Novak Conversions Jeep Wrangler TJ engine mounts

2004 4.0 42RLE: grinding vibration noise on very cold temp start-up

Buckz6319

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Original poster
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Oct 16, 2024
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69
Location
Pike County, GA
1st short video was recorded a while back when it was on a extremely cold morning here in GA ( unusually cold for during winter months)




2nd short video was recorded this morning 2/15/25 - not very cold this on start up ..just misty rain and probably about 45°


Now…I have been having a vibration/grinding noise for a while. The vibration/grinding noise is a rotational issue.

It is felt ( besides hearing what I have recorded on video) then I put in drive ( jeep is on pavement) at idle..(no gas pedal being used at this time) just engine rpm and transmission moving Jeep forward..very slow..I can feel that moving forward slow at idle rpm..like I have a flat spot or two on a bearing, however it continues as speed increases and I can feel vibration/grinding at any speed above about 20 mph..in the front tub area, front seats and when I put my hand on very top of front right/left headrests.i feel the vibration/grinding there ( kinda weird). I also can feel it while driving and put transmission in “ N “ and when coming to a complete stop..I feel and hear ( I’ll try to describe) a different vibration/grinding sound ( kinda weird also).

I have had all wheel bearings replaced, including rear axle bearings. I have had a rear differential total rebuild professionally by a local business that’s been in business for over 50 years. The owner of the business was the one who actually did the work himself. He’s a great guy and has a lot of knowledge been working on jeeps for more than 50 years.

Once I received the Jeep back from the mechanic shop, I put the triple meter back to 0 so I can keep track of how many miles is actually on the newly totally 100% rebuilt rear differential which included new axles also they were badly damaged too.

I have been back to the shop several times with this issue that I’m having and the mechanic who did the work thinks it could be an issue with the type of tires that I have on this Jeep Which have big lugs kind of more of a muddying type tire. The mechanic also told me that he wanted me to take him for a ride and I did and it’s really hard to pinpoint exactly where this issue is coming from and that’s why he still thinks but not 100% sure that it could be the tires.

In my personal opinion since I drive this Jeep every day of the week 3 to 500 miles a week that this issue is possibly coming from somewhere else other than the tires. I’m starting to wonder if it is something in the automatic transmission or in the transfer case or front card an joint or transmission, torque converter, or output shaft bearing… the owner of the shop, checked everything out really good and said you joints were tight. He checked fluid in the transfer case checked to other items also while he had it there to shop doing a total rear differential rebuild.

Right now, I can say that driving this Jeep with the vibration and the grinding issue is driving me nuts and I’m hoping to figure out where this issue is coming from and get it fixed so I can actually enjoy driving this new to me Jeep, which I haven’t been able to do yet.

The mechanic told me that unless it gets worse and it’s some sort of a mechanical issue somewhere else that that is, that would be a problem. He seems to still think it’s the tires..

The tires are not really that old. I’ve had them rebalanced rotated and still have the same issue.

If you need any more information to help me resolve this issue, I will gladly add it to this thread.

I do know that once it stopped raining here in Georgia. I’m gonna jack up the entire Jeep. Get the tires off the ground put the axles on. Jack stands front and back gonna do this safely then put it in gear. Let it idle and drive which is 2 Wheel Dr. 1st see if I can fill anything or hear anything then move up to four-wheel-drive high and see if I can fill anything or hear anything. I’ll be damn if I’m gonna let this thing whoop me.
 
I know it was said on another thread but really check the flex plate
 
I know it was said on another thread but really check the flex plate

I did check the flex plate about a month ago ago…I didn’t see any cracks at all. I even started the engine with the inspection cover was off (have a video of that) and it was rotating true, no noises and no wobble at that time.

Maybe I need to check it again

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Me too!!
Wonder if that’s causing all my issues ….

It won’t do you any good and you certainly don’t want it to get worse-

Every noisy is always telling you something

They squawk like women
 
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I was looking at that photo agin closely …looks like either the ring gear was spliced together…I see a piece of metal..that’s 180°
Right above that tooth and an locking ledge above that…
 
You were correct! I don’t know how you figured that out but my master mechanic…check it out today..and said it was a “ Whipe” and wiped it off…he also check the other sections of the flex plate and it all looked good.

I am glad I was correct , that is much better for you ! Ive been around the block a time or two . Thanks for letting us know what was found !
 
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My mechanic ( fantastic gentleman he is) also today put (1) new spicer u joint on the rear driveshaft..it had some roughness to the needle bearings and one side and had a bit of pitting and signs of grinding on the actual u joint.

Now my jeep is a lot more quiet in the cab while driving it…I’m happy that we’re ( he and I) are getting close to hopefully locating the bit of roughness that I feel coming from the front when slowing down and the feeling of something loose.

We’re gonna keep moving forward…I’ll do my part checking things out also..

Still can’t explain the noise I hear on the videos on start up…I’m wondering it that could be a sign of a failing torque converter or rear tail shaft bearing ( does it spin when the automatic transmission is rotating?)
 
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My mechanic ( fantastic gentleman he is) also today put (1) new spicer u joint on the rear driveshaft..it had some roughness to the needle bearings and one side and had a bit of pitting and signs of grinding on the actual u joint.

Now my jeep is a lot more quiet in the cab while driving it…I’m happy that we’re ( he and I) are getting close to hopefully locating the bit of roughness that I feel coming from the front when slowing down and the feeling of something loose.

We’re gonna keep moving forward…I’ll do my part checking things out also..

Still can’t explain the noise I hear on the videos on start up…I’m wondering it that could be a sign of a failing torque converter or rear tail shaft bearing ( does it spin when the automatic transmission is rotating?)

I hope you guy's find the vibe's / noise quickly ! The rear tail shaft bearing turns when the Jeep is moving/driving. Also just my .02 cents worth , both rear u-joints should be replaced at the same time. However , this is not to criticize your mechanic !!! I have done partial repairs trying to narrow something down , He is likely a great guy trying not to spend every dime you have troubleshoot the issue. May the wind be at your back fellers!
 
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I hope you guy's find the vibe's / noise quickly ! The rear tail shaft bearing turns when the Jeep is moving/driving. Also just my .02 cents worth , both rear u-joints should be replaced at the same time. However , this is not to criticize your mechanic !!! I have done partial repairs trying to narrow something down , He is likely a great guy trying not to spend every dime you have troubleshoot the issue. May the wind be at your back fellers!

Colojeep
I just wandered to update you on our most recent findings.

I went back to my mechanic shop yesterday.
We ( the mechanic) and I..discovered yesterday…after putting the jeep on the drive on ramp..lifted up the jeep with all (4) tires off the ramp..I put Jeep in D..rear passenger side free spinning at idle…we heard a noise..we put our hand on the non rotating rear driver side wheel ( that wheel bearing not rotating either) and could feel a bit of catching metal against metal and some noise while holding that wheel…we then went to passenger side rest tire…slowly stopped the wheel from rotating and felt the same exact same noise, catching metal against metal ( wheel bearing not rotating)…we discussed what we discovered and scratched our heads..we believe I have a bad spider gear or gears.
I noticed on past Friday ..when backing up a fairly steep concrete driveway..the rear end was hopping up the drive ( not smooth rolling at all) ..also if I drive down a fairly steep street and make a turn left or right turn and the jeep rear goes steep into the turn either direction..I get some tire hopping…
So, I ordered new spider gear kit and my mechanic said I can use his lift so, I can have clearance to get the rear differential to drop, pull the pan, remove current spider gears and install the new set..what a great gentleman he is..I appreciate him and his knowledge and alway willing to chat with me when I just show up out if the blue with an issue.

I will report back once I get new spider gears installed and have a smooth rolling rear end
 
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Novak Conversions Jeep Wrangler TJ engine mounts