Need Diagnostic Help

    It seems like everything with both my Jeeps wants to break all at once... Unfortunately I'm not a mechanic by any means and I need some help figuring out what needs to be done...


    Vehicle : 1992 Jeep Wrangler (4 Cylinder)


    Problem # 1 : Shuttering/Heavy Vibration over 40-50 MPH.


    This problem started about two to three months ago, about three months after I bought the vehicle. Today it has gotten a lot worse. Basically, when traveling at 40-50 MPH or higher, the vehicle starts to vibrate violently in a pulsing manner. I can feel it start in the bottom of my seat and work its way up the back and then start over. A friend of mine noted that the "vacuum disconnect" on my front axle was disabled and therefore my front drive shaft is spinning all the time. I've gotten hints that it could be either the front drive shaft and therefore replace with a Tom Woods to match my rear or that it could be another component of the front drive train... Any ideas?


    Problem # 2 : No Temperature Read Out


    My Temperature Gauge, when I purchase the vehicle, would bounce all around. Now it's stuck at the lowest number and not moving. What's the most common reason for this?


    Problem # 3 : Red Fluid from Transfer Case...


    What's that going to require to fix?


    Concern # 4 : Header Discolored


    This could be no big deal, but I thought worth mentioning since I have no clue what, if anything, it means... About a month ago I had a PaceSetter Header installed to replace the cracked stock one (provided by the seller). It was power coated black. I noticed today it's all burnt up looking, with little to no blackness too it at all... Is this normal or is it getting entirely way too hot?


    Any and all help is greatly appreciated. Sorry if I don't provide as much detail as I could or if some of the questions I asked are moronic. Thanks.

    1. Remove the front drive shaft and take it for a drive. That will help isolate your vibration.


    2: Could be a bad gauge, a bad sender, or a bad connection between the two.


    3. Depends where it's leaking from. Clean it up good and try to locate the source, I would start at the rear where the drive shaft connects.


    4. If they were really powder coated, I'd wonder about who you bought them from. If they were ceramic coated that's a different process. But it depends on the quality of the coating

    Thanks for the rely. I did some research and determined the PaceSetter Header I have was simply "painted black" and was not coated with anything special to prevent discoloration. I'll drop the drive shaft, clean up the under carriage and give it a drive to see what the issues are. Thanks again!

    Problem 1 could be an unbalanced tire. You could have had a weight fall off.

    Member since 2000

    Jeeps Owned'79 CJ5:

    Specs-

    - 258 I6

    - '93 Cherokee fuel injection and HO head,

    - bored 30 over

    - with 4x4 cam

    T18 tranny with granny low / Dana 18 t-case

    Dana 44 front and back from late '70s Wagoneer, both locked and loaded with 4.88 gears

    SOA on modified YJ springs with shackle reversa

    Fiberglass tub with 6 point cage mounted to the frame


    2015 Grand Cherokee Limited
    Spec-

    Quadratec Floor mats

    Possible, but I doubt it. The vibration, which I forgot to mention, only occurs when in gear and accelerating... In neutral or in 3rd / 4th Gear without the foot on the accelerator, the vibration is gone.

    I would normally say that's a drive shaft U-joint going bad but since it's only happening above 40 mph I'm questioning that. I'd definately start there though.


    At the higher speeds you'll be in a higher gear which means less torque and less tendancey to rotate the pinion upward under normal load. Accelerating will cause more torque to rotate the pinion up. Even though it only goes up a few degrees, it could be pushing a worn U-joint out of alignment enough to cause the vibration.


    An un-balanced tire will cause the vibrations over a certain speed but it wouldn't be dependent on whether or not you were accelerating or coasting.

    Member since 2000

    Jeeps Owned'79 CJ5:

    Specs-

    - 258 I6

    - '93 Cherokee fuel injection and HO head,

    - bored 30 over

    - with 4x4 cam

    T18 tranny with granny low / Dana 18 t-case

    Dana 44 front and back from late '70s Wagoneer, both locked and loaded with 4.88 gears

    SOA on modified YJ springs with shackle reversa

    Fiberglass tub with 6 point cage mounted to the frame


    2015 Grand Cherokee Limited
    Spec-

    Quadratec Floor mats

    While you are pulling the front ds pull the rear too and check the joints. I am betting one of them is bad and causing the vibe which is causing the rear output seal of the t-case to loose fluid. If this is the case change the seal on the t-case when you fix the ds. Also don't forget to check the t-case fluid level, low fluid can cause complete failure of the t-case.


    Aaron

    Thanks for the suggestions; I should have access to a shop by the end of the week/early next week. I'll make sure to try all of that to pin-point the problem. Maybe my rear DS is the problem for both the vibration and the leaking.

    No need for further diagnosis! After extensive testing and research (leaving work today :D ) my Rear Driveshaft disconnected. After looking at it, best I can tell is the rear U-Joint Failed and took with it part of the Pinion Yoke. So... Guess I need to look at it further in the day time, ensure no damage was done to the Driveshaft itself and order the new parts... At least I know what the problem is now!

    The broken parts for your AWARD wall of course.

    Member since 2000

    Jeeps Owned'79 CJ5:

    Specs-

    - 258 I6

    - '93 Cherokee fuel injection and HO head,

    - bored 30 over

    - with 4x4 cam

    T18 tranny with granny low / Dana 18 t-case

    Dana 44 front and back from late '70s Wagoneer, both locked and loaded with 4.88 gears

    SOA on modified YJ springs with shackle reversa

    Fiberglass tub with 6 point cage mounted to the frame


    2015 Grand Cherokee Limited
    Spec-

    Quadratec Floor mats

    Also, on another note, I noticed that immediately after the incident with the drive shaft occurred a lot of Power Steering Fluid had escaped out of the fill port. Would this have been caused by pushing the Jeep while it's off and turning the steering wheel or is it completely unrelated and a horrible coincidence?

    Having grease fittings only helps if they are used.



    I would go with the non-greasable triple sealed.



    If the slip joint fits together more than one way, make sure you get the yokes in phase, or the new u-joints won't last long.


    So I've come to the conclusion based on some input from my mechanic that I really should only need a new U-Joint & Yoke Strap/Bolt Kit. Question being, based on the fact that it's a Dana 44, which exact U-Joint should I get? Also, what Yoke Strap/Bolt Kit? I can't seem to find what I'm looking for on Quadratec (most likely because of my limited experience). If I can get it figured out today, order tonight I can have them in time for the weekend to fix up.

    Thanks! You're a life saver. Those were the items I looked at, but wasn't sure if they'd work with the 44. Would the U-Joint be the same if I were to replace the rest?

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