NSG370 sounds like a diesel

robbierobot

robbierobot

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I have an 06 LJ 4.0L with the NSG370. Over the past year or two it has been sounding like a powerstroke at idle or less than 1500rpm after load is applied seems to go away. Most loud around the underside of the jeep between motor and trans. Rather than push my luck anymore its time to deal with it. I have read through many 4.0L threads piston slap, cracked manifold, valves, timing chain etc.. it has roughly 125k miles. Poking around with the stethoscope it seems to be coming from the bell housing. Why didn't they put an inspection plate on these things? Is it worth borescoping into the started hole or just start yanking it out and see what the issue is.... I'd rather keep the 6spd as it get highway miles to the trails. I have also read up on the nsg370 and their issues, I do not believe this is "just a loud transmission" issue as you can hear it from across the parking lot.
-Thanks
 
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Both the ax15 and nv3550 have higher(numerically lower) over drives. Meaning they would both get you better highway miles to the trail. The nsg has a lower first gear which makes it better on the trails.
 
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Thanks for pointing that out, definitely something to consider.
NV3550 1st = 4.01 2nd = 2.33 3rd = 1.39 4th = 1.00 5th = 0.78 R = 3.57
NSG370 1st = 4.46 2nd = 2.61 3rd = 1.72 4th = 1.25 5th = 1.00 6th = 0.84 R =4.06
 
The nv3550 is no longer in production and quality replacement parts are a thing of the past. My nv3550 is on its last leg. I will most likely end up buying a brand new AX15 from Advanced Adapters or Novak. the ax15 has the worst gear ratios of the 3, but its arguably the most reliable.
 
Mine sounded pretty bad...pull the transmission and check the tob.
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Thanks, I think I'll still pull it and check on that. The clattering I hear doesn't have any whine or sqeal to it and the noise remains the same clutch in or out
 
Mine was clacking and rattling, kept driving it, got wet in a water crossing, began intermittent squealing, kept driving it, started squealing alot when pedal was pressed, barely made it to my buddies shop to change the clutch pedal was getting stiff.
 
My whined a good bit then it was an all out scream:eek:. When we pulled it apart there were ball bearings laying in the bottom of the bell housing from the TOB...... the clutch looked fine, even with 120,000 miles on it, we replaced it anyway since we had it all apart.
 
The 2.4/NSG combo's use a dual mass flywheel to dampen engine to drive-line vibration instead of the springs in the friction plate. I'm not sure if the 4.0/NSG combo's use this as well. I guess when the springs collapse in the flywheel they will chatter under load. Its a fairly over complicated clutch set up compared to past jeeps and the flywheel is insane expensive (~400$ for a LUK). Like I said, not sure if the 4.0's are the same, but its something to look at.
 
Wanted to update for anyone in the future. Turns out that the Redline MTL did wonders as far as reducing the sound. Never had any shifting issues what so ever but it shifted smooth with the MTL as well
 
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