Announcement

Collapse
No announcement yet.

tranny noise

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • tranny noise

    Why might I have a loud thrashing noise coming from the transmission area that starts at 40 mph? It will even thrash when coasting down a big hill as long as I am going over 40 mph. I had noise at slow speed when I first got the M1161 that was due to the bent skid plate. I removed the skid plate that was rubbing front drive shaft that looked undamaged and that low speed rubbing noise was gone.

  • #2
    I am not a mechanic so take my suggestions with a grain of salt LOL.

    I would check to make sure you are truly in 2 wheel drive and not 4 wheel drive. The front differential gets very noisy at higher speeds in 4WD. You can also check your U-joints. Loose ones tend to make a lot of noise when coasting even if they are quiet under power due to the backlash.

    An easy way to test if you are stuck in 4WD is put your front tires on a curb and slowly try to crawl over it. If you are in 2 wheel drive, likely the rear wheels will spin where in 4 wheel drive you will crawl over. You can check the theory by trying in 4 wheel drive vs 2WD.

    The last thing I noticed on ours, everything gets loud at 40mph and higher due to all the rattles. The Lifting Rings and Tiedown Rings all rattle like crazy in the wind. Also the winch and pulley rattle around in the wind. We ziptied all the rings and loose parts on one of ours and it was amazing how much quieter the vehicle got.

    Good luck and hopefully it is something simple and not an actual transmission or drive train issue.

    AR

    Comment


    • #3
      I had a couple of odd noises that were quieted after full maintenance. Use the TM manual to be sure you covered all of the lube and fluid check points. I thought my transfer case was having new issues (one of them similar to yours), and it turned-out to be a U-joint. Whew.😅 Don't forget the slip joints. 6 lube points on the shafts just for those two items, and they need regular attention.

      Trans fluid, transfer case fluid, differentials, etc. It can be tough to find noises, as the sound travels through the structure. Worst-case, put it on a shop lift, dismount the tires, and rotate the driveline. Lots of driveline checks and tests online to follow so you don't have to guess. Good luck and let us know what you find!

      Comment


      • #4
        I have a growling noise coming up through the transmission tunnel at 40mph. I greased the slip joints on driveshaft but there are no grease fittings on ujoints. U joints look great and tight.

        any thoughts? My skid plates were bent by gov planet on load up, but no damage to drive shafts.

        Comment


        • #5
          Just a reminder that the outer appearance of most parts does not relate to the inner or functional condition.😉 As a first-step, I would (carefully) check after a drive for any joints or parts that are unusually warm.

          Original and most off-road U-joints have grease fittings to ease maintenance, and allow flushing of any water intrusion from water fording or standard-procedure pressure washing of the driveline in service. If somehow your joints are original or old, the grease is likely dry and caked, requiring disassembly for service, inspection and re-greasing.

          My first ITV had one bad joint at under 500 miles, even with original Zerk (grease) fittings, and all of them and the slip joints were dry. I had to temporarily plug the vent holes on the slip yokes to force old dry crap out and get new grease into the splines, or it would have continued to run dry after "normal" greasing. I can say for certain that most of the TM-required maintenance was never done on some of these vehicles. Good luck to all of us!

          PS: This is just joints so far. I'd be checking the transfer case fluid level, bolt torques, and condition along with other maintenance points where possible. I bought a lighted fiber-optic 8mm camera to plug into my smart phone (online under $10) that helps me see in tight spots, cases and holes. Mirrors help too.
          Last edited by W427; 10-10-2020, 10:18 AM.

          Comment


          • #6
            Thank you. Here is an update. Ujoint on front drive shaft at transfer case felt warm.
            pulled driveshaft.
            drove growler.
            sounded great, no more noise.
            bought new ujoint with grease fitting moog 369
            installed ujoint and shaft
            test drove.
            noise is still there
            put it in 4 wheel drive, noise is quite on acceleration and louder on deceleration.
            driveshaft flange was scrapping the skid plate for about 100 feet when I first bought it and pulled off trailer. Driveshaft flange end only. No visible damage beyond a paint scrape.

            growler has 900 miles. Transfer case fluid full and clean.

            possible issues? Transfer case or bent driveshaft.

            I need more suggestions. Someone else has had this noise. Need to know if I should send out driveshaft or start looking at transfer case.

            Comment


            • #7

              Comment


              • #8
                I have personally seen 3 bent front driveshafts from the rocket scientist at Govplanet.
                I also worked on one Growler that had no gear oil in either differential.

                Comment


                • #9
                  Ras1 Dave, For what its worth - when we were working on a mates growler it made a bad scraping grinding sound on deceleration, turned out to be bottom rear of transfer case scraping/rubbing on bent skid. As you slowed down the rubber mounts and reverse torque allowed the transfer case to drop and rub on the plate, and hugely amplify the drive train sounds. It didn't help that the marines had busted the rear driveshaft, and when the new one was installed, they left the old flange in place against the transfer case. They simply fitted the new driveshaft flange against the old broken weld face!. We straightened skid plate and refitted driveshaft without "spare" flange and problem gone. Maybe check for rubbing marks on transfer case - not much clearance there. I guess it will take 1 - 2 years for us to "fix" all the gremlins on our growlers. Good luck
                  Paul
                  Skyhawk

                  Comment


                  • #10
                    Hmmm. Interesting. Maybe I start by pulling the skid plate off again.

                    thanks
                    dave

                    Comment


                    • #11
                      Originally posted by Rasmusrentals View Post
                      I have personally seen 3 bent front driveshafts from the rocket scientist at Govplanet.
                      I also worked on one Growler that had no gear oil in either differential.
                      I agree. Most are bent from poor load up procedures at gov planet. However I guess we are lucky they will help load at all, or we would have to pickup every load ourselves with a winch or tow truck.

                      my diff fluid was a bit low. But I checked and changed all fluids before first test drive.

                      I'm hoping the skid plate is touching somewhere, but it seemed like along with the growling noise I had vibration, and it seems strange that the noise and vibration is gone when front driveshaft is off, and changes in noise level when front shaft is installed and I run it in 4x4 high.

                      Comment


                      • #12
                        While crossing fingers that it's an easy interference issue; possibility due to the lift and rubbing damage at the yoke can also be transfer case output bearing damage, output shaft damage, or case damage. A quick inspection of the output area and for any play in the output may reveal something. While inspecting everything else, pry moderately against the output in multiple directions or firmly shake two-handed. Same for the differential inputs. The up-side, if it is in there, is that transfer cases are not horribly complicated to service. Your NP241OR unit should otherwise be too fresh to need any additional rebuilding.

                        Click image for larger version

Name:	NP241_diagram.jpg
Views:	240
Size:	120.8 KB
ID:	4802

                        Comment


                        • #13
                          Thank you. I checked skid plates again. Plenty of clearance, nothing is hitting or rubbing on any transfer case, transmission, driveshaft.

                          the output flange on transfer case spins freely, and I dont feel any end play. Now, the output flange and u joint were a bit hot after 50 mile test run. When I pulled u joint caps off, they looked ok, but I think it smelled burnt. I attributed the warm output flange to the u joint.


                          maybe with only 900 miles the problem has not had enough time to really show up. However I was nervous to get home after 50 miles with the noise. I would not drive any vehicle with that noise. With the front driveshaft off, I have no worries driving.


                          Dave
                          Last edited by Ras1; 10-11-2020, 07:54 AM.

                          Comment


                          • #14
                            Ras1 Dave is there any chance it is “locked” in 4wd even though lever shows 2wd? Not even sure it’s possible with this model Transfer case. Just a thought.....
                            Skyhawk

                            Comment


                            • #15
                              Originally posted by M1163 View Post
                              Ras1 Dave is there any chance it is “locked” in 4wd even though lever shows 2wd? Not even sure it’s possible with this model Transfer case. Just a thought.....
                              No. Flange spins freely with driveshaft removed

                              Comment

                              Working...
                              X