traction Control bypass switch
- create method of retaining rear AC (got an idea)

I'm hoping to get all of this done within the next few weeks but school has been super busy so we'll see. Overall I'm so happy it worked and it's cool to be the first (possibly but could be wrong) person with the 4 Speed transmission to install an FJ case.

I couldn't have done this without the help of my friends, so feel free to check out their Instagram pages to see their cool builds. One is a 22RE toyota buggy that runs on propane, and the other is a Jeep Cherokee that is built properly and not hacked like 99% of other Cherokees.

Instagram Handles:
[MENTION=7715]THOMAS[/MENTION]_previti (Toyota Buggy)
@the_green_dumpster (Jeep Cherokee)

Stay tuned for more updates on wiring, sealing the floor, and retaining rear AC!!

 

[xtremewlr]

Nice job! I'd say you did a pretty damn good job with the shift placement. Here's how mine came out. This is in 2WD.

 

[ryanking61]

Nice job! I'd say you did a pretty damn good job with the shift placement. Here's how mine came out. This is in 2WD.

Nice! What shift boot did you use? I still gotta figure that out as well. How'd you attach the boot to the center console trim?

 

[xtremewlr]

Nice! What shift boot did you use? I still gotta figure that out as well. How'd you attach the boot to the center console trim?

Just a fake leather cheapy I found at Autozone. There's enough plastic hanging down from the opening on that top bezel to drill some holes in and I used zip ties to secure the boot around it. Just cut small slits in the bottom of the boot and ran black zip ties thru the hole I drilled and the boot. Worked pretty good that way and I can still use the boot to hold various things if I don't need to use the shifter.

 

[Tomm-]

Ended up cutting the hole in the floor way too big but we really had no idea what we were working with to start so we just cut away as needed:

I can't imagine trying to tackle this with the 4spd trans and no body lift. I feel like the 1.5" body lift you have was absolutely necessary. I've seen it as helpful but not absolutely necessary for the 5spd trans - could be wrong.

 

[ryanking61]

I can't imagine trying to tackle this with the 4spd trans and no body lift. I feel like the 1.5" body lift you have was absolutely necessary. I've seen it as helpful but not absolutely necessary for the 5spd trans - could be wrong.

Yeah for the 4 speed I would agree that it is essential to have the body lift. To be honest, the 1.5" was still tight. Really glad I just happened to have the body lift already.

 

[Tomm-]

Yeah for the 4 speed I would agree that it is essential to have the body lift. To be honest, the 1.5" was still tight. Really glad I just happened to have the body lift already.

Well either way you made it look easy. Good job!

 

[xtremewlr]

I can't imagine trying to tackle this with the 4spd trans and no body lift. I feel like the 1.5" body lift you have was absolutely necessary. I've seen it as helpful but not absolutely necessary for the 5spd trans - could be wrong.

Yeah for the 4 speed I would agree that it is essential to have the body lift. To be honest, the 1.5" was still tight. Really glad I just happened to have the body lift already.

I did a 1" body lift for mine with the A750. A little tight but I wasn't willing to go any higher. It definitely helped with the whole install tho!

 

[mysticz]

Any final pics or updates? :jump: