NSG370 Transmission Noise

Leroy_TJ

2006 Jeep TJ Wrangler X
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327
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Leroy,Alabama
Need some help. I have a 2006 TJ X (147k miles) with a 6 speed transmission NSG370. The jeep was geared to 4:56 a couple months ago. After a couple weeks after the gears I started hearing a grinding noise ,my first thought was the gears since that was the only thing I have changed so I took it back to the mechanic who done the gears he checked over everything and was very diligent. He listened for the noise with the wheels off the ground at the diffs and could not hear anything.
So we took the Jeep for test ride and the noise could be heard in the trans area, it wasn’t very loud at the time and was hard to pin point it from in the Jeep (soft top). We drained the fluid in the trans and transfer case and put mopar trans fluid and atf fluid in the transfer case. The noise was still there but not as loud. That was a month ago. Today I made a 20 mile trip to watch my daughters softball game and the noise was very loud especially in 5th and 6th gear. Again hard to pin point it inside the Jeep. While at the game I read in another forum that I could I put my transfer case in neutral and shift through the gears to see what gears were making the noise.
The grinding noise starts in 3rd gear and gets louder in 4th ,5th and 6th. It does not do it in 1st ,2nd or reverse. I am attaching a video with transfer case in neutral shifting through all the gears.
Can anyone help me with what to do ? I don’t have a transmission shop within 100 miles of me. Any help is greatly appreciated.
I am trying to be as descriptive as I can. Sorry for the long post.
 
I couldn’t get the video to attach. I also forgot to add the clutch and throw out bearing was replaced after the fluid change.
 
some searching at this forum should turn up several threads where we say the nsg370 sounds like there is loose gravel in there, and that's just how it is. so i lived with mine for seven years. mine was especially bad with the trans input shaft rattle, ie noise in neutral with the clutch not pushed in. push in the clutch. the input shaft stops spinning, and the noise goes away.

anyway, due to other vehicle breakdowns, last summer i pulled my boat to the lake with the lj. in all the years i have owned it, it has spent maybe 8 minutes in 5th gear; i always shift from 4 to 6. but pulling the boat i used 5th, and yikes, it was so quiet compared to 4th and 6th. this is when i realized the noise had been getting worse all these years. finally now i had to start holding the clutch in at the drive-tru speaker to hear.

so this winter, i broke down and got a rebuilt unit from www.high-impact.net. they are in ca, but are just a reseller for the outfit in memphis. first test drive about a week ago, and holy cow, it sounds like an electric car compared to before :)

i love my nsg370, and it is not noisy at all.
 
From what I am reading it sounds like the input shaft is what’s causing the noise on mine. Thanks for the link , I am going to give them a call tomorrow. What outfit in Memphis ? I am just now diggin into this about the nsg370.
 
I couldn’t get the video to attach. I also forgot to add the clutch and throw out bearing was replaced after the fluid change.
Post it on youtube and then post the youtube link here, thats what I did with my OPDA noise.
They are a strange gearbox thats for sure one drive perfect the next not, I will say that my box got considerably worse with the Redline swap, could just be coincidence though? I have only just re mastered my 1st to 2nd shift after the Redline swap without grinding, I have to pull the gear stick (push it for LHD) slightly to the right as if to go in neutral but not as far and it slips in second without grinding.
 
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If it makes you feel any better my nsg370 started to be a lot noisier about 40,000 miles ago at highway speeds, especially after driving a while. I was very disturbed and believed the transmission was going to blow up any second. Fast forward a few years and I don't even worry about it. Yes it is annoying but from all I've read this issue seems to be very common with this transmission. One of these days I might purchase a rebuilt one or do the ax-15 conversion but I'm not worried about my nsg370 failing any time soon and its pushing 200k.
 
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If the Transfer case is in Neutral the output shaft is still spinning. While the noise progressively gets louder at higher gears, it's indicative of the output shaft bearing. It's spinning at a higher rpm.

It could also be something in the Transfer case. I'd suggest dropping the transfer case and run the Transmission through the gears. If the noise is still there, it has eliminated the possibility of the transfer case.
 
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some searching at this forum should turn up several threads where we say the nsg370 sounds like there is loose gravel in there, and that's just how it is. so i lived with mine for seven years. mine was especially bad with the trans input shaft rattle, ie noise in neutral with the clutch not pushed in. push in the clutch. the input shaft stops spinning, and the noise goes away.

anyway, due to other vehicle breakdowns, last summer i pulled my boat to the lake with the lj. in all the years i have owned it, it has spent maybe 8 minutes in 5th gear; i always shift from 4 to 6. but pulling the boat i used 5th, and yikes, it was so quiet compared to 4th and 6th. this is when i realized the noise had been getting worse all these years. finally now i had to start holding the clutch in at the drive-tru speaker to hear.

so this winter, i broke down and got a rebuilt unit from www.high-impact.net. they are in ca, but are just a reseller for the outfit in memphis. first test drive about a week ago, and holy cow, it sounds like an electric car compared to before :)

i love my nsg370, and it is not noisy at all.
My NSG370 recently starting making the noise in neutral. I switched to Red Line MTL about 10 months ago, but I doubt that has anything to do with it. It still shifts fine. Not my video, but it sounds like this

Centerforce explaining it here

I've been slowly getting comfortable doing various things on vehicles on my own, but for transmission work, I might leave it to the professionals.
 
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I called High Gear Transmission this morning waiting on a tech to call me back.
@Rubicon88 , I will give Sachs a call. It was really loud yesterday 30 miles in 6th gear.
I appreciate the help.
 
I called High Gear Transmission this morning waiting on a tech to call me back.
@Rubicon88 , I will give Sachs a call. It was really loud yesterday 30 miles in 6th gear.
I appreciate the help.
Do you notice any change in volume...louder...

Like when you first start versus after running for 30 Min. ?

Or on a cold morning start versus being warned up
 
It’s quiet in 1st and 2nd as soon as shift to 3rd I can start hearing it. It’s gets louder the longer I go.
It’s been there but not as loud on short trips , I drive just six miles to work everyday and only get into 5th gear for a short distance never get into 6th. It got loud on me on the longer drive Tuesday running 65-70mph in 6th
 
It’s quiet in 1st and 2nd as soon as shift to 3rd I can start hearing it. It’s gets louder the longer I go.
It’s been there but not as loud on short trips , I drive just six miles to work everyday and only get into 5th gear for a short distance never get into 6th. It got loud on me on the longer drive Tuesday running 65-70mph in 6th
Any noise in neutral
 
From what I am reading it sounds like the input shaft is what’s causing the noise on mine. Thanks for the link , I am going to give them a call tomorrow. What outfit in Memphis ? I am just now diggin into this about the nsg370.
high gear is the outfit in memphis. i read you called them. they sound like they know what they are doing, and they have several good videos on youtube.

the crazy thing is high impact (in ca) quoyed me less than high gear, and later i realized high impact simply subs it out to high gear :)
 
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high gear is the outfit in memphis. i read you called them. they sound like they know what they are doing, and they have several good videos on youtube.

the crazy thing is high impact (in ca) quoyed me less than high gear, and later i realized high impact simply subs it out to high gear :)
High Gear Tech didn’t call me back yet. I am going to call High Impact Monday and get a quote.