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Jeep Grand Cherokee Maintenance and Repair



  • Air goes from cold to a regular blowing temp. What does this mean? Are you getting any warm air at all? Is the blower motor working on all settings? As for the fumes, this sound like you have a coolant blockage at or near your heater core. The cheap way of possibly fixing this problem, is to get the cooling system flushed. You can have this professionally done, or do it yourself. I myself do my own.
    Try this: you can go and get an off the shelf bottle of coolant flush and use as directed which probably will fix your problem (fingers crossed). Or you can try this: drain the system of coolant. Take the thermostat out and refill the system with water. Add dishwasher washing crystals to the radiator (about 4 cups). The crystals act like sandpaper and blast away the built up crud from years non- preventive maintainence.
    Drain the system from the lower radiator hose, refill with water, let run for awhile and drain again.Repeat as needed until most or all of the crystals have left your cooling system.Replace your thermostat with a new one (while your at this stage anyways) and refill with a 50/50 mix of prestone coolant and water.
    I hope this helps you, and good luck m8.
  • The shaking your getting is more than likely the fact that you re-installed your front drive shaft 180 degrees from it's original position. Also inspect the drive shaft to see if any of the small balance weights have knocked off recently. Are the universal joints in good condition, and no parts missing? Most shaking in the front end can be attributed to lost tire balance weights, mud or dirt on the inside of the tires, separated or worn tires, unbalanced front drive shaft or a worn front end dampener shock.

    I hope this helps you, and good luck m8.
  • tuggajbtuggajb Posts: 646
    if you replace the ring gear you also have to replace pinion gear as these are matched sets
  • The pinion does not have to be replaced if your replacing the gear nest with the original gear ratio. If your swapping out gear ratios ie: 373 ratio to a 410 ratio, then yes, everything must be changed to match each other.
    The diff in your particular year is more than likely a spicer35 in the front, and a spicer 30 in the rear. These are the most common setups in jeep products. Talk to any gear centers, or driveline centers in your area about replacing the gear nest in your diff.
    By the way, i've replaced 20+ gear nests over the years, and never had to replace the pinion; unless the pinion was damaged, or needed replacing.

    I hope this helps you, and good luck m8.
  • I hope you got your tranny fixed, but if not then.....
    I cannot see internal transmission failure, because you state that in fact there is smooth gear transitioning. I assume that other than using more fuel to get you where you want to go everything else is fine regarding the transmission. There is a governor sensor located inside the transmission pan, and that needs to be changed. I would have a compentent shop or dealership do the work, (it really is messy work), and since your at the point, changing your transmission filter is a very good idea (about $30 ). A good idea for the first 2 weeks after the fix, is to put cardboard on the ground under the transmission. Or just keep an eye on it. Transmission pans have a tendency to leak from the bolts loosening off, and will need to be re-torqued to spec, unless you ask them to use lock-tite on the bolts.

    I hope this helps you, and good luck m8.
  • if your fan works with the air on and your problem is no heat then it is the flaps in the blower housing that are not directing hot air into the cabin. had the same problem and i went to this forum and was directed to a company called heater treater. they sell a product that is specifically made for this problem. was easy to do and only took 45 min and cost $145 heater has been working great since, it comes with full idiot proof instructions, hope this helps.
  • Start engine--run til hot--feel the two heater hoses near where the enter the firewall connections. If both are equally hot the water is circulating thru the heater core.
    Kill engine.Drop the golve box lid all the way down. You will need to release the rubber stops and flex the two pins on the top of the lid so that it will come all the way down.
    At the left side you will see a squarish black box attached to the blower housing.Remove the two srews holding it. Lift the housing away from the blower house(leave wireing connected). Pay attention to the shaft alignment. Turn the switch on. Set air to floor. Manipulate the heat control. If the shaft ring does not move within the motor housing do this. remove the 4 screws on the housing. Slowly lift the side off to expose the gears. Remove the three regular gears to expose the worm gear.Again manupilate the heat control. If the worm gear does not move.---Remove the tiny motor and turn the screw by hand to free it up. Again see if the motor will run. If it runs--- replace everthing. Reattach the motor housing to the blower housing and try it out again. That fixed my problem at no cost--just time and frustration Good luck--Smokey Swann---Tx
  • I have a 1995 Grand Cherokee w/ EFI, 5.2, quadratrac.
    I drove it approximately 30 miles today and it ran fine but when I took a lefthand turn three blocks from my house it just died. I tried to start it and I get the starter turning but it won't turn over.
    I thought it might be the fuel filter so I let it sit for about an hour thinking that if it was clogged the sediment might settle but got the same result.
    Any suggestions?
  • Did the engine turn over? Was voltage near 12 with the key on? If the engine turned with the starter but the volts were below about 10, you may not be getting ignition, and fuel might also be a factor if voltage is low. Sorry I can't tell you for sure what to poke at.

    Anyway, at least you were close to home. Merry Christmas.

  • The engine does not turn over and I just replaced the battery two days ago.
  • Hello, I am trying to install a different bolt pattern rims to my Jeep, so I get a set of wheel adapters on the internet, but the wheels get lock with the adapters on it and is impossible to move any wheel by hand and not even trying driving the car, the size on the adapters are fine, everything fit perfectly and I don't see any reason to what is happening. Is any wheel sensor locking the brake system?
    Has anybody seen this before or any possible suggestion?

    Thank you
  • Ouch. I'd say, start by making sure you have good batt connections. Then, it's probably the starter and/or solenoid for the starter that's sapping your batt. If you've tried to jump the Jeep unsuccessfully, I'd put money on the starter assembly. If it jumped OK, I'd sat batt cables are a guilty party.
  • I am the proud owned of a 1999 Jeep Grand Cherokee Laredo 4x4 4.0L.

    Two days ago after cutting my jeep off I noticed the fan running.. I know it is normal but it remained on after 1 hour.. So i unplugged it by the radiator.. 45 mins. or so later i plugged it back in to see if it would still be on and it stayed off. On the drive home I noticed that I was starting to overheat at idle.. Checked when temp was high and fan was not on..

    Changed Coolant temp sensor
    checked fuses.
    cant locate fan relay..
    a/c works and fan doesn't come on
    fan is working when I jumped it to battery.

    Can anyone help diagnose this problem.. Please.

    I have a 260 amp alt- 3 batts, and 6000 watts on 2-18's This is a daily driver and Competition vehicle. I do not want to overheat and ruin the motor. (not a fan of the 4.0L but it is what I have)
    I do all the wiring on my Car Audio and have decent knowledge of 12volt systems.. I was a mechanic years ago but changed jobs due to eye injury.. So I have some knowledge of automotive trouble shooting and diagnostics. II need advise from someone who knows this specific vehicle.. Any help would be appreciated.

    If anyone has questions about car audio/jeeps i would be glad to assist as well.
  • Sounds like the fan controller module is dead. One of our Jeeps has done the same thing. As a fast fix, we rigged the fan to be on when the lights are on. This fix may also work for you as well, but it is a temporary fix.
  • There are usually at least 2 temp sensors. One talks to the fan relay to run the fan when needed. The other one talks to the computer. Is it possible you changed the computer input sensor? They usually look similar. I have a V8 so am not able to describe the location of the probable guilty part on your 4.0 and I'm 5000 miles from my service manual.

    With electical power on, grounding the electrical connection to the correct sensor should fire up the fan. If I'm wrong about this one, someboby please chime in.

    Happy New Year --- Clip
  • my 1996 jeep is doing the same thing. the head lights are flickering when driving or shut off sitting
  • 1996 cherokee jeeps head lights are just flickering. when im driving or when its shut off if anyone konws whats going on id like to have you in put cuz im stuck. email me at if you have something
  • Hey there,

    I have a friend who JUST paid off his 99 JGC and EVERYTHING is going on it. It seems like a money pit and I told him that. I'd like to hear from others.

    He has a rear wheel seal and bearing that is going out. It is leaking all over the place. He also had the Pitman gear box that goes through a pint of fluid every 20 miles. Warped brake rotors, and a slew of other little problems that are going to add up.

    He can not afford another vehicle, nor can he afford the repairs. I think he should sell it and get what he can for it and get something else. What do you all think.
  • Hey i had the same problem with my jeep. I have an 2000 Grand Cherokee I-6
    I was having the same problems the fan would stay on( but i just re-started it and it turned off) and the lights would dim, it would over heat in slow driving or when stopped, and it would hesitate turning on. turns out my fan motor had died and the car was trying to cool its self and the battery and alternator were fine i just over worked them. I had to replace the entire fan assembly and a new battery it cost a pretty penny and took sometime but it worked. There was a recall on my fan assembly that was checked out by a dealership in Florida and they said everything was fine back then and sense they checked it out my local Jeep dealership said there was nothing they could do. but good luck! Jeeps are awesome the mechanic said that he was surprised that it went so long (5 weeks :))
  • I haven't had a chance to work on the problem yet due to my work schedule and the weather.
    I do have another question though, the starter runs but the engine doesn't engage.
    I tried hitting on the starter with a mallet to see if it might be locked up but that proved useless.
    I guess I'm questioning the bad starter because I didn't think that if it just stalled when I turned a corner that a bad starter could cause it to stall? Can a bad starter cause problems when the vehichle is already running?
    Needless to say I'm not a mechanic so if my question seems dumb I apologize!
    Thanks again.
  • Wow. Sounds like you may be into more than one glitch or some truly serious electric gremlin. I fear the days of bashing the starter are kinda' over, although I'd have done it too just 'cause I have a big hammer and I'm old.

    As to why it quit? No guess. As to the starter situation, I'd say a remann'ed starter assembly is just about a must.

    Happy New Year --- Clip
  • Does the starter engage or do you have zero/nothing?

    My 97 would kill and I would have zero power; no radio, starter, lights, etc. If I moved the tilt wheel up and down, the power would come back on. The issue was a short in the ignition wiring. I pulled the cover off the steering column, repaired the contacts and made sure there were no bare wires. That was 20k miles ago and no problems since.
  • It was -20 degrees this morning. My Jeep has a great heater except on the passenger side floor where it remains -20? Nobody will ride with me in the winter.
    Has anyone else had this problem? How about solutions?
  • Thanks for all the great ideas but merely by accident I solved the mystery.
    It was a slight crack in the coil wire which contacted metal when I turned the corner and was shorting out the system. I replaced the wire and we're on the road again.
    Very lucky find!!!
    Thanks again to everyone that gave ideas.
  • trickstertrickster Posts: 113
    Clip is correct. There are 2 temp sensors, one for the fans, and one for the temp gauge. Disconnect 1 at a time to find out which is which. The fan sensor will be obvious, because the fans will start when you unplug the sensor. You can also try, the cooling fan relays, located in the power distribution center that is under your hood.(these usually house all the maxi fuses and relays). I find that the cooling fan relay is identical to another relay(s) and i swap them around to see if i have a faulty relay.

    I hope this helps you, and good luck m8 :)
  • Just wondering if you got this figured out?? I am having the very same problem with my 03' and it's starting to get cold.. It's like it work's when it want's too. Thank's so much.. :confuse:
  • Winter is here and my heater is acting funny. I have a 2003 Jeep Grand Cherokee and sometimes the heat comes on after 30min and sometimes it takes cranking my Jeep up several times or more before it will work. Had the thermostat changed, heater coil flushed and bought new control panel. This is driving me crazy. Any suggestions?? Thank's sooo much.... :confuse:
  • ellachellach Posts: 8
    I have a 2003 grand cherokee 2.7 TD. i am getting a misfire/ rough idleshe appears to run okay once i am moving any advice ?
    Regards Ellach2
  • i have a 2002 jgc overland it fires up and then immediatley stalls. i have to hold the gas to keep it running untill it will idle itself.most of the time it is on cold mornings or after it has sat for a few hours.also when i make a turn it sounds like something is coming apart in the rearend (it is a quadtrac). any hints or ideas would be greatly appreciated.thanks,freddy p.s. battery gauge bounces back and forth when i have the atarting issue until it gets driven a mile or so.
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