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Isuzu Trooper



  • 2001 Trooper, 40,800 orig miles, first owner. No problems to date.

    Recently tried to engage shift-on-fly 4x4 but it would not engage. Dash light blinks normally but front wheels do not kick in and dash light just blinks until I give up and turn off shift-on-fly switch.

    No odd noises whatsoever, drives perfectly in 2-wheel drive.

    Have tried to engage 4x4 from dead stop, low speed, 60 mph, but no go. 4x4 has worked perfectly before, this problem just began with the first snowfall. (Typical!)

    What else could I try? :sick:
  • atfdmikeatfdmike Posts: 414
    It sounds like your vacuum operated actuator on the front axle is not working properly. It is attached to the front axle and when 4WD is applied it actuates the spline coupler to lock the front axle into proper mode. You can at least check to see if vacuum is applied when you shift into 4WD by checking the vacuum lines at the actuator. It is not uncommon for these actuators to stick.....the 4WD should be engaged periodically even when not needed to keep these parts working properly. One guys opinion. good luck
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  • This sounds like a great place to start...

    Question 1: How do I check for vacuum at the actuator? (Engine off/on? Tranny in park or not? etc. Don't want to run over myself.)

    Question 2: How can I "wiggle the actuator free" if it is 'stuck'.?

    Question 3: Where does the other end of the vacuum hose attach? I'd like to check both ends to make sure they are attached properly. Is it possible it might have been knocked off during pressure washing engine bay?

    Thanks for your help. Wes.
  • atfdmikeatfdmike Posts: 414
    Very briefly, need a vacuum source (engine running), park....remember you are just checking to see if vacuum is getting to axle from t-case. Once you establish that vacuum is present and switching with your interior switch, then move on to repair.
    Wiggling as you call it is a little more interesting.
    Go to, enter your vehicle info, then find Illustration figure 4-12, second image. It shows the axle assembly schematic. Before attempting to remove the actuator, I would definitely drive the vehicle long enough to warm it up and repeatedly try to cycle the SOTF system (after completing Question 1and finding the vacuum switching with the switch...I don't know which port has to have vacuum to work right, but obviously it should change when you cycle the switch.)).
    The t case has an electic shift motor and a module sits atop the case where the vacuum is switched by the shifting tcase. If you search you can also identify it. You would want to work your way back to the vacuum source on the engine too....I don't know your motor but I think you should be getting the gist of this.
    The electric switch on the axle actuator is just to turn on or alert the driver and 4WD system as to the status of the axle, it does no other function.
    Also, If you have TOD system, I know even less about that except it can be hard to troubleshoot. Good luck.
  • ddahzddahz Posts: 1
    purchased a 99 trooper w/ 101,000 miles on it about 6 months ago. I had to replace the intake man. gaskets to get it to idle and run correctly. now i would like to get some decent gas mileage. i love the vehicle (its the luxury mod. w/ all the toys) and it does real well in the snow, but i can't live with 10-11 miles per gallon. any ideas on how to get that up to 18-19 mpg? computor chip, o2 sensors, different injectors, new plugs? Thanks in advance
  • domo1domo1 Posts: 1
    when heatis on no wam air is coming out have replaced the thermastat to no avail was told it could be the heater core but can not find the part to buy is there anyway the old one can be worked on to still be able to use it
  • I didn't see what year your Trooper is. I had a 1990 with same problem.

    Like you, I did some things to TRY to solve the problem...engine flush, rad flush, new thermostat...nothing worked.

    It turned out that the problem was with the valve that routes hot water from the engine through the heater core. Hot water was not getting into the heater core at all, so of course no heat would come out into the passenger compartment.

    I can't recall if the valve was actually built into the heater core or if it could be replaced separately, but pull out the heater core and have a look at that valve...I bet that's your problem.
  • atfdmikeatfdmike Posts: 414
    I suggest you eliminate the basic causes of poor mileage......check your tire pressures and regular maintenance items. The plugs may help, but there is no realistic way to raise mileage above the rated MPG from the manufacturer. IF your O2 sensors are bad, then that would cause your ecm to run in the cold mode and enrich the fuel mixture.....not good for mileage. I guess you would have to use your best judgement OR have a technician check the vehicle while operating with the proper Tech2 OBD to make sure it is performing correctly. One guys opinion.
    Good luck.
  • I have dropped the Pan and drained the ATF but the resevour has not emptied out. Also where do I put the ATF fluid back in to fill it up?
  • atfdmikeatfdmike Posts: 414
    Whoaaa.....we need a little more info on what year, model , engine and type of transmission or system you are working on. Once that is posted I am sure you will get some good replies.
  • Under 50K miles - yup. 2WD model. By the time I noticed fluid on the driveway and figured out it was the Trooper, it was too late. Leak found and fixed but the trans was gone - only had 1st and 2nd gear and it was not happy. Long story short, excellent rebuild by Gold Coast Transmissions in Ft. Lauderdale (top notch) so try these guys if you have to. Fuh-ortunately, my mechanical breakdown insurance covered the extensive cost minus deductible. Isuzu's only response (what's left of the dealers) was to inspect and if they felt like it, replace the whole unit under warranty (maybe) - (some mechanic who only knows how to unbolt and bolt on a tranny.) So ... watch the fluid leaks friends. If you need a picnic spot, you can eat off the floors at Gold Coast. Really impressive.
  • Were there any other symptoms of the transmission problem aside from the fluid leak? And where was the leak itself?
    I also have a 2WD 2002 under 50k in South Florida. The only transmission issue I have noticed so far is a small clunk going from Park to Drive or vice versa. Gearshifts seem fine.
    Was thinking of having it checked out (recall the old AAMCO ads), and will run it by Gold Coast - anyone there in particular?
  • matausmataus Posts: 43
    I really hope someone can help me. I ran into a situation today with my 1990 Isuzu Trooper 5 speed manual. With a 2.8 liter V6.

    Today I stopped to wash my car at the car wash. After I did so, I jumped on the hiway. About a miles down the freeway, My vehicle stalled. On the side of the freeway, I went thru the process of problem solving the situation. This is what I had done....

    First and foremost, I checked the distributor and router for moisture. In doing so, I found no moisture. I then checked all the plug wires, and everything was secure and dry. After that, I went ahead and checked to see if I had blown a fuse. In doing so, nothing was blown. I also checked the fabric wire fuses and rearanged the relays next to the fuses. Then I started to think that there was fule pump problem. I went ahead and put some fuel in the carb from a gas can I always keep for safety purposes. I added not too much and not to little. In craking it over, nothing fired. It just turned over. So then I got thinking, maybe my coil was shot. I went ahead and purchased a new one at the auto store and replaced the old one. To all avail, It still woudn't fire up. All it's doing is turning over. In the end, I ended up having to have it towed home.

    So here I am, and I just don't know what to make of it all. When I look back to what I did at the car wash. I didn't open the hood this time to wash down the engine, so I don't know how water could have got anywhere. One thing I did do was spray under the engine and the under carrage. I always do so here in Colorado. Esspecially when the snow and mud collects underneeth.

    If there is anyone out there that can help me troublshoot this problem, It would be soooo greatly appreciated....

    Thanks a bunch....;)

    Maddy :confuse:

  • tidestertidester Posts: 10,110
    Did you check the coils, battery and ground connections or sensors? You could be shorting out some of the sensors giving false reading that prevent the car from running.

    Anyone else have ideas?

    tidester, host
    SUVs and Smart Shopper
  • Hi again... I found the drawings you mentioned...very helpful, thank you!

    UPDATE: I have not crawled under the beast yet, HOWEVER, yesterday when I started up and drove away, I noticed the 4x4 was fully engaged! (Dash light was fully on, traction on ice was obvious.) I switched 4x4 OFF while driving and tried to engage in again, but it did not. This has happened twice...4x4 will engage from a cold start. I tried a few things like putting in park, hit dash switch and drive off, but no 4x4. Engaging in reverse, no. Hitting button multiple times, no.

    What do you think of this, and what else do you think I should try?

    Also, this is an '01 with under 50,000 miles. Do you think a warranty applies?

    Thanks. Wes
  • atfdmikeatfdmike Posts: 414
    Hi, I don't know a bit about warranties, so you would have to contact a dealer or find another owner who might know.
    I don't have your year or type of front axle, but to make a guess on what you describe, I would ask a couple more questions. When you hit the 4X button, do you hear the transfer case shifting in and out of 4X? You can listen with the vehicle sitting still, it does not have to be moving to shift. The electic shift motor should cycle or attempt to when you hit the button.
    If you hear the transfer working consistently, then I would next check the vacuum being applied to the axle.
    It could be that after sitting, the vacuum is gone and on start up, and if the vehicle is in 4X then the axle shift actuator is reacting to that command and does not have to overcome the vacuum that pulls the axle out of engagement. IOW somewhere there may be a sticking valve. It could be the one on the trans case that reacts to the trans case shifting into 4H or 4LO and sends vacuum to one side of the actuator. I am not that familiar with the actuator system, so I don't know if the actuator is spring loaded one way or the other or whether vacuum in the other direction is needed. I would research that a little more, by carefully looking at the axle actuator and pulling the vacuum hoses while the transfer case is shifted into different positions. You should be able to determine what is happening (or not). Remember that to be safe, park on level surface (or ramp) with park brake on and chock the rear wheels at least. You don't have to have the vehicle in drive to operate the transfer case and thus the axle. Vacuum should at least be present or not depending on the button position. Listen before doing anything for vacuum leaks. Have someone you trust shut off the engine while you are listening down there to hear if you hear a leak as might be present.
    I am no expert,but I think this will cover the basic things. Be careful if you elect to do it, good luck
    These are pretty easy things to check first in the event you don't have warranty coverage.
  • renet10renet10 Posts: 13
    I have replace the alternator belt 2 times. I still get the squeal. :mad: I tighten and tighten but still the squeal. :mad: The last belt broke. Is there anything else that controls the tension of the alternator belt that will eliminate the squeal and get my amps up? :sick:
  • The belt might fail prematurely if over tightened.
    Are you having a problem getting enough amps from your alternator? The belt squealing sounds like the alternator, if working properly, is making a lot of amps which is why it is hard to turn. Maybe you have a short circuit or too many loads (120Vac inverter running something big?) demanding excessive current. If you want lots more current there are after market alternators that can be made to fit that can produce 200Amps maybe more, some can act as a welder too.
    It could be excessive mechanical friction preventing the alternator from turning freely, that would make the alternator body hot.
    It could be not enough friction on your pulley. If the pulley is worn out or coming apart then the belt might not fit securely and that could make it slip. If this is the case the slipping pulley will be hot.
  • atfdmikeatfdmike Posts: 414
    Are you sure it is alternator? Reason I ask is Power Steering is right above and sound you hear could be that? . Also I would check the V grooves on the crankshaft...they may be full of melted belt which will have to be removed in order to get the proper friction. I have seen this on the AC belt as well.If not, you may have bearing in fan going.
    Hope this helps. Good luck.
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