DriveTrain
At a glance
My '99 Toyota 4Runner came stock with:
3.4L V6 Engine
4 speed Automatic transmission
2 speed chain transfer case
Front drive shaft had only two u-joints, no CV joints
Rear drive shaft had 1 CV joints
Stock tires were P265/70R16
Front/Rear Gears: 4.30:1
Rear Factory Locker
Manufactured 3/99
GVWR:
5250LBS
GAWR:
FRT 2650 with P265/70R16 tires at 32PSI cold
RR 3000 with P265/70R16
tires at 32PSI.
VZN185L-GKPZKA
C/TR K79/LF45
A/TM A04A/A340F
Engine
To maintain the Toyota reliability, I didn't want to mess with the engine too much.
Due to the Solid Axle Swap, I did change some items that pertain to the differential. The Oil Pan is now a T100 oil pan, with the sump in the rear. This is to allow the pan hard bar movement uptowards the engine. I also installed a new Dip Stick tube and pickup. This wasn't major surgery, but necessary to clearance the new D44 axle.
I have installed a Downey Air Intake, part number: 171F1-99C,
'99-04 Air Cleaner w/Chrome tube. This unit has definitely helped with the
aspiration of the engine.
I also have the Pre-Charger wrap. This wrap does help in keeping the filter
cleaner for a longer period of time.
Transmission
Well, the transmission is part of the drivetrain, but I haven't messed with its internals. Why mess with something that works, and very well I might add. Despite being at sever angles, sideways and up and down, it has performed flawlessly. One thing I added to the transmission, was a cooler. There are times when crawling through the hot Moab terrain, transmission fluid can get too hot. In addition to the transmission cooler at the bottom of the radiator, I put an inline cooler up front.
Attached to the A/C radiator is the Transmission cooler. Last year my wife and I went to Moab over the July 4th weekend. Needless to say, it was hot. We crawled through several trails, and never had an issue with the transmission overheating.
Transfer Case
I have the stock Multi-matic 2 speed transfer case that comes with the '99 4Runner limited. This transfer case has a push-button 4WD switch on the side of the transfer case lever that allows 4WD on dry pavement. This is great if the weather is spotty, maybe a little bit of snow in certain sections of the road. This condition can be exercised up to 62mph.
The lever can then be pulled back towards the driver, and shifted into 4-Hi. This condition is good for dirt roads, muddy roads, but should not be used on dry pavement.
The lever can then be pushed to the right, and forward and put into 4-Lo. This action will engage the transfer case into its lowest gear and lock the transfer case so it splits the power 50/50 front and rear. In stock mode, if the Gray wire mod had not been done, this is the only time you can engage the rear locker.
Since the Solid Axle Swap, I have modified the Transfer case mount. I'm using a FROR transfer case mount to hold the transfer case in position. I'm also considering making another mount to use the stock mounting location. This will give a more solid foundation for the transmission and transfercase.
Ok, how about the electronics of this beast you ask. Well, its not too bad after thinking it through and putting some relays into the mix.
First off, lets take a loot at some schematics and get a bearing on what is happening when the transfer case is moving from 2wd to 4wd.
Above are two pages to the 4wd ecu. Open these pages in different windows and reference them as we read along.
Here are the conditions and results of the transfer case:
Condition |
Result |
| Transfer case lever in the H2 position, 4WD button not pushed |
T3 (2-4 Select switch = open) D30 (Detection switch [shift Diff Lock = open]) A10 (ADD Indicator switch = open) 4WD = OFF |
| Transfer case lever in H4F position, 4WD button pushed |
T3(2-4 Select switch = closed) D30 (Detection switch [shift Diff Lock = open]) A10 (ADD Indicator switch = closed) Full time 4WD = ON; Can drive on pavement, Combination meter 4wd indicator - greens tires light up |
Transfer case lever in H4L, 4WD button pushed or not pushed |
T3(2-4 Select switch = open or closed) D30(Detection switch [shift Diff Lock = closed]) A10 (ADD indicator switch = closed) 4WD = ON, H4 for dirt road conditions, Combination meter 4wd indicator - green tires and orange center lights are illuminated |
| Transfer case lever in L4L, 4WD button pushed or not pushed | T3(2-4 Select switch = open or closed) |
And to make it even more confusing, take a good look at this scanned 4WD ECU system outline. I have put a new notes in there to try and help decipher this info:
So what does all that mean, well.....it'll help your troubleshoot what switches should be open or closed. One thing that happens in a SAS (SAC) is that the front diff is removed. This also removes the A10 (Automatic Differential Disconnect Indicator) switch, on page one. When this switch is removed, moving into 4wd doesn't work so well. Sure shifting into Low 4 works, as this is a mechanical operation with the lever. But, H4 and Full time 4WD, no deal. Not to mention, those darn lights will blink at you all day until you get this straightened out and close the loops.
What I found, was when the A10 switch (ADD indicator switch) was open, the 4WD would not work properly. The 4WD system is waiting for the ADD sleeve to slide into position, closing this switch, before it will allow the Four Wheel Drive system to work. There are a couple of vacuum actuated valves (V4 and V5, page two) that control this sleeve and thus, allow this switch to be opened and closed. When the V5 (VSV - 4WD, ADD) valve is energized, the sleeve slides into the 4WD position. When the V4 (VSV - 2WD, ADD) valve is energized, the sleeve slides into the 2WD position. These vacuum valves are controlled via the F7 (4WD ECU). This 4WD ECU detects the 4WD button, and transfer case lever movement, and attempts to enable or disable these valves, and thus the 4WD system works or does not work.
As you can see, a relay is needed to move the A10 (ADD indicator switch) switch to the on position when needed. However, what do you use to switch the relay on and off. Since I don't have the V5 vacuum switch any more, I used the V5 VSV (4WD, ADD) Green wire to energize/de-energize the relay. When I switch into 4wd, the relay is energized and the normally-open relay closes the connection of the A10 switch, or rather it grounds it out. Then the 4WD ECU thinks the front diff is ready for the 4WD, and allows the transfer case to shift into 4wd. Recall, I don't really have an A10 switch, this was removed with the front IFS diff when the SAS was done. But, I still have the wire that comes from the 4WD ECU that is running out to the phantom switch. So, it is this wire in reality that is being left open (when the relay is not energized) and closed when the V5 switch is energized. It all works very well, and very quickly.
Hope this can guide you a little in your endeavors of fixing your 4wd.
Drivelines
The front stock drive line does not have a CV joint on the
top end, near the transfer case. Of course, with IFS, it doesn't really
need one. When I change my front suspension to a Solid Axle, I explained
this lack of a CV to Jesse at High-Angle Driveline. He was quite surprised
to find that there was no stock CV. Because my SAS has coil-overs, the
length of the front links does not change under compression and extension.
The arc of the link changes, but the length 
does not change. With the upper
portion of the links mounted right next to the driveshaft, the arc of the
link and the driveshaft is almost identical. Thus, a long-travel slip-yoke
would not be needed. So, Jesse used my existing
driveline, and put on a Tacoma CV joint on the top end of the driveshaft.
Leaf spring front ends with lots of travel
will need long travel slip-yokes, due to two different points of reference
when suspension moves. Leaf springs can have the shackles in front of the
springs or in the rear of the springs. Having them in front gives a harsher
ride, can promote Shackle inversion if the shackles are too short, or if
the suspension was setup incorrectly can bend leafs and gives a bad approach
angle. Prying an inverted shackle from the frame can be dangerous and is
not good for the springs under repeating circumstances.
Having them in the rear gives a much smoother ride. Some people have said
that having the shackles up front will allow a hard-core rig to climb better,
however most of us use our rigs as daily drivers and then hit the trails
on the weekends. This is why the Shackle reversal kits are so popular. Either
way, shackles allow the springs to compress and extend from a pivot point.
This pivot point on a leaf spring is different than the pivot point on the
drive shaft. So, if you are planning on lots of travel for your front leaf
spring vehicle, plan on a long travel slip yoke as well.
Here is some good reading information about leaf springs, axle movement and shackle reversal kits.
http://www.quadratec.com/jeep_knowledgebase/article-93.htm
http://www.4x4wire.com/jeep/reviews/ftssr01/
The Rear drive shaft is a Tom Woods job. When I put on leaf springs, I moved the rear axle back about 1.5". So, I needed to increase my drive shaft this amount as well. I sent my drive shaft to Tom and he reworked it, making the wall .120 thick, and did a superb job on balancing it. With my commuter tires on (much smoother ride), I get no vibration, even up to 85mph. Really a great job.
Exhaust
When I did the rear leaf spring conversion, I changed out my exhaust to a Aero Exhaust. I have the 2525 Turbine. I like the mellow sound of this exhaust, and it seems to have improved my power a bit.
Gears
The original gears were 4.30. These were adequate for the
stock P275/70R16 tires. When I installed and ARB unit in my front IFS diff,
I changed out my gears. Since I was already running ~33" tires, and I knew
one day I would run 35" tires, I opted to move to 4.88 gears. So, I had
my rear and front setup with 4.88 gears. Later on, when I changed my front
suspension to a Solid Axle, I put in 4.88 gears to match the rear. Now that
I have 35" commuter tires and 37" trail tires, I'm right were I need to be.
That's planning ahead.
Click on the image at left to see an exploded diagram of what
parts go on a 3rd Gen Rear Locking Differential.
However, in my planning, I visited a shop in colorado that did a sorry job of setting up my gears. I didn't discover this until a little bit later when I started putting rear leaf springs on my rear axle. When I pulled my axle apart and pulled the third member out, I was surprised to see that some parts were missing. The pictures below show that the Lock Plates for the ring bolts were missing, and the Adjusting Nut Lock was beat into place.
When the Adjusting Nut Lock bolts were pulled out, obviously a gorilla in Colorado was working on my differential. I think he must have lost the torque wrench when it came time to put my diff together.
I took this third member to my local dealership where I know the Master Mechanic there. He got the correct parts and fixed up my diff with a good pattern. He replaced the missing Lock Plates, and the damage bolts. I had to pay more, but I guess its true, "you get what you pay for". In this case though, I had to pay some sorry place in Colorado for a bad job, and then pay somebody else to do it right.
The following information was gathered using a calculator on 4Crawler's site: http://www.4crawler.com/4x4/4LoCalc.shtml#FindRPM
The vehicle: 1999 4Runner Limited w/4spd Auto 4x4 w/Tow package
Given the constants:
Speed: 70MPH
Transmission Ratio: .71 (Overdrive)
Transfer case ratio: 1
Stock
Axle Ratio: 4.30
Tire Diameter: P265/70R16 (30.6x10.4x16)
RPM = 2343.6
Modified to crawler status
Axle Ratio: 4.88
Tire Diameter: 37" MT/R
RPM = 2202.5
Modified to commuter status
Axle Ratio: 4.88
Tire Diameter: 35" BFG/AT
RPM = 2328.3
From stock to rock crawler there is a 6.5% change, not too bad, when moving
from a 30.6" tire to a 37" tire.
From stock to commuter, there is a less than 1% difference in RPMs. This
is a very nice change for 35" tires.
When I cruise to work the speed limit is 55mph. So, as I flow with the traffic,
I'm almost always below 2k rpm. This of course is good for my gas mileage.
Manual Lockouts
Currently, I use Warn Premium hubs on the front of my Solid Axle. I also run Warn Hub Fuses to prevent costly damage to U-joints or Ring Gears. Because these are the weak link, I have a spare Warn Hub, loaded with another fuse sitting in my spare parts bag. Its easier to change out a hub, than a broken U-joint. And, its much cheaper.
For the rear setup, because I have a Full Floater axle, I chose not to go with selectable lockout hubs, but instead chose a flange from FROR.
In my opinion, Manual Hubs are a good thing. If you have an IFS setup and you snap an outboard joint, you can pull that outboard joint, seal up the bearings on the inside and continue on. Back in 2003 I broke the passenger side axle on Whale Rock. Because I had Manual Lockouts, I pulled the outboard joint and broken shaft and then put a plastic grease can cap to cover the bearings. I was able to zip tie the cap into place to keep any dirt from getting into the bearings. Five minutes after I performed this trail repair, a hail-storm and lots of rain came pouring down. I was able to drive out of Chinaman's Gulch in 3-wheel drive. I kept the front locker engage to provide power to the driver side wheel, and the locked differential in the rear gave power to both rear wheels.
IF I didn't have manual lockout hubs, or full-time hubs, it would be a little different. The outboard joint not only transfer torque to the hub, and ultimately to the tire, but is also serves to hold the pressed-hub together. Had I broke an axle shaft, I would have to pull out the outboard joint out, then break apart the shaft from the cage in the outboard joint. Then put the outboard joint back into the hub to hold the pressed hub together. A little more work
Here are a few informational pictures of the manual hubs that I used when I had my '99 IFS Setup.
Speedometer
Well, it's been a long time coming, but I finally got my speedometer working correctly. After many trails, and misinformation from other sites, its finally working. Let me first say that not all '99 4Runners are the same, and there are many differences between models. The following information pertains to the '99 4Runner Limited, which is particularly difficult to get working due to the multimatic transfer case and ABS speed sensors. So, don't think this info is going to solve your '99 SR5 4Runner woes, I would look at it as more of a guideline, then the actual solution. That said, lets get into it.
Some time ago, I had purchased the SuperLift TruSpeed. I must confess, this was the biggest waist of money I have ever spent. The directions were incorrect and the unit never worked as claimed by the manufacturer. In fact, upon calling the manufacturer about this, their response was less than helpful, actually it was darn right lame. Now, this doesn't mean it won't work for you, I'm just relaying my experience with this waste of a product.
So, in the meantime, I used my GPS as my speedometer. With 3 trips to Moab, 1 trip to Arizona and a few to Farmington, I figure I'm at most 3500 miles off of what my current odometer states.
Ok, on to the real issue. The '99 4Runner Limited uses the ABS sensors at each wheel as speed sensors. The method of the madness is;
The ABS sensors feed the ABS computer - The ABS computer then sends a single speed signal to the Speedometer in the Combination Meter - from there it goes to the ECU. Yes, its a long route, but apparently it works.
Lets start off by taking a look at this picture of the ABS computer and the speed sensors that are attached to the computer. Click on the picture below to open it in a different window.
When looking at this picture, notice the 4 speed sensors, one for each wheel. They are essentially Hall-effect sensors that generate a voltage signal when a piece of steel is move across the face of the sensor. So, this is the root of the issue. When Folks perform a SAS (SAC) the front sensors are removed. This action alone will not stop the speedometer from working, but will bring the ABS light on. In cases such as mine, when folks perform a Full Floater setup for the rear axle, again, the sensors are removed. Thus, without speed sensors, you have no speedometer.
There are some out there who are trying to sell VSS (Vehicle Speed Sensor) units that will attach to a mechanical speed sensor and create a voltage signal. Let me tell you first hand, be careful of what is told to you. Do you own research. I was told by a person of a reputable company some bad information that cost me fifty dollars. After doing the research myself, I figured it out and obtained the correct parts. These gear driven speed sensors do not span a wide range of transfer cases as was stated to me. I would say the company makes some innovative off-road products, but doesn't know too much about speed sensors, as they would imply. Just be careful.
OK, back to the picture. Here you see the speed sensors and you can also see the wire that goes to the ABS light. So, instead of pulling the instrument panel to get to the ABS bulb, just clip the Black wire with Light Blue stripe. This wire comes out of Port 25B on the ABS computer.
This picture is the previous page to the above picture. Notice that if you clip the Black wire with the Light Blue strip, it goes the the ABS light in the combination meter. it also goes to the ABS relay, if you have one. In my case I didn't have a relay, so no worries there.
Also note in this picture that connector 14 on the ABS ECU connects to the Speedometer in the Combination Meter. This Gray wire with Light Blue strip goes directly to the speedometer. What does this mean? Again, you don't have to pull your instrument cluster apart to get to this wire. After hooking up my Tacoma speedometer, I ran the signal wire up through the transfer case boot, underneath the carpet directly to the ABS ECU. I clipped the wire coming out of the ABS ECU and patched my speed signal wire directly into the wire leading to the Speedometer in the combination meter.
Here is a picture of the Combination meter, (pin 1D) receives the speed sensor signal from the ABS ECU, or the VSS, depending on your type of rig. Note the GR-L wire has a note indicating number 1 next to it. This means "5VZ-FE". Also note that the same pin, 1D has an alternate number, 2, going to the VSS. This number two means 3RZ-FE. As well, the 9D pin has the Pink wire going to the VSS for the 3RZ-FE engine style rigs. I assume that when the Combination meter gets power, it powers the VSS, and receives a speed signal back from it via pin 1D. In the case of 4Runners that had ABS as speed sensors, the A17 ABS ECU would apply. Tap into this line to send the signal to the Combination Meter.
Pretty simple right, well....not so fast. One thing you really need to do is get enough voltage to the speed sensor to send a strong signal to the speedometer. My first attempt at this was to hook the hot wire of the speed sensor to a fuse. Not enough voltage. So, you need a good voltage source and a good ground. As noted below, I used the cigarette lighter relay to power my VSS.
I was able to find this picture on the internet and resize it to show what the '98 Tacoma VSS looks like. The VSS I pulled came from a '98 Tacoma with a V6, automatic transmission and chain drive transfer case. I picked up the whole thing for seventy-five dollars, which is a pretty good deal compared to the dealerships asking price of $225. Be sure you get the plug when you get the VSS. You're gonna need the plug with the wires. You may also consider testing the unit before you leave the junk yard. Take a couple of alligator clips and a voltage meter. Follow the wire settings below, turn the gear by hand and see if you get a voltage drop from 12v to 0 volts, and it repeats with more turns.
This unit has 3 wires:
Pink, Light Blue and Green with Red stripe.
Pink goes to power, a good 12 volt source. I have heard of people wiring these directly to a hot power source, but I felt this not a good idea. Who knows what could happen if the wires get too hot. What I really needed was a relay to turn the power on and off with the ignition. I hooked the hot wire directly to the Cigarette lighter relay in the engine bay. When the 4Runner is on, and running, it has power. When its off, it no longer has power. Now for those how have shorted out the relay to always have power, this isn't gonna work for ya. But, in my humble opinion, a relay is the best way to power this unit.
The Light Blue wire goes to a good ground. I was able to route this wire up through the transfer case boot to a ground source in the center consol. Works like a charm.
The Green with Red stripe wire is your signal wire. This wire will connect directly to the Gray wire with Light Blue stripe.
Here is a picture of the speed sensor installed, showing the wire colors. As well, I labeled the wires in the picture. The picture shows how the wires come out of the sensor, from the front of the vehicle to the rear. For those of you who didn't get the plug (pig tail) that goes into the speed sensor, you can use this picture to match up the wires to the correct sensor wires. Pink=Power, Light Blue=Ground, Green w/Red Stripe=signal.
Now to test it. put the rear of the 4Runner on jack stands, put it in gear and see if the speedometer moves. If so, your in business. Of course, with tire changes, it probably will not read correctly.
Dakota Digital makes a really great product that will modify your speed signal and give the speedometer the correct signal.
I was able to pick up one of these units for $80 bucks off ebay. They have great instructions and work very well. One thing I wish they had was a dual switch that would allow me to switch between two different settings, such as for 37" and 35" tires. That would be cool.
So, there you go, this is how you can get a working speedometer after removing ABS sensors from your rig. Now, I remind you, this was done on a '99 4Runner Limited. Does this mean that all colored wires are the same for your rig? No. I would use this information as more of a guide than step by step factual instructions for your rig. As well, just because I have stated that this is working for me, doesn't mean it will work for you. I don't know what the electrical issues are on your rig. You may end up trying this and shorting out your Combination Meter. Take responsibility for your actions and research what you are doing before you do it.
Grey Wire Locker Mod
There are numerous write ups on how to bypass the default setting for only allowing the locker to be engaged in 4lo. Here are some images I have gathered from another person who has done it. Pretty simple actually.
http://www.4x4wire.com/toyota/minutemods/greywire_mod/
The pics below are from the following site. Great article,
written by Jason UALairmech21@aol.com
http://www.offroaders.com/info/tech-corner/reading/Toyota_Tacoma_locker.htm
Disclaimer: What you see on these pages are my own experiences and what changes I have performed on my vehicle. Should you choose to attempt these type of changes to your vehicle, I am not responsible for any consequential damages that may result from these type of modifications. I do not encourage any readers to copy these modifications to their own vehicle. Modifying your vehicle can be dangerous to you and anybody else on the roadway. Please take care in what you do with your vehicle.