Toyota 4Runner Technical Information

Toyota 4Runner/Pickup Technical Information

Here's various bits and pieces of technical specifications, etc. that I've collected about my 1985 (1st generation) 4Runner:

Dimensions Steering Engine Drivertrain
Differentials Fluids Shell Electrical
Suspension VIN EFI Wheels/Tires

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Dimensions:

Length 174.6"
Width 66.5"
Height

66.1 (stock)

~72" (lifted)
Wheelbase 103" stock
106" w/ rear spring swap
and dropped spring hanger
Tread (Track)

55.9" (F)

55.1" (R)
GVWR 4800 lb.
Cargo 700 lb.
Fuel Tank 17.2 gallons
Wheels 15x6J / 3-3/8" backspace
Tires 225/75R/15 (~28x9)
Table: Dimensions and Weight
Notes:
4Runner has the same frame dimensions as the std. cab pickup of the same vintage
The early Xtra cab and long bed pickups are ~113" wheel base
Click here for a scan of the FSM frame dimension drawing
Factory paint color codes
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Steering:

Toe In 1mm ± 2mm
Camber 1°45'± 45'
Caster 2°00' ± 1° 4Runner
2°15' ± 1° pickup
Steering Axis Inclination 9°30' ± 45'
Turning Angle: Max Angle

Inside: 30°30'

Outside: 29°
Turning Angle @20° Outside Inside: 20°30'
Table: 1985 Toyota 4WD Steering Geometry
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Engine:

engine

Model 22R-EC
Bore 92mm
Stroke 89mm
Displacement 2366cc
Power 116 HP @ 4800 RPM
Torque 140 lb-ft @ 2800 RPM
Compression 9.2: 1
Fuel 87 Octane
Table: Engine Specifications
Cam

Intake

Duration

Exhaust

Duration

Intake

Lift

Exhaust

Lift
22R 272° 248° 10.1mm 9.7mm
22RE 248° 280° 10.0mm 9.7mm
Table: Stock 22R Cam Specification

Notes:

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Transmission/Transfer Case(s):

gears

The Aisin Seiki W56 is a five-speed, fully-synchronized manual transmission is found in Toyota 4x4's with the 22R-E engine:

Gear Ratio
1st 3.954
2nd 2.141
3rd 1.384
4th 1.000
5th 0.850
5-Speed Manual Transmission

Or the A340F 4-speed automatic transmission:

4-Speed Automatic Transmission
Gear Ratio
1 2.80
2 1.52
3 1.00
4/OD 0.71

The Aisin Seiki RF1A two-speed transfer case is found in Toyota 4x4's:

Gear Ratio
Hi 1.00
Lo 2.28
Gear-Driven Transfer Case

With a Marlin Ultimate Crawler (dual transfer case), 5.29:1 R&P gears, overall crawl ratios work out to:

5.29 - Final Drive Ratios
Front Rear 1st 2nd 3rd 4th 5th
1.00:1 1.00:1 20.9 11.3 7.3 5.3 4.5
2.28:1 1.00:1 47.7 25.8 16.7 12.1 10.2
1.00:1 4.70:1 98.3 53.2 34.4 24.9 21.1
2.28:1 4.70:1 224.1 121.4 78.5 56.7 48.1

With a Marlin Ultimate Crawler (dual transfer case), 4.88:1 R&P gears, overall crawl ratios work out to:

4.88 - Final Drive Ratios
Front Rear 1st 2nd 3rd 4th 5th
1.00:1 1.00:1 19.3 10.4 6.8 4.9 4.1
2.28:1 1.00:1 44.0 23.8 15.4 11.1 9.5
1.00:1 4.70:1 90.7 49.1 31.7 22.9 19.5
2.28:1 4.70:1 206.8 112.0 72.4 52.3 44.4

Notes:

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Differentials:

Below is some information on the 8" Toyoya 3rd members/differentials:

Ratios:

Toyota 8" 3rd member

Here is a table of ring and pinion sizes for various gear ratios in the Toyota 8" differential:

(typical axle ratios for manual transmission equipped trucks, 28" stock tires)

Table: Ring and Pinion ratios
Ratio Ring Pinion Factory
Color
Code		 Crawl Ratio
(stock)		 Tire Size
to stock
M/T		 Tire Size
in use
M/T		 Tire Size
to stock
A/T		 Tire Size
in use
A/T
3.42 41 12 Purple 31 : 1 . . . .
3.90 39 10 none 36 : 1 . . . .
3.93 . . none . . . . .
4.10 41 10 Pink 37 : 1 28 28 . 28
4.11 37 9 Orange 37:1 pre-'82 28 28 . 28
4.30 . . Blue . 29-30 29-30 28 28
4.37 35 8 Green 40 : 1 30 29-30 28 28
4.56 41 9 Yellow 41 : 1 31 29-31 29-30 29-30
4.88 39 8 White 44 : 1 33 31-33 31 31-33
5.29 37 7 none 48 : 1 36 33-36 33 33
5.71 40 7 none 51 : 1 39 37+ 35 33+

There are 4 common factory gear ratios for the '84-'95 pickups and 4Runners. What ratio your truck has depends on what type of transmission it came with (manual/4 speed) or automatic) and whether it came with the factory 31" tire option (early '90s SR5 option) or the normal 28" (P22575R15) tires, as noted below:

Tranny/Tire 28" 31"
Manual 4.10 4.56
Automatic 4.30 4.88

How to determine what ratio you have:

You can look up the factory axle code for a given vehicle using this table. Or refer to the paint code on the end of the pinion flange shaft, as shown in the image below:

Factory 4.10 pinion with pink paint

Note that the color codes above are not an absolute way to determine gear ratio, nor is the vehicle's model info/VIN sticker. However, if you have an axle/differential off of an unknown vehicle or it has aftermarket gears, then you'll need to determine the ratio. If the differential is out, count the ring and pinion gear teeth (or that data is often stamped into the ring gear).

If the differential is still installed inside an axle, then assuming you have open differentials, lift one wheel on the axle in question off the ground. Put the tranny in neutral, transfer case in 2H, e-brake off (if is the rear axle you are testing) and put a chalk mark on the driveshaft and on the tire. Now turn the tire in the air through 2 full revolutions, while counting the revolutions that the driveshaft makes. The number of which will be equal to your gear ratio. You can get a more accurate count by doing 10 or 20 wheel revolutions and dividing the driveshaft turns accordingly.

Why 2 wheel revolutions?
Because, the ring gear in an open differential turns at the average speed of the two axle shafts connected to it. Since one is on the ground (and thus not turning) the other axle shaft (i.e. the one you are turning) must turn twice as fast as the ring gear, so 2 revolutions on one axle + 0 revolutions on the other shaft averages out to 1 revolution on the ring gear.

If you have a limited slip or automatic locker, then you'll need both wheels in the air and you'll use just one wheel revolution to get the rear ratio. For better accuracy, you can use say 10 (or 20) revolutions and then divide your drive shaft revolutions to get the gear ratio. For example, the difference between 4.56 (a little over 4-1/2 revs) and 4.88 (a little over 4-3/4 revs) might be hard to distinguish, but if you did 10 times as many revs on the wheel, you magnify the difference at the driveshaft by 10 as well. So instead of say 0.32 revolution difference (4.88-4.56), you would now have 3.2 revolutions difference if turning the wheel 10 (or 20) times.

Note that you may get different readings on the gear ratio with the above methods. Least reliable method is likely the "paint code". Next up the list in reliability is the vehicle VIN plate. It should be accurate given the diff in the vehicle is still the original one or that you know that VIN info from the vehicle the diff came out of. The wheel spinning technique should give good information with good technique. But it can give you misleading information, too. I once tested a diff I had and it seemed to do right at 4.5 axle shaft rotations for 1 pinion rotation. Fugured it was a 4.56 until I counted the teeth and found it to be a 4.10. So a tooth count is the most accurate test, but also the hardest to do if the diff is bolted up to the axle housing.

Types of Toyota 8" 3rd Members

4 Cyl. Rear 8" 3rd Member 6 Cyl. Rear 8" 3rd Member
4Cyl/8" V6/8"
Toyota 8" High Pinion 3rd Member .
HighPinion/8" .

Above are photos of the various Toyota 8" 3rd member housings. All the housings are interchaneable in that the mounting studs and axle splines are identical. The 4 cyl differential internals are different than the V6 and High Pinion, so that lockers and limited slips are different. The 4 cyl ring and pinion gears are somewhat smaller overall than the V6 parts, i.e. the ring gear is thinner and the pinion gear and bearing are less substantial. The 4- and 6-cyl housings can be distinguised by the number and style of reinforcing ribs present.

The 4- and 6-cyl housings may be used in rear or front applications. The pinion (or companion) flange nut takes a 30mm socket.

The High Pinion diff uses reverse cut gears and is best suited for front solid axle applications. While it shares internals with the V6 diff, the gears are unique to the High Pinion due to the reverse cut, which puts the gears on the drive side of the teeth in the front axle. High pinion diffs are commonly found in 1990-1997 FJ-80 and FJZ-80 model Landcruisers that had the solid front axles. Ironically, the high pinion diff was not designed for the added ground clearance, but rather so that the steering tie rod on the FJ-80 could be run *below* the front driveshaft to keep the vehicle low!

Reverse Cut vs. Standard Cut

Perhaps the single most misunderstood axle term is reverse cut, often mistakenly referred to as reverse rotation. A reverse cut housing is not standard cut housing turned upside down, it is a specially designed housing, most notably with internal mechanisms to aide in pumping gear oil up to the high-mounted pinion gear and bearings for proper lubrication. The term "reverse cut" refers to the direction of the spiral cut in the ring gear, which is opposite that of a standard cut ring gear. Contrary to popular belief, it does not run backwards or in reverse. The principle behind a reverse cut is to strengthen the operation of the gear when it is used for a front driving axle application. See below for an illustration of the ring gear tooth nomenclature and construction. As you can see, the drive side of the gear tooth is nearly perpendicular to the direction that the pinion gear tooth pushes on it, making for an efficient transfer of force. The coast side on the other had, is angled away from the direction of force, this causes the pinion gear to want to "ride up" on the ring gear teeth under load, lessening the area of contact and moving it out towards the thinner ends of the teeth vs. the thicker root of the tooth. As such, it is generally the case that a ring/pinion gear set is 30% weaker when run in the reverse direction. This is not normally a problem, as you rarely see the kinds of loads in reverse that you see when going forward. Likewise, a front axle usually has less load on it that a rear axle, like when climbing up some steep obstacle (i.e. less weight and traction up front) so its common to run a rear differential in a front axle. The 4- and 6-cyl gears will run on the coast side in the front axle, likewise, a high-pinion, reverse-cut differential will run on the coast side in a rear axle application. While the 30% strength reduction sounds like a major design problem, it should really be looked at from the standpoint of an perfectly symmetrical gear tooth. In this case, using the non-symmetrical tooth geometry gives a gear that is 15% stronger in the forward direction and 15% weaker in the reverse direction. While 15% one way or the other doesn't sound like a lot, its enough to make an 8" ring gear, properly cut, as strong as a 9.25" ring gear with symmetrical teeth. However, looking at it the other way of using a reverse cut gear in a rear axle, the 30% strength reduction makes an 8" ring gear only as strong as a 6" gear with normal cut teeth. One way to reduce the load on the gear is to reduce the weight of the vehicle its driving. For example, if the normal cut gear was designed for a 4000 lb. vehicle, reducing the vehicle's weight to under 3000 lbs. will reduce the load on the reverse cut gear in a rear axle to the point it may be strong enough to handle the load.

Gear Tooth Nomenclature

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Other information:

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Fluids:

Fluid Specifications
Type Grade Amount
Gasoline 87 pump octane unleaded
(=91 research octane number)		 17.2 gal.
Engine Oil SF/CC, 10W40 4.9 qt.
Coolant Ethylene-glycol 8.9 qt.
Manual Transmission GL-4/5, 75W90 22R: 4.1 qt.
22RE: 3.2 qt.
Transfer Case GL-4/5, 75W90 1.7 qt.
-Dual Transfer Case GL-4/5, 75W90 +0.7 qt.
Front Differential Hypoid GL-5, 80W90 2.4 qt.
Rear Differential Hypoid GL-5, 80W90 2.3 qt.
Power Steering Automatic Transmission
Fluid - Dexron or Dexron-II		 ~1 qt.
Brakes DOT-3 ~1 qt

More Information:

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Shell:

The 1st generation 4Runners feature a fiberglass shell over the rear seat and cargo area. This shell may be removed and installed with the following procedures. You'll need a 12mm wrench or socket for the shell bolts and a Philips screwdriver for the trim.

Refer to the fastener letter designations in the image below for the removal and installation steps below:

Rear shell bolt information
Shell Fastener Designations Cover Top Bolts:
A below, B-E above

Removal:

Here are a few tips I found helpful for removing the shell:

Note:

Installation:

Shell Storage:

So, you have the top off, now what do you do with it?

Shell hanger detail Shell Storage
A: Shell Hanger Detail B: Shell Removal

Here's how I remove and store my cover top (i.e. shell) in the garage.I can do this process all by myself, so no need to try and round up a neighbor or friend to come by to help.I use 4 cargp straps, not the ratchet type - those only have a limited take up length, but use the toggle-clamp style as shown in image A above. They are attached to 4 bicycle hooks screwed in the rafters of my garage. All these items came from the local hardware store.

The hooks are spaced wide enough to clear the sides of the top and far enough apart to line up with the front and rear windows. Then, I use some old aluminum roof rack bars, to which I fasten screw eyes to the ends (again parts from the local hardware store_. They are just wider than the top is, a pair of 2x4s would work, too. I slide the front window back and slide the bar though the opening. Then, I lift the top up with my shoulders and pull the straps tight on each side. This is one reason why I chose to use the open front windows for the forward support bar as there is no way (for me alone) to slide a support bar under the shell in front until it is lifted. And it is generally not possible to lift the rear of the shell first since the roof part will be pushed into the back of the cab, so this is why the front end must be lifted first (and also lowered last). And the final advantage of supporting the front of the shell with a bar through the windows is that when I have the shell lifted with my back/shoulders, it is easy to reach out the open window and take up the slack in the cargo strap.

Then in back, I lift the top up and slide the bar under the rear corner. I can reach out of the open rear window ro snug up the straps, or I can hop out and kift a corner and snug up that strap as needed. Then, its a matter of alternately lifting the ends of the cover top up and snugging up the straps until the top is against the rafters and then I simply drive out of the garage (I have to air down to 3 psi to get my 4Runner under the garage door!). To install is the reverse, back in, lower the and align the cover top, remove the bars and install the bolts. Simple, one person install and removal, no danger of dropping the top, either.

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Electrical:

Fuses:

Driver's side fuse panel:

Rating Circuit Rating Circuit Rating Circuit
15A Rear Defogger 15A Cigarette Lighter 10A Stop Lamps
15A Tail Lights 15A Windshield Wiper 7.5A Dome Light
15A EFI Circuit 15A Engine 7.5A Ignition
Driver's Side Fuse Panel Circuit Assignments

Engine Fuse Box:

22RE Engine Fuse Box
Designation Rating Function
AM1 40 amp Fusible Link / Gas Engine
- AM1 60 amp Fusible Link / Diesel Engine
AM2 30 amp Fusible Link / Gas Engine
- AM2 80 amp Fusible Link / Diesel Engine
Head 30 amp Headlight Relay
Head(RH) 10 amp Right Hand Headlight Fuse
Head(LH) 10 amp Left Hand Headlight Fuse
Charge 7.5 amps Alternator Charge Fuse
Haz-Horn 10 amps Hazard Light / Horn Fuse
- also Turn Signals
Fuel Heater ? Fuel Heater / Diesel Engine

Senders:

Sender Low (ohms) High (ohms) Sender
Thread
Fuel Tank 110 = Empty 3 = Full n/a
Oil Pressure = = 1/8"x28 BSP
Coolant Temp. 24 = Hot/239F 147 = 140F/Cold .
Cold Start Injector
Time Switch		 STA-STJ=20-40
below 30°C		 STA-STJ=40-60
above 40°C		 STA-Gnd
20-80
Injector Resistor 2 - 3 ohms each
No10 or No20 to B+		 . n/a

Factory Service Manual Wiring Color Codes:

In the FSM Wiring Diagrams, wire colors are referred to in a 1- or 2-letter code as designated below. The codes below appear in the Body Electrical (BE) section of the 1985 4Runner FSM and are used in the wiring diagrams at the back of the manual:
Code Color
B Black
G Green
L Light blue
O Orange
R Red
W White
BR BRown
GR GRey
LG Light Green
P Pink
V Violet
Y Yellow
And color code "X-Y" means X-color wire with a Y-color stripe

Other Electrical Links:

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EFI:

Recently, I opened up the intake side of my engine to inspect and clean the intake. This was prompted by a peek inside the throttle body, that revealed a thick layer of black goo. Upon removing the air plenum, I noticed a liquid in the bottom of two of the intake runners. A strong smell of gasoline suggested its source, the injectors must be leaking. After removing the fuel rail, the injectors just pop out of the intake manifold. They were a bit dirty, some solvent seemed to remove the surface grime, but I suspected, after 220,000 miles of use, they may be dirty inside. So, into a box and off to R.C. Engineering they went for the standard clean, calibrate and balance service. Three days later they arrived on my doorstep looking brand new with the following calibration report:

________Before__________After
Injector cc/min Pattern cc/min Pattern
1 178.4 Dripping 184.1 Excellent
2 171.5 Fair 182.9 Excellent
3 177.9 Good 183.5 Excellent
4 179.0 Good 184.0 Excellent

Freshly cleaned injector

All 4 injectors tested out at 3 ohms on my meter. Prior to service, the system balance was +/- 4.4%, afterwards 0.7% and total fuel flow increased from 67.31 to 69.95 lbs/hr, about a 4% increase, hopefully that will translate into some additional power at the wheels. All in all, a well spent $100.

Here's some related 22RE information:

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Wheels/Tires:

Stock wheels:
15x6 steel
3-3/8" back side spacing (on '85 and earlier wheels)
4-3/4" back side spacing on '86 and later wheels, 15x6 steel or 15x7 alloy
Here's a good backspace to offset calculator
Center bore diameter: 4-3/8" (111mm) ID
To fit over front hubs which are approx. 4-1/4" (or 106.1mm) OD
And of course this implies a lug-centric wheel since the center bore is larger than the hub
Beginning with the 3rd generation 4Runner and Tacoma models, wheels were changed to hub-centric
6 on 5.5" bolt pattern
M12x1.50 thread pitch studs
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[Last updated: 13.October.2023 ]