Troopers

Axles

The Trooper features an independent front suspension design. However, unlike many IFS systems of the era, the design Isuzu utilized is quite strong and will hold up well to abuse. The front differential is one of two different models: the Isuzu Corporate 8-bolt, or the Isuzu Corporate 10-bolt. The 8-bolt was used in Troopers until mid-87, where the entire front suspension was changed and the 10-bolt was incorporated into the design. The 10-bolt front axle was used in Troopers from mid-87 until the final Trooper rolled off of the production line. All Troopers featured front disc brakes.

The rear axles are slightly more varied than the front. The Isuzu Corporate 10-bolt rear axle was used in combination with the 8-bolt front axle in the pre-88 model year trucks. It's not nearly as strong as the 12-bolt and also features drum brakes. In mid-87, the Trooper received a major upgrade to the rear end in the form of the 12-bolt axle. The 12-bolt introduced disc brakes to the rear of the Trooper, providing a boost in stopping power and torque handling in preparation for the 2.6L 4ZE1. Slight modifications were made to the axle design in 1991 (for accomodating the new 4-link coil-spring suspension and wider track of the '92 model year). In 1995 roughly 2 inches was added to the width of the rear axle for the wide-track Trooper (along with longer front axle shafts), although all other features such as spring perches and link mounts remained unchanged. All 12-bolt axles from 1992 through 1997 featured a 4.56 gear ratio. For the 1998 model year, significant changes were made to the axle, including thicker axle shafts and different spline count, resulting in the Modified 12-bolt axle (with 4.30 gears). Most internal parts of the Modified 12-bolt are not interchangable with the regular 12-bolt axle. Note that the bolt count is the bolts in the ring gear not the pumpkin to the housing.

The Trooper has always had a rather high rear axle ratio. 4.56 (41/9) ring and pinion gear sets were used in the 1984 model Troopers all the way up until around 1998, when 4.30 (43/10) gear sets were used due to the availability of much torquier 3.5 liter V6 engines. The only exceptions to this were the 1987 turbo diesel trooper (it was available for one year only and only 200~ of them came to the USA) 4.11 gears were used from the 4x4 81-87 pup to slow the engine RPM at highway speeds so a 86 T\D trooper can be upgraded to 4.11 by taking the gears from a 4x4 isuzu pup; and the 1989 RS Trooper, which used a 4.77 gear ratio. 4.77 gears were reportedly also available in some 4-door first-generation models with the "Big Tire" option package.

Wheels

The bolt pattern for Troopers is 6x5.5 with a 108mm (4.26") center bore. Many Toyota and Nissan stock wheels will fit, but most GM wheels have center bores that are too small (78mm center bores). Some mid-80's GM trucks and K5 Blazers do have factory wheels with a larger center bore that fit however. Note that the Canyon/Colorado have 6x5.5 bolt patterns with 100mm bores, and Trailblazers/Envoys have 6x5 bolt patterns.

Lugnut sizes is 12x1.5mm with with 60* conical end for factory Isuzu wheels. If using Toyota wheels most Toyota wheels have a stepped shoulder and are hub-centric, that's why they use lugs with straight shank and washers. The Toyota wheels have a large enough hole to fit over the Isuzu hub, but will not center because the diameters are off. Isuzu factory mags are lug-centric and the wheel centers about the lug holes only and not the center hub.

Timeline

1984-1987 early First Generation Trooper

• 1984 - Isuzu introduces Trooper into U.S. 1.9l engine. 4 speed transmission. Automatic locking hubs. 10 gallon gas tank (identified by the gas filler in front of the rear axle). Round sealed beam headlights. Antennae on drivers side windshield pillar. Two doors. Rear seat has horizontal sliding windows. 15x6 rims with P225/75/15 tires

• 1985 - Won the 4x4 of the year from Petersons 4wheel drive magazine.

• 1986 - Isuzu Introduces Trooper II into U.S. (This was the same as a Trooper, but with no rear seat at the time of import, so it was imported at a lower tariff rate as a truck. Rear seat installed by dealer). 2.3l carbeurated engine, or a 2.2L turbo diesel bolth had a 5 speed MSG-5 transmission only made for 86-87 troopers and pup 4x4s. 10-bolt (Isuzu Corporate) rear differential. 8-bolt (Isuzu Corporate) front differential. Tachometer added to gauge cluster. New gauge cluster added between center vents with oil pressure, temperature and gas gauge. 4 door model offered. Two door model has same body as previous years. Rear spoiler (used to keep continuous air flow across rear doors to help prevent exhaust gases from entering) and roof rack offered as options. Air conditioning a non-Isuzu dealer option. 21.5 gallon fuel tank located behind the rear axle. Alloy wheels on LS model.

1987-1991 late First Generation Trooper

• 1987 - Transition begins. Square headlights like later models. Same driveline as 86. Some report 12-bolt rear end and 10-bolt front end differential, though officially the 10/12 combination was not released until the 1988 model year. also last year for 2.2L T\D engine. first year for LT235/75/15 tires.

• 1988 - 2.6L 4ZE1 (121hp / 146 lb-ft) fuel injected engine introduced. MUA-5 5 speed manual transmission standard with Aisin-Warner A340H 4 speed automatic as an option on the 2.6L. 12-bolt Isuzu rear differential introduced. The 10-bolt rear diff used in rear of '84-'87 Troopers moved to the front in the improved IFS. Antenna located on front passenger's fender. Rear step bumper on LS and higher models with tow package. A "Special Edition" Trooper featuring special badging and a split rear seat that converts to a bed was available this model year only. (Note: the split rear seat that reclines all the way down to the cargo area behind the seat was available in later years as well).

• 1989 - Short wheelbase RS version with 4ZE1 2.6L is produced and available in the US only in this year. On long wheelbase models, the GM 2.8L V6 (LL2) is introduced as an option as well as the 4 speed GM 4L30E automatic transmission, available on the 2.8L V6 only as the 4ZE1 2.6L was paired with the A340H - an Aisin transmission. All 4L30E and MUA-5 manuals had gear driven transfer cases, while the A340H had a chain driven transfer case.

LS, S, XS, and limited versions available. 2-door available in S and XS. LS and S commonly available. XS and 2-door models available in select areas.

According to Jerry Lemond, the '84-88 2 door was the long wheelbase version, the same length as the 4 door as only one chassis was used in those years. The distance from the rear edge of the door to the front of the rear wheel well opening is roughly 22.25 inches on the long wheelbase 2 door model. All 2 doors in '89-91 were short wheelbase, as all 1st gen regular length (long wheelbase) Troopers after '88 had 4 doors.

S model is base with a metal lined interior and only available with 15x6 steel wheels, although 15x7 aluminum wheels with 31x10.5x15 tires were an option on all trim levels, but apparently with the 2.6L only. All 15x6 rims received 235x75x15 tires, and auto-locking hubs were standard with the manual transmission. Interestingly, according to the '89 sales brochure the rear wind deflector was only available on the S trim.

The LS is a higher end model with chrome trim, cruise control, lower dash cover to hide wires underneath the steering column and glove box, power windows and power door locks, chrome front bumper, privacy glass,retractable cargo cover, reclining front captains chair with adjustable armrests, reclining split back rear seat, velour upholstery, rear step bumper, built-in trailer hitch and aluminum 15x6 wheels.

The XS is positioned between the S and the LS, they did not have power windows or power door locks like the LS and had different trim, and was available only with the 2.6L like the RS. Interestingly also, the folding rear seat option was only available on the S and XS.

Curb weight is listed as 3600/3680 manual/auto for the 4 door, but actual weight of a 1990 2.8L manual was 4056 at the scales.

1992-1997 Second Generation Trooper

• Isuzu's completely redesigned Trooper, introduced 1991 in Japan,was bigger than the old ones at 4510 pounds and was in keeping with the trend of making SUVs larger, more powerful, and more luxurious. These vehicles used a 3.2 L single overhead cam (SOHC) model that put out 175 hp (130 kW), with an available 3.2 L dual overhead cam (DOHC) engine rated at 190 hp (142 kW). A SOHC 3.2 L engine producing 190 hp (142 kW) was introduced in 1996, replacing the prior engines. Most models, with the exclusion of the 1996 SE Limited, still used a part-time four-wheel drive system, which required stopping the vehicle to engage and disengage the front axle. The 1996 SE Limited model came with shift on the fly engagement. Models after 1996 included the same shift on the fly arrangement.

1998-2002 Second Generation Trooper

• Beginning in 1998, Troopers in the US were equipped with a DOHC 3.5 L engine producing 215 hp (160 kW). European and Asian buyers could opt for a 4.0 L diesel, and other diesel engine options appeared later on, including the 4JG2 3.1 L (later superseded by the more problematic 4JX1 3.0 L). At this time, the introduction of the Borg-Warner Torque on Demand system provided an All Wheel Drive setting. Freshened styling also debuted at this time, and the grille was redesigned again for the 2000 model year.

Powertrain and Transmissions

Isuzu Troopers have come equipped with a wide variety of powerplants, with each successive 'generation' featuring a more powerful engine or an engine with a different fuel type.

Engine Displacement (Liters)
1st Generation 1984-1991
1.9L 4-cylinder, G200Z, gasoline,Isuzu make; carbureted;(North American market)
2.2L 4-cylinder, C223-T, turbo diesel, ISUZU make; fuel injected;(North American market)
2.3L 4-cylinder, 4ZD1, gasoline, ISUZU make; carbureted; (North American market)
2.6L 4-cylinder, 4ZE1, gasoline, ISUZU make; fuel injected; (North American market)
2.8L V6, LL2, gasoline, GM make; throttle body injected; (North American market)

Second Generation 1992-1997
3.2L V6, 6VD1, gasoline, ISUZU make; fuel injection; SOHC version in S trim level (175 to 190 horsepower depending on year), DOHC in LS and RS trim levels (190 horsepower). (North American market)

Third Generation 1998+
3.5L V6, 6VE1, gasoline, ISUZU make; fuel injected. This particular engine has gone through several design developments. Initially coming out in DOHC configuration, the last incarnation featured cutting edge 'direct injection' technology most commonly found in the ISUZU Axiom, the last ISUZU SUV model produced in the North American market (the direct injection version was never used in the Trooper). The 3.5L engine was featured in the Trooper from 1998 through 2002 (North American market).

Transmissions

History of the 4L30-E transmission.

It all starts back in the 60’s and early 70’s. Opel, the European car manufacturer starts selling their Kadett, Rekord and other models with the then popular “Trimatic” and later called “TH180” automatic transmissions.

After adding a converter clutch this trans became known as the “TH180-C”. In the USA the “TH180-C” got it’s fame under the name 3L30. Throughout this period all GM transmissions were and still are produced at the General Motors plant in Strasbourg, France. As both Opel and Buick were part of the General Motors group, Opel reached the US market through the Buick dealerships.

For reasons only GM knows they decided to add an overdrive to the 3L30. As the main case of the 3L30 could not accommodate the overdrive they were forced to put it in it’s own case and mounted it in front of the 3L30. The 4L30-E was born ! This adaptor case has it’s own valve body and even it’s own oil pan.

The 4L30-E became so popular that other car manufacturers started using it. You can find this transmissions on Isuzu Trooper and Rodeo’s, BMW’s 3 and 5 series and probably a few more brands.

The 4L30-E designation system is as follows:

4 = Four speed, L = Longitudinal, 30 = Series based on torque capacity, E = Electronic controlled.

Trimlines

• XS - 2-door model with the same wheelbase as the 4-door models.
  
• S - The S model Trooper is the base model Trooper. In the 1989-1991 models, the S trim featured black B- and C-pillars and single-tone paint.
  
• LS - In the 1989-1991 model year, the LS featured two-tone paint with chrome trim strips around the windshield, down the sides and, around the wheel wells, and chrome door handles. The B- and C-pillars along with the front window edging was body colored. Interior enhancements featured electric windows and locks, leatherette steering wheel, velour interior, cruise control, and folding rear seats with removable wing extensions that permitted turning the rear seats into a bed of sorts. The LS trim also included a rear wiper with washer sprayer. Ironically, many of the LS trimmed Troopers came with the MUA-5 manual transmission. These Troopers also featured a 'comfort ride suspension' meaning softer shock absorbers. The LS Troopers also came with chrome bumpers front and rear with the rear bumper featuring a ball-hitch middle section. Carpeting was included in these units as well.
  
• SE - The Second Generation Trooper SE was commonly referred to by dealers as the "Super Trooper" It included the two tone paint and color coordinated bumper covers and rocker cover trim panels. It had most of the available options as standard, including the huge power sunroof, leather seating, power seats, power mirrors (heated, adjustable and swing out or in by electric control) and front headlamp wiper blades and washers, to name a few.
  
• RS - Short wheelbase, 2-door models. While commonly available worldwide, few RS models were imported in the US. First generation RS Troopers were imported in 1989 only. Second generation Troopers were imported primarily in 1993, with a very few also in 1994 and 1995. The second gen RS is essentially a 4-door Trooper with 17 inches cut out of the middle. Almost all parts are interchangable with 4-door models, except for the "pop-out" side windows for the 2nd row passengers (as opposed to roll-down windows in the doors for the second row in 4-door models).

Options

Early (pre 1988) Troopers had an optional rear-seat heater. The heater mounted under the passenger side front seat. Hoses ran under the floor and connected where the normal heater-core hoses do. There was a fan speed control knob next to the headlight knob on the left side of the steering column.

1st gen Troopers had optional spoilers. These mounted above the two rear doors and had two effects: 1) it helped to keep the rear windows clean by directing a flow of air across them. 2) it helped keep exhaust gases out of the truck by directing a flow of air across the back of the truck.

Pre-1988 Troopers could get a clock mounted where the cup-holder is in the center console. It was a digital clock that angled back at the driver/passenger and left a smaller change-holder for storage.

Starting in 1993 Troopers could have optional headlight washers. They had a washer nozzle and a small wiper arm under each headlight and were operated by a separate button on the dash. One push of the button would wash 3 times and wipe 4 times.

Foot rests for backseat passengers was an option in 1992-2002 Troopers. These mounted under the front seats. They were plastic boxes approx 3" tall with tops that angled backward and had a grip molded into the top. These can be removed to provide space for a CD changer or storage for other small things.

Starting in 1998, there was a compass option. The compass mounted over the rear view mirror and showed an 8 position compass, outside temperature, altitude and barometric pressure. The temp sensor was mounted behind the grille on the driver's side. Many trucks were pre-wired for this option. You can pull down the dome light and/or sunroof control panel and look for a second connector.

Technical

"Easter Eggs"

Troopers are pre-drilled for grab-handles on the driver side as well as the passenger side. On 1st gen Troopers there are two holes above the window where a grab handle can be mounted. By feeling through the headliner you can find the holes. 2nd gen Troopers can have two grab handles added. One on the A-Pillar and one above the side window. You'll need to remove and mark the two trim panels for square holes. Some trucks had the backs of the trim panels marked for these holes, but if your's isn't marked you can either eyeball them, measure based on the truck, or remove the passenger side trim panels and use it as a template. A detailed description of how to do this is located at this webpage [1]

Pre 1988 Troopers had their rear speakers mounted in the ceiling. This meant that the speakers weren't blocked when the truck was loaded with cargo. Some (maybe all) 88-91 Troopers had the upper buckets in place above the head-liner, just waiting for speakers. You should be able to see them by removing the dome light and carefully pulling down on the headliner. The pods are above the outside edges of the two rear doors.

Troubleshooting

• 2.6L won't start
  
• 2.6L MAF Cleaning Procedure
  
• 2.6L Timing Belt Procedure
  
• 2.6L MUA5 Bolt Pattern
  
• 2.6L Hose Diagrams
  
• 2.6L Belt Diagram
  
• 2.8L V6 Valve Adjustment
  
• Wheel Bearing Repack
  

Modifications

• Trooper Torsion Bar Re-indexing Procedure
  
• GM 60 Degree V6 Power Tips/Mods
  
• 1st Gen Engine Swaps
  
• 2nd Gen Front Suspension (US market)
  

Tips/Other

• Tire/Rim Size Chart
  
• Increasing Fuel Efficiency
  
• Reading of Custom Essay, Manuals and Instruction about Troopers.

After-market suppliers

When trying to find after-market parts for your Isuzu there is only a few places you can turn to.

One of the best is Independent4x. This is a 4wheel drive shop in Virgina and does a lot to help out the isuzu community. Matt, who owns the shop, is just as big of an Isuzu nut as the rest of us. So if you have any questions call him and he will help you get through them. [ http://www.independent4x.com/]

The next best place to to find parts is Calmini out of california. They have lessened their supply of isuzu stuff in the last few years, but they were still the first company to build parts for our rigs. [ http://www.pureisuzu.com/]

Replacement parts

Replacement parts for our trucks are becoming harder and harder to find, but there are still a few good sources for them.

Jerry Lemond is one great source. Just search his name on the board and you will find his screen name. He is an ex technician trainer for Isuzu. Now that he is retired he buys out stock piles of old Isuzu parts.

Another great source is All Isuzu and Hyundai, This company sells used Isuzu parts. Consider this as a "junkyard" where they pull and inspect the parts before mailing them to you. [ http://allhyundaiisuzuparts.com/]

Related Links

cellulite