It has begun: My attempt at rebuilding my 6-speed NSG370


I'll share this as well, from High Gear, but since this is one of the better NSG370 threads I've found. He talks about shifting forks, shows some that have no plastic, but he points out that the ends of them are rubbed down (metal rubbed away) where our plastic forms are, and it's from resting your hand on the shifter and basically pushing it against the edge of the slider in the transmission. It will also bend the end of the fork as well over time. Either way, creates slop etc. So, if you keep your hand on and push against it "while cruising for chicks" ha, the plastic forms will have a longer life.

I love his point on the clutch....it's the LAST thing he talks about. My brother is a 30 year mechanic that now drives big rigs for oil companies out of Houston. "Float the Gears" I hear all the time, starting with my own brother. This guy, who makes money rebuilding Transmissions, says what I think it 100% truth, Big Rigs are built differently, floating is necessary. Our Jeep transmissions are not built for that, over time it rubs the synchros.
 
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Man that looks simple! Couple questions.

1. It looks like the inserts are held on by nubs or molded pins, as well as being bonded. Would have to be bonded otherwise one crack would cause them to fall off I would think

2. Can you see any reason why you couldn't use a stronger material in these spots? Would it create additional wear on the ring? Just trying to get an understanding as to why they would choose to use a synthetic here as opposed to other tried and true materials that last longer.

3. Looking at the synthetic guide where the rods go through, can you tell if this is bonded as well or simply snapped into place?

Thanks much for the pics!

PS. My tranny shifted flawlessly right up until I tried to find 8th gear one day. I imagine I might have either bent the fork a little bit or at least chipped off some of the guide. The catch-22 I have at the moment is that it only ever gives me reverse gear grief if I am in 4LO and pointing downhill when wheeling...takes a couple of clutch presses to lock it in. Facing uphill, no problem, so I am probably just out of whack by the thickness of the guide. Not sure if it is worth pulling apart at this time, however snow plowing season for my driveway is coming up where I do lots of 4LO reverse (but on flat-ish ground), so will see.
 
Man that looks simple! Couple questions.

1. It looks like the inserts are held on by nubs or molded pins, as well as being bonded. Would have to be bonded otherwise one crack would cause them to fall off I would think

2. Can you see any reason why you couldn't use a stronger material in these spots? Would it create additional wear on the ring? Just trying to get an understanding as to why they would choose to use a synthetic here as opposed to other tried and true materials that last longer.

3. Looking at the synthetic guide where the rods go through, can you tell if this is bonded as well or simply snapped into place?

Thanks much for the pics!

PS. My tranny shifted flawlessly right up until I tried to find 8th gear one day. I imagine I might have either bent the fork a little bit or at least chipped off some of the guide. The catch-22 I have at the moment is that it only ever gives me reverse gear grief if I am in 4LO and pointing downhill when wheeling...takes a couple of clutch presses to lock it in. Facing uphill, no problem, so I am probably just out of whack by the thickness of the guide. Not sure if it is worth pulling apart at this time, however snow plowing season for my driveway is coming up where I do lots of 4LO reverse (but on flat-ish ground), so will see.
image.jpgimage.jpgimage.jpgimage.jpg

That guide is very tight. There are forms on both sides that looks like tabs, I can't account for how that goes in and is held. Again, I can look at the one that I get back.
 
Man that looks simple! Couple questions.


PS. My tranny shifted flawlessly right up until I tried to find 8th gear one day. I imagine I might have either bent the fork a little bit or at least chipped off some of the guide. The catch-22 I have at the moment is that it only ever gives me reverse gear grief if I am in 4LO and pointing downhill when wheeling...takes a couple of clutch presses to lock it in. Facing uphill, no problem, so I am probably just out of whack by the thickness of the guide. Not sure if it is worth pulling apart at this time, however snow plowing season for my driveway is coming up where I do lots of 4LO reverse (but on flat-ish ground), so will see.
Well, that would stand to make sense. If I have my mind right, you would have been in the farthest passenger side rail of the fork, pushing over to reverse and back? I would think you could bend, or your reverse was close to toast, and that finished the job. All manuals in the config, you hit reverse at massive RPM, ouch, doesn't take much.
 
Mine pops out of reverse every now and again. Kinda wonder if new forks and this guide plate would be the fix. I feel like that would be something I'm much more prepared for than a full rebuild.
 
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Mine pops out of reverse every now and again. Kinda wonder if new forks and this guide plate would be the fix. I feel like that would be something I'm much more prepared for than a full rebuild.
I have sent a message to this person asking how the brass plate is working but have not heard a rep.y back..I guess I need to call him and talk to him.mine wor,s fine except pops out of second gear I'm sure it's a synchro.at least I hope that's all just bought a shop press and the tool to pull the cases .
 
I haven't, but I wish I had seen this when I had mine rebuilt. I only had my silver 05 TJ for a little while, but that one had the reverse, and I got to where I could let up slowly on the clutch and it would engage with no grind etc. I could do it every time, don't know why it like that, but it would notch in. My rebuilt black TJ hasn't had reverse ever, just the 2nd grinding, but I thought this part looked like junk when I bought it, this looks much beefier.
 
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Mine is getting to be a pain shifting into reverse. Everything else is smooth as butter. Anyone try or have success with replacing the shift rail guide plate with the bronze one?

https://whitbreadperformance.com/products/nsg370-shift-rail-guide-plate

There was a known defect with reverse in the NSG370 that was addressed by redesigning some parts but not the shift rail. The updated parts were used throughout the JK era NSG370s and are included in all the rebuild kits.

You may need a new shift rail but that is unlikely to resolve your reverse issue by itself. I waited until I could no longer reliably get it into reverse before biting that expensive bullet but it was worth it. I bought a rebuilt NSG370 from High Impact that I've been completely happy with.

https://high-impact.net/nsg-370-rebuilt
 
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There was a known defect with reverse in the NSG370 that was addressed by redesigning some parts but not the shift rail. The updated parts were used throughout the JK era NSG370s and are included in all the rebuild kits.

You may need a new shift rail but that is unlikely to resolve your reverse issue by itself. I waited until I could no longer reliably get it into reverse before biting that expensive bullet but it was worth it. I bought a rebuilt NSG370 from High Impact that I've been completely happy with.

https://high-impact.net/nsg-370-rebuilt

Ok, cool. I have read most, if not all the threads on this topic on the forum, and looked at High Impact, but getting your review on their rebuild is nice. This is a complicated transmission that needs special tools to rebuild. I just hoped I could resolve it myself with the rail. At least there is a good rebuild available, as well as the 5-speed option (with more work). Of course, I’d probably prefer an auto, but that’s a lot more work!
 
I have an 06 with the 6 speed. I plan on changing the transmission fluid this summer, so I have been watching NSG370 threads. When I went to the HIgh Impact link and then to their oil chart, I noticed they recommend either Valvoline or Amsoil manual transmission fluid.
 
just food for thought, mine was a mid-late 06 which should have had the updated reverse parts but still had reverse problems. I had a trick for getting in but if I was reversing against any resistance it would pop out; the more resistance, the more violently. It's possible that my LJ's transmission was particularly abused over it's life before my ownership, more than any of the other dozens of manual trans vehicles I've owned, or that even with the revised parts that reverse is still a weak point of the NSG370.
 
just food for thought, mine was a mid-late 06 which should have had the updated reverse parts but still had reverse problems. I had a trick for getting in but if I was reversing against any resistance it would pop out; the more resistance, the more violently. It's possible that my LJ's transmission was particularly abused over it's life before my ownership, more than any of the other dozens of manual trans vehicles I've owned, or that even with the revised parts that reverse is still a weak point of the NSG370.

I had an 05 TJ that popped out of head in 1st and sometimes reverse. And driving these trannys for 15 years, some new and some as much as 150k miles in both TJ/LJ and JK. I gotta good feeling for them.

The 05 I had you can feel that when the gear engages in first (for example) the engagement point was just a wee bit off, worn guides? Bent fork? Who knows.

But what did work was adding the stupid expensive B&M shifter, I felt that gear go in solid THEN I dent the detent. So I know that shifter was solidly engaging that fork/gear assembly. NEVER had a pop out on that transmission after.

Typically the shift forks have a detent on the shift rail that accurately places the rail and ensures proper engagement. It’s solid. What the NSG gas is the detent in the SHIFTER the furthest point from the action, so alllll of the slop downstream stacks to the point where the shifter cannot locate the fork properly and allows the gear to pop out and/or not completely engage.

BTW: there are multiple design weaknesses that allow slop in the transmission design.

These are great transmissions, and awesome 5 forward gear 1 OD arrangement, and shift great … until you reveal their weaknesses.

New B&M shifter, shift guide plate from HERE, and new shift fork assembly should have you a robust transmission for a very long time …
 
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But what did work was adding the stupid expensive B&M shifter, I felt that gear go in solid THEN I dent the detent. So I know that shifter was solidly engaging that fork/gear assembly. NEVER had a pop out on that transmission after.

.

Indeed!
 
I had an 05 TJ that popped out of head in 1st and sometimes reverse. And driving these trannys for 15 years, some new and some as much as 150k miles in both TJ/LJ and JK. I gotta good feeling for them.

The 05 I had you can feel that when the gear engages in first (for example) the engagement point was just a wee bit off, worn guides? Bent fork? Who knows.

But what did work was adding the stupid expensive B&M shifter, I felt that gear go in solid THEN I dent the detent. So I know that shifter was solidly engaging that fork/gear assembly. NEVER had a pop out on that transmission after.

Typically the shift forks have a detent on the shift rail that accurately places the rail and ensures proper engagement. It’s solid. What the NSG gas is the detent in the SHIFTER the furthest point from the action, so alllll of the slop downstream stacks to the point where the shifter cannot locate the fork properly and allows the gear to pop out and/or not completely engage.

BTW: there are multiple design weaknesses that allow slop in the transmission design.

These are great transmissions, and awesome 5 forward gear 1 OD arrangement, and shift great … until you reveal their weaknesses.

New B&M shifter, shift guide plate from HERE, and new shift fork assembly should have you a robust transmission for a very long time …

That shift guide plate is trick. Wish I saw that three years ago.

I bought the stupid expensive shifter too. I’m hoping to helps my 1-2 shift engagement.