NSG370 Transmission Question About Reverse Gear

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retlawblackhawk

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New TJ owner in the last few weeks, 05 with manual 6 speed and had a question on the nsg370. I’m having the grinding into reverse issue. I’ve taken all the advice and can avoid it using various techniques.

However I am a bit confused with all the reading I’ve done here and online, reading thru the nsg manual, etc.

The clarification I’m looking for is this: the manual clearly indicates there is a reverse sync ring but the advice that “works” is based on techniques as if there were no synchro on reverse. Is it just simply that even though the trans has a sync ring it still needs to be treated like it doesn’t?

thanks in advance!
 
On my 6 speed I go fifth then down to reverse and it works fine. You're basically forcing the synchros to line up by doing that, but I'm also curious what the proper fix i
 
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I've had two 6 speeds and they shifted fine into reverse. They would grind once in a while when I didn't hit reverse just right. Nothing compared to the AX-15 with no synchro. My NV3550 has zero issues.
 
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A synchro doesn't always help the gears line up. It gives it a bigger chance though.

Through time, I have learned when it will and won't grind. If you pay attention to the shifter while going into reverse, you will see or feel that it doesn't quite come back all the way when the gear teeth stack up on each other. If you let the clutch out then, you know it will grind. Instead of letting the clutch out, put it in another forward gear and try again. Alternatively, let the vehicle roll a bit and try again.

The feeling you get in the shifter is the same feeling you get when shifting from neutral to 4Low at a stop, and the teeth just won't line up. It's more subtle in the transmission, though.
 
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retlawblackhawk said:
This helps explains things and make sense.
Click to expand...
You can even get the same issue going into first or second gear at a standstill on just about any transmission. Ever been stopped at a traffic light, and then realized it just wouldn't go into one particular gear? That's because the teeth on the synchro lined up perfectly. The solution is to try a different gear, or if the original gear is necessary, shift to another gear and back to realign the teeth.
 
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Steel City 06 said:
A synchro doesn't always help the gears line up. It gives it a bigger chance though.

Through time, I have learned when it will and won't grind. If you pay attention to the shifter while going into reverse, you will see or feel that it doesn't quite come back all the way when the gear teeth stack up on each other. If you let the clutch out then, you know it will grind. Instead of letting the clutch out, put it in another forward gear and try again. Alternatively, let the vehicle roll a bit and try again.

The feeling you get in the shifter is the same feeling you get when shifting from neutral to 4Low at a stop, and the teeth just won't line up. It's more subtle in the transmission, though.
Click to expand...
^^THIS^^
I'm slightly surprised that reverse has synchros - I thought they didn't!
 
Zorba said:
^^THIS^^
I'm slightly surprised that reverse has synchros - I thought they didn't!
Click to expand...
They don't until a certain point in the 05-06 cycle. I'm not quite sure when they were added, but at some point Jeep issued a TSB recommending that they be installed in 05 models that didn't have them. So some do, some don't. I believe all JK models have reverse synchros
 
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Steel City 06 said:
They don't until a certain point in the 05-06 cycle. I'm not quite sure when they were added, but at some point Jeep issued a TSB recommending that they be installed in 05 models that didn't have them. So some do, some don't. I believe all JK models have reverse synchros
Click to expand...
That makes sense now, mine is dated 10-11-2004 so it’s very likely it was an earlier one without, and from the carfax I see no indication it was ever updated, so that explains why it behaves like one without, probably doesn’t have it.
 
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Steel City 06 said:
A synchro doesn't always help the gears line up. It gives it a bigger chance though.
Click to expand...

right. It gets them going the same speed, but sometimes they end up going the same speed with the teeth lined up with each other instead of between each other.

I have an AX15 so I get to experience this about 1 out of every 4 times I go into reverse even after I go into a forward gear first to get them spinning together.
 
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Have any of you installed the B&M shorty throw shifter?

heard that helped fix many of the short comings of the NSG370. But at $550. It isn’t exactly cheap
 
freedom_in_4low said:
right. It gets them going the same speed, but sometimes they end up going the same speed with the teeth lined up with each other instead of between each other.

I have an AX15 so I get to experience this about 1 out of every 4 times I go into reverse even after I go into a forward gear first to get them spinning together.
Click to expand...
If you've held the clutch in long enough and the vehicle isn't moving, neither side of the gearset is spinning. Putting it into another gear simply forces the shafts to rotate slightly as those synchros rotate it to line it up.

Rolling the vehicle also forces the other shaft to rotate as well.
 
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Steel City 06 said:
Through time, I have learned when it will and won't grind. If you pay attention to the shifter while going into reverse, you will see or feel that it doesn't quite come back all the way when the gear teeth stack up on each other. If you let the clutch out then, you know it will grind. Instead of letting the clutch out, put it in another forward gear and try again. Alternatively, let the vehicle roll a bit and try again.
Click to expand...


X2 to this. I've only owned my NSG370 equipped TJ for several months now, but in that time I've very quickly learned when it will grind and when it won't. You can literally feel it when going into reverse, and sometimes all it takes is putting it in neutral and rolling backwards just a few inches to line things up perfectly to where it won't grind.

I will say this is the best transmission I've ever owned in a TJ. It feels absolutely perfect paired to the 4.0 and the TJ.
 
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If it won't go into reverse, I put it back in neutral and cycle the clutch, pause, and try again. That's just automatic with me after a lifetime of driving manuals. *shrug*
 
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TurboTJ said:
Oh boy..... I hope you have your flame suit on.
Click to expand...

Don't get me wrong, I'd still prefer the automatic in very tight, difficult wheeling situations off-road, but for daily driving and such, I love this NSG370 so much more than the two 42RLEs I've owned.
 
Chris said:
Don't get me wrong, I'd still prefer the automatic in very tight, difficult wheeling situations off-road, but for daily driving and such, I love this NSG370 so much more than the two 42RLEs I've owned.
Click to expand...

Do you use all the gears? I have a tendency to skip 1st and sometimes 5th.
 
Cedar128 said:
Do you use all the gears? I have a tendency to skip 1st and sometimes 5th.
Click to expand...

Starting off I will sometimes skip first and start in second. I always use 5th and 6th though, but that’s because the speeds on the highways here are 85 MPH and sometimes 90.
 
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The best thing about the NSG370 is that you have three very useful gears on the freeway, assuming the car is properly geared. Most other transmissions really have only two.

At 75 mph with 35s and 4.88s:

6th gear - cruising at ~3000 RPM. Good for most conditions.
5th gear - torque at ~3500 RPM for moderate hills.
4th gear - Maximum power at ~4500 RPM for merging, passing, steep hills.
 
I too like this transmission - oh, its not my beloved SM-420, but it also has more gears than that one does. Nice, smooth shifting gearbox.
 
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