How-to guide for converting your 2007-2013 Tundra to Full Time AWD capability

awd tundra sounds like a ball... i was thinking about it for my first gen.

 

The '01 Tacoma in your signature sounds like a sick build sir!
You race it or is it more of an off-road warrior?

 

The 01 will be more of a street queen. It will likely be a regular of the drag strip whenever I get it done.
Tundra has taken over the offroad warrior side of things (albeit it’s kinda pretty and I don’t want to completely trash the fresh paint! Lol.)

 

This gentleman shows how the standard Tundra transfer case differs from the Sequoia transfer case, although in his example he's using one from an AWD 4Runner.

 

Sooooo, what would I need in order to do this to a 2wd Tundra? I’d guess it’d be easier for a 2WD 14+ since it doesn’t have the T-Case. Just my uneducated guess

 

@ViktorG ,
Assuming I also take out the 2wd/4wd selector controls, 4wd ecu, wiring harness, and front wheel drive hardware (shafts, diff, etc) from a donor, can the AWD via a sequoia J3FA xfer case be done on a stock 2wd tundra with the same level of success you have had?

 

It would be exceedingly difficult to do this conversion on a 2014+ since it uses a completely different transfer case setup and wiring.

 

It is possible, but it would need more parts than you listed. I am helping a client in Europe with the 2WD to AWD conversion right now, but it is not completed yet.

 

Nice writeup, thanks for sharing .

 

Hi Viktor, any updates on the conversion you mentioned here fro your client in Europe?

 

That project stalled as far as I can tell, I haven't had any updates from the guy in a while.

 

Can this be done with a 2007 Tundra??..Any idea of the approximate cost??...Thank you

 

Hi ViktorG, I just created an account after getting "hooked in the mouth" on this AWD conversion. I bought my "07 in "08 with 4,200 miles and it's right at 333,000 miles now and still going strong. I've ALWAYS wished the truck could be AWD and today, I bought the transfer case from a 2010 5.7 Sequoia. Can you be more specific on the ECU I need and where it is located? Last, is there any special wiring harness change I need to be aware of? I plan to get the correct center diff lock switch for the dash and do an LED indicator of some sort rather than swapping the instrument cluster. I'll keep you posted on progress. I've kept good care of the Tundra and I plan to run it well in excess of 500K miles. It runs and drives just like when I bought it, no joke. I should have the AWD transfer next week and I appreciate the help!!

 

If you have access to the Sequoia, or the place you purchased the t-case from, see if you can get the ECU from that vehicle. It's mounted on the interior of the vehicle up next to the glove box, kind of on the opposite side of the V8 emblem on the exterior. I can't recall if the entire glove box needs to come out to get to it, but I'm sure it would make it easier. There are two connectors on the bottom and one 10mm bolt securing it to the body. The connectors will be the same on both ECUs. I'd guess that dimensionally it's 5x5 inches.

And you have to tag @ViktorG in order for him to see this.

 

Thank you for that! I bought the transfer case off of Ebay for $750 w/shipping and I found the ECU from the same vehicle for $125 so I nabbed it. They also have the dash switch and are going to offer it with 6" of the wiring harness with the plug, which I'm assuming is the proper thing to do. Should I ask for anything else from the donor vehicle? The help is much appreciated and I'll post how things go on the swap.

I'm not sure how to tag people, but I'm going to take a guess: @ViktorG @Wynnded

 

Unless you wanted the gauge cluster as well and the price was right, nothing come to mind. A couple notes on the clusters though, I'd avoid the ones that have the indicators for the rear air suspension. There may be an indicator that shows a small red steering wheel that you probably would want to deal with and there are two ways to do that, and of course there's the indicated mileage on the odometer to correct if that's an issue. If you're not interested in the cluster, then the details are moot.

 

@Wynnded @ViktorG , I received the ECU from the donor 2010 Sequoia today and I’m not clear on the 40 pin connector I’ll need to be wiring into pins 12 and 14. I thought I’d see a 40 pin terminal connection on this ECU, but I’m missing something here. Please let me know where the 40 pin connector is on the truck and whether I’ve bought the correct computer control unit. Sorry for my confusion, but help clear my fog and there’ll be another AWD Tundra on the road.

The Sequoia transfer case is still in transit. Maybe once I get it I’ll be able to better wrap my head around this swap.

Once I know I’ve got my ducks in a row, I’ll pull the rear drive shaft and run front wheel drive (in 4WD) while I get the rear drive shaft shortened 1-1/4” in Fort Wayne. Once I get it back, the scalpels come out!

The help is much appreciated!

Steve

 

That's an engine/transmission ECU. You need a 4WD ECU which is much smaller. Here's a picture of the one I removed from my truck, the Sequoia one will be the same but the part numbers will be different.

 

@Wynnded , thank you for that. I’ll set out to get this from the donor vehicle right away. Any value in me keeping this engine/transmission ECU? Is it even compatible with my ‘07 Tundra?

 

I do not know for certain that you could use the Sequoia engine/transmission ECU for any purpose, I would be quite surprised if you could. I've not read of anyone doing so, and nor can I think of any advantage that would be gained.

 

@Wynnded and @ViktorG, So I pretty much have my ducks in a row for making the t-case swap this weekend. The rear drive shaft is at American Driveline in Dayton, OH where they are shortening the steel tube by 1-1/4" and balancing ($140) and replacing the three u-joints and center bearing ($30 for all, which is an extreme bargain in my book!) with OEM Toyota parts I supplied. I nabbed a front drive shaft on eBay from a 2017 Sequoia with 44k miles for $85, free shipping, didn't have to think about that one! The 4X4 ECU and diff lock switch should be here tomorrow from the donor Sequoia, both with the plugs and section of wiring harness. Transmission jack and Lucas 75w90 gear oil on hand as well.

I found small red LED blinking lights on Amazon

$9 EDGELEC 100pcs 5mm Red Blinking Diffused LED Diodes 1.5Hz Flash (Single Color Flashing) Round Lens 29mm Lead DC 2V Blink Bulb Lamp Light Emitting Diode +100pcs Resistors 470ohm for DC 6-12V Included

https://www.amazon.com/dp/B077XCM7QZ?ref=ppx_yo2_dt_b_product_details and I'm going to see if I can add one in behind the push button for my indicator. If it works, I'll post details on that.

I wanted to pre-wire the diff lock switch and found that pin 12 is open on my harness. I'll dissect the donor plug when I get it to figure out how to remove the terminals and add in the wires on pins 12 and 14 without cutting and splicing wires ahead of the swap. I added fog lights some time ago (my truck did not have them) and I added in a correct OEMish dash switch, so I'll grab my power, illumination and ground from it. My only question is am I sending a positive or ground signal to pin 12?

As soon as I get an answer on this I'll wire in the diff lock switch and should be all ready for the swap. I don't think there's any need for me to chronicle my swap start to finish in any detail on this thread, but let me know if you think I should and I will.

Thank you again for the help and all of your posts on this swap including TundraTalk, it is much appreciated!!

Steve

 

Well, as promised, a follow up after the conversion to the Sequoia transfer case. My son and I made the swap last Saturday and went fairly well. My older brother supplied a semi transmission jack and several blocks of cribbing that we drove the truck up on for some extra clearance under the truck. I might miss a few details as I recap but I'll definitely hit the main highlights.

I pulled the rear drive shaft the week prior (drove front wheel drive for the week) and had it shortened 1-1/4", replaced the three u-joints, center bearing and rebalanced, all for $170 with me supplying Toyota OEM components. I found a front 2017 Sequoia drive shaft with 44K miles on eBay for $85 with shipping, so that was covered.

The first thing was to unbolt the isolation mounts from the transfer case leaving them mounted to the cross member and support the weight from the cross member with a bottle jack and large block of wood under the transmission. We next removed the cross member with some difficulty as the four bolts had rust jacking within the cross member (15 years in the rust belt). With the cross member out, we drained the fluid from the transfer case, removed the front drive shaft, disconnected two breather lines and three clips from the wiring harness and liberated the two clips from the transfer case that anchors the wiring harness. We secured the t-case to the jack via two ratchet straps, then removed the five rear facing bolts and three front facing bolts and removed the t-case.

Reverse procedure to install the Sequoia t-case, filling the fluid prior to reinstalling the cross member. Carefully note the orientation of the center bearing on the rear drive shaft. I installed it unaware 180° off and thought there was a problem with the balancing on the drive shaft. The shop that did the work invited me to bring the truck in for them to look at it. After about an hour and two test drives, they found the problem and fixed it, no charge. I did however show them my gratitude for correcting my error $$!

As far as the electrical connections with the Sequoia ECU swap, ViktorG has it fairly clear in his write up on Tundra Talk. The short of it is, is that pin 12 is looking for a negative (ground) signal from the diff lock switch, not positive. Pin 12 on my wiring harness was open so I added in the correct pin terminal from the donor ECU wiring harness. Anyone needing any of these can contact me and I'll send you what you need.

I left the original wire on pin 14 out and wired in a new wire for the diff lock indicator light (this is sending out a positive signal as noted by ViktorG). As it turns out, the truck would not engage 4WD, noting that the transfer case was indeed shifting, but the front diff was not. I suspected the original wire to pin 14 was needed. I added it back in, splicing in another wire for the indicator and everything worked fine. I believe the t-case or ECU is sending a signal to pin 14 when it engages 4WD which then gives the OK to initiate the front differential engagement.

We had a significant winter storm this week and traveling from Cincinnati to work and to home was pretty dang sweet in AWD!! Many thanks to @ViktorG and @Wynnded for their write ups and answers to my questions. I realize the pre 2014 Tundras are getting some age and maybe this swap is less common now, but if any of you reading this are considering the swap, it is well worth it. I've mentioned earlier that my '07 had 4,200 miles when I bought it in '08 and today has 335K miles, but it is far from it's expiration date and I plan to run it well in excess of 500K. The truck still looks and runs quite well, is exceptionally reliable and I have no intention to initiate another round of truck payments to replace it.

Thank you to all that have contributed to this thread, it is much appreciated and I invite any questions or comments.

I'll probably get asked, so:

2010 Sequoia t-case 132K miles $750 with free shipping from eBay

ECU, diff lock switch, both with plugs from the donor vehicle $125

Front Sequoia drive shaft $85 with free shipping from eBay

Rear drive shaft work $170 at American Driveline in Dayton, OH

All in all, it was a great investment!

I'll probably list the original Tundra t-case on eBay to redeem some of the cost.

Steve

 

Man i fell down this rabbit hole today. One of my biggest gripes is the 4wd on snow/ice. Having to lock in 4hi just to get out of the neighborhood and then 2wd to make turns to the main road. Think I'm gonna have to start acquiring parts for this. Maybe make the drive up to Calgary and bribe @ViktorG with $$ and beers.

 

Did that conversion ever get done? I’d love to swap mine. Pretty sure it would be cheaper than trying to upgrade to a comparable 4wd which I would still want to do the AWD mod to anyway.

 

The guy in question paid me for some consulting and information and I have not heard from him since.
He had a complete crashed 4x4 Tundra that he could use as a donor to do a complete swap to a 2WD, so I am sure it would be possible with enough time and money.

 

@BigSkyTaco , you might consider this on EBay: 165468726622. It is as low as I’ve seen lately with free shipping plus make offer. I would suggest asking for the 4X4 ECM (not ENGINE ECM), differential lock switch (dash mounted) and optionally the front drive shaft from the Sequoia. It does have higher mileage, but that doesn’t scare me with Toyotas.

 

Good looking out! I have a alert set for ebay, but this one did not pop up. I just called and left a message.

 

@BigSkyTaco Search for 5.7 Sequoia Transfer on Ebay. Weeds out all the others and finds what you are looking for.

 

So can I use the stock front differential also ? I have a 2wd tundra and very interested in doing this can I use the awd and still turn on the street?