FrenchTacos 2003 4WD Conversion

BACKGROUND INFO
I've owned bmws my whole life. My first of many was a 1971 2002 in high school.
After a while I figured that the maintenance was too much as a student and that it didn't do what I wanted when I went to the outdoors I love so much.
So... I bought a tacoma because I've always liked em.
The 2wd has been great but getting stuck in the snow once pissed me off enough to wanna take on a sweet project.

ACTUAL CONVERSION INFO

Mechanically the swap is not too complicated.
A lot of people want a full write up/tutorial but that would take insane amounts of time.
What really matters are the key components you buy.

• 4wd hubs and CV's
  • 3rd Gen 4Runner and all 1st Gen Tacoma's will fit

• Front differential
  • 3rd Gen 4Runner and all 1st Gen Tacoma's will fit (make sure ratio matches rear differential.)
• Front Drive shaft
  • For sure all first gen Taco front shafts will work for automatic transmissions. I'm not sure if length is different for manual. Think 4runner 3rd gen might also work. They are not hard to find.
• Transfer Case
  • 3rd Gen 4Runner and all 1st Gen Tacoma's will fit. ( Two types. J-shift and push button) Read further for more info
• 4wd transmission or 4WD shaft and Mount to modify
  • For automatic the 3rd Gen 4Runner and all 1st Gen Tacoma's will fit. Make sure you get the a340f. That is the 4x4 tranny. Or just get the output shaft to put into your 2wd tranny.
• Rear Driveshaft
  • Rear shaft is 2 pieces. The front half of the rear shaft from any first gen taco will fit.

With enough research you will see that most parts are compatible. That is the hardest part.

But I don't know how to install any of this?

What this swap is once you have the parts is simply mounting them.
Get a service manual, or haynes manual and look up INDIVIDUAL instructions.
Look up how to remove hubs, look up how to remove transmission, how to remove drive shaft etc. These are all procedures that are found on youtube or how to manuals.

My plan

I'm doing the build in two parts. One part is the front differential, the 4wd hubs with ABS and the cvs.

The next part will be the transmission,transfer case and drive shaft work.

Spindles And Hubs
3rd gen 4runner/first gen taco spindles and hubs are compatible.

I started out with 97 4 runner non ABS spindles. The spindles are the exact same other than that the hole for the ABS sensor is not machined out.
Here i circled where the ABS sensor port is not machined.

The spindles in my truck have ABS port.
As much as I hate the ABS in this car I decided to keep it. So to keep ABS I had to reuse my own spindles because they have the ABS port machined.

SAVE MONEY
(If you want to save money and have a 4wd non abs spindle/hub set up. Bolt it directly into the car and ditch ABS)

I pressed out the 4wd hubs from the non ABS spindles.
Then I pressed the 2wd hubs out of my ABS spindles.
Took the 4wd hubs and pressed them into my ABS spindles.
When you push the hubs out of a spindle assembly the bearings break.

KEY NOTE:
When removing hubs you will need new: Bearings, inner seal,outer seal and your snap ring if it was damaged upon removal.
This was an unexpected cost. I did not realize the bearings would break. The two timken bearings and seals cost me about 180$. That is "cheap" for the parts but I did not plan for this in the budget.

BE CAREFUL!!

Work was going very smoothly until I screwed up 150$ worth of bearings.
I have never done bearings before but I have a nice Enerpac hydraulic press at work so decided to try it.
Pressing out the 2wd hubs and bearings was relatively easy. At that point I was going to have a shop press the new bearings in but I figured what the hell cant be that hard.
I used an old bearing to press the new ones in and they went in perfectly.

Now... A very big mistake that I made was during the Hub pressing.
The hub makes contact with the inner part of the bearing once it is pressed in all the way. That makes it so that the inner part of the bearing will get pushed through the back if you do not support it. Well, I supported the steering knuckle on the back side and not the inner part of the bearing so... One tad too much on the hydraulic press and crack. The hub forced the bearing down too much and fucked it up.
I did not take many pictures of the front hub and spindle work but here is a picture of the deformed bearing due to improper support.

Here is another picture of the busted bearing. IGNORE HOW ITS SITTING ON THE HUB. I just propped it on there to take a picture.


This set me back quite some time due to having to wait for the new bearings to ship.
I HIGHLY RECOMMEND HAVING A SHOP DO THIS. IF YOU CAN PRESS THEM OUT DO IT BUT HAVE SOMEONE PRESS EVERYTHING IN. ESPECIALLY BECAUSE THIS LOCKING RING FOR MANUAL HUBS NEEDS TO BE TORQUED AT 205 FT BLS WITH SPECIAL TOOL.


Here is a picture of my manual hubs taken apart. I wanted to clean them and understand how they work.

This guy here explains how to put them back together. It can be quite tricky.
https://www.youtube.com/embed/W78RkF1mUOE

I also do not show the turning handle taken apart. If you have a hard time turning the handle it is simply the o-ring in the handle part. It is held by a big snap ring. If the O-ring expands (wet or due to age) it will make it really hard to turn the handle due to FRICTION. The mechanism itself should not have any resistance when turning.
Here is my little video of me making sure I reassembled the mechanism correctly.


Differential
4.10 to match the stock 4.10 electric locker in the rear.
Once again 3rd gen 4runner diff will work as well as first gen taco diffs.
FOr compatibility you gotta worry about the ratio matching the rear diff ratio.
Also, if you are using manual hubs you will need a NON add differential tube. You will also need manual hub CV's they are different.
Here is some general info on Non ADD and ADD differentials. ADD* (automatic disconnecting differential)

I got mine from a dude that parts out 4runners on Craigslist. Here in the bay area Tacoma parts are incredibly expensive. 4runner parts seem to be cheaper.
The differential came with the ADD tube.

I wanted manual locking hubs so I pulled the ADD tube out.

Then I pulled the intermediate shaft out of the differential. It's used with the ADD tube. Don't need it.

Here is the non ADD tube and diff.

Here it is mounted.




Transmission and Transfer Case

The 4wd Tacoma transmission is the A340F. The 2wd tranny is the A340E.
The main difference is the output shaft. The output shaft of the A340F is shorter than the A340E. You also need the 4wd transmission tail housing AND a 4x4 transmission mount. It is different than the 2wd tail housing and 2wd mount.
I believe the oil pans might be different but I didn't modify any of that.
Since my current 2wd tranmission has a good history and 130k thousand miles I decided to keep it. Also by having a professional swap the shafts versus buying a random 4wd transmission I would receive feedback on how my transmission looks. He said it looked great no repairs needed.

Here is the 2wd tail housing


This is the 2wd tail housing when we pulled the transmission out.

This is the 4wd tail housing without the transfer case mounted before install.

This is the 4wd tail housing again with the transfer case attached and no transmission. Allows you to mate the transfer case to tranny.


Luckily I found an A340F output shaft on Ebay for cheap in order to convert my 2wd tranny to 4wd.
4wd shaft

2wd shaft


Now I did not want to take the transmission apart so a good tranny shop quoted me 250$ to swap the shafts. I would bring the transmission to them.
Good deal if you ask me.

Here is the best part. I ran into a friend of a friend who works at a transmission shop. He talked to his boss to see if they would strictly take the transmission work. Instead, he offered to help me take the transmission out during off hours, do the tranny work on shop time and reinstall on off hours. He has a lot of free time after work and he thought it was a cool project.
Hell yeah!!
So my new connection was enthusiastic about helping me complete this project.
We took the tranny out in an hour. That included shooting the shit so relatively easy with a lift and power tools... (Would have taken much longer on my back in the garage but its nothing complicated. Just tedious nature of the work due to laying on floor)

Next day he picked it apart at work. This is the one part of the swap I have no knowledge about. I was not there to take the transmission apart. He did mention how easy it was and offered to take it apart again and reinstall just so I could see how its done. Pictures are random no order.









Mind you I was not charged. The boss was very friendly and my buddy did most the transmission work on his off time.
Since I did not have to pay anything and got to work on a lift I made sure to appropriately compensate my buddy.

Transfer Case
This is also fairly simple. The 3rd gen 4runner cases will fit and so will all first gen Taco cases.I'm unsure how the electronic transfer case works with the push button 4wd. I do know they will mount up.
The transfer case from manual vehicles have longer input shafts but I do believe they will fit. I think he talks about it in his transfer case replacement.

Speed Sensor.
For your cars speedometer to work you need a working speed sensor. For the 2wd transmission the speed sensor is in the tail housing. The 4wd tail housing does not have a hole for the speed sensor. The hole is in the transfer case. The 2wd speed sensor is not reusable as it will not fit in the transfer case.
2wd speed sensor looks like this. I do not have a picture of the one I got from transfer case.


Since the speed sensor is now located further back at the transfer case you need to extend the wires on the factory harness that have the VSS plug. Just splice the wires, add some length, solder them and heat shrink. Done.


Dont ask me what year but some transfer cases have mechanical speed sensors. If you buy the transfer case and see that your speed sensor does not have an electrical plug connection it is a cable driven sensor. No big deal. Buy an adapter here.

https://www.marlincrawler.com/transfer-case/parts-upgrade/tc-hilux/vehicle-speed-sensor-mci

I think there is a cheaper one somewhere but that's just to show you the idea.
My transfer case came with no speed sensor. It had a plug. Mystery mystery.
Well some of the 4runners read the speed using the ABS sensors. So the transfer case VSS hole was plugged.
The speed sensor has a plastic gear on it. The number of teeth will dictate how accurate your speedometer is. I think some have different gears because of wheel and tire size? I have no fricking idea. But the main point is if you plug it in and your speed doesnt seem right. Just go to the dealer and see what other gears they have.
I got mine from a place called Toy Connection here. I was in there shop and saw a transfer case laying around. Had them pop it out and charged me 85$. It works.

I used a J shift manual style since I knew it would bolt right up and require no wiring.
I bought it off Craigslist from a guy parting 4 runners.

I left the position sensors on the Tcase unconnected since my harness doesn't have plugs for it. I believe I could make my own lights if the cable is positive and ground. Have each position flash a different light. I have not gotten to that yet and its not really necessary.

The transfer case was making a loud chain noise when I spun it by hand so I pulled it apart to look inside and at a quick glance it all looked fine so we resealed and mounted it. (It is currently making noise while driving. Thinking about replacing)
Here it is mounted in the car. It went up attached to the transmission as one package.


For the shifter to fit in the tunnel you must take out the 2wd shifter plate and cut it where the X is.



DRIVE SHAFTS

The front drive shaft from transfer case to front diff can be taken off any First Gen Taco or 3rd Gen 4Runner.
The rear driveshaft is 2 pieces. You need to replace the front half of the drive shaft.
This can be pulled from any first gen extended cab. (unsure about single cab)
Or you can have it cut and welded. This is more $ and downtime.

 

UPDATE:
Swap is complete.
Need to go test the 4wd somewhere.

 

Dang...that was fast, haha. Most people that post about doing a 4wd conversion take weeks, months or even years to collect all the parts and put it all together. Congrats on the conversion, let us know how it works out!

 

Haha dont worry man I've been collecting while going to school for about 7 months. Most of it was down time because I was studying but I had to finish this during the summer before school picks back up.

 

UPDATE:
I've been driving the car for a week now with transfer case noise but I'm starting to think its really not normal.
The drive there in traffic was about 4-5 hours. My transfer case kept ticking. Going uphill it was a little louder. Same with going downhill foot off the gas. I have a sound video I will post. I do think its chain noise but I dont think its normal.
Also, when I put the car in Neutral I can shift from 2Hi to 4hi to neutral. Then sometimes it wont let me shift into 4lo. It will buzz when I try to shift. I have to shut the car off and put it into gear. Then turn car back on.
I thin overall the transfer case has issues. I might look into a different one.

Alsom there is a new clunking noise on driver front left. When I go over a pump at 10-25 it makes a metal clank.
I checked all bolts and everything seems tight. It also clunks when I accelerate into a turn from a dead stop. EX: Peeling out of a driveway to pick up speed merging on street.

Not sure what that could be.
I didn't push the truck too much because I didn't wanna be stranded 3+ hours from my house but I need to zone in on the metal clank noise and run the transfer case or find a new one.



Me putting it in 4wd for the first time trying to go up a huge mound of gravel.
I didn't take many pics because the phone gives no depth perception and makes everywhere I go look flat.

 

Here is a video of the sound my transfer case makes.
It definitely sounds like the chain. But is it normal?
https://www.youtube.com/embed/Y5ODB-UwKpA
https://youtu.be/hWgLJPnDtus

 

Mega subd. Video doesn't work, try posting to YouTube then here.

 

Video worked for me when I clicked on it, it took me to photobucket and played from there.

I don't hear anything though other than the sound of the motor in the background, sounds normal to me?

 

Listen past the road noise. Its faint. Its like a shshshshshshshshsh noise haha.
Like a chain noise. Hard to get a good sound recording due to the other noises.

 

Well done

 

Thanks.
Trying to make it as easy as possible for others

 

I am working on a similar swap currently. I don't have any issues with my transfer case, but the grinding when shifting from 4hi to 4lo and vice versa is something I also have. Make the shift quickly, don't pause in neutral on the transfer case shifter, and you will avoid the grinding.

 

Wow awesome first post. Very helpful!

 

Thanks!

 

How hard/expensive would this be for a 17yr old kid working at McDonalds part time with barely any knowledge about trucks to do?

 

Hey man. Good question.
It's tough for me to answer because I was 17 not long ago (7 years ago) which is when I started working on cars. To do this conversion you must have a few years of experience. It is a big project to take on with very little experience.
I really hate to give my personal opinion on things because I think you should do what you want. But I will give you my view on it.

At 17 year olds working at mc donalds I would recommend to modify your truck in small ways. The way to get better at working on cars is to gain confidence. That starts with doing small jobs. Brake job, suspension, miscellaneous mods. Going straight into a conversion like this can be overwhelming.

I dont want to discourage you but I want to be realistic so I will ask you a few questions.

Why do you want to convert your truck?
Do you have garage/driveway space to work on it?
Do you need a daily driver to live life (get to work etc)
Are you dead set on driving a 4x4 tacoma ? (Lots of other cheaper 4x4 vehicles you can buy)
Are you wiling to spend 1500 on this? (Budgets vary but I feel like this is a safe budget)

IT is a pretty big project at your age. I would recommend slowly learning how to work on cars first. That is what I did.

 

Ive been slowly testing the waters in my mechanical knowledge doing misc. things such as oil changes, brake jobs and other things here and there. I would be doing the swap because my dad and i both enjoy working on my truck and are always looking for a project to do on it, and also use the 4WD to explore some less traveled trails. Luckily i have space to store it for a few days while we work on it. I have other vehicles at my disposal so its not a big deal if my truck is out of action for a little bit. I dont really want to sell my truck as ive put a lot of money into upgrades, im not dead set on 4x4 but i think it would be cool to have in case i need it (ive learned the hard way where 4x4 is necessary). 1500 is a pretty normal number. Ive spent about that much on my truck a few times already, just takes some time to save up. Like i said im always looking for things to do on it, but unfortunately everything is working properly on it. From what ive seen, converting a prerunner to 4WD is pretty much plug and play, just bolt things in a do a few small modifications to the truck but im not 100% sure

 

Your dad is excited (supporting you)
You have work space
You have another mode of transportation
You seem excited about the learning process (working on it and understanding)
You can get 1500 over time

With all that I would encourage you to do the conversion. The hard part of the conversion is not the wrenching. The wrenching is intensive and you must have patience and knowledge but it is "plug and play".
It is the collection of parts thats consuming and "difficult". You need to gather the right parts. Once you start modifying your car you will be dead in the water if you are missing ANY LITTLE PART. So you must spend a lot of time to make sure you have every nut and bolt before you work on the car. It will make it so that you can finish the conversion in a few days.

What would make your life a lot easier would be to find a wrecked 4x4 tacoma. Or someone willing to part out the whole 4x4 system at once!! You would be surprised at how many things you need when you buy parts here and there. (Hardware,small missing pieces etc).
If you cannot find a whole assembly then start piecing all the parts together. It took me about 6-7 months because I was in school. I had the money but I didn't have the time to consitently check craigslist and the forums.
Start collecting.

 

Yep ill have to keep an eye on local junkyards and Craigslist postings. have you made any progress with your transfer case?

 

Yup, gathering the parts will take a long time unless you find a package deal so good luck.
I'm just going to run the transfer case as is. I'll swap it out once it starts making crazy noise or blows up. For now I'm keeping it. I'm keeping my eye out for a cheap one though to have in case I need to swap. Its not too hard to do.
I'm also having a clunking noise. That I actually think does not have to do with the swap. If you lift your car with the wheels off the ground, move the wheel side to side and hear a clunk then the rack bushings are most likely bad. My rack is moving back and forth like crazy because the bushings are shot.
Im getting new bushings hopefully clunk will go away. *This is just general info for anyone that might have some random noise in the front