NSG370 Transmission Question About Reverse Gear

I will admit to liking the ratios on the 6 speed. My LJ was great, still performed well enough with 33s on 3.73 gears, and didn't give me any of the durability issues I've heard of on the forums.

The Ax15 just gives me more peace of mind knowing repair and replacement is easy to find.

My next one will probably be a 42rle, because it's going to be an LJ and I want to keep it long term without worrying about what I'll do if the transmission craps the bed, or if crown is gonna discontinue their upgraded OPDA or the fixed PCMs stop being available, which means it'll be an 04 and as far as I know they only came that year with the auto.
 
The NSG370 is also used in the JKs. I'm sure a lot of the parts are swappable, though the bellhousing and input/output shafts are different.

There are even other ratios that exist for the NSG370. A 0.79 6th gear is used in place of an 0.84 6th gear in the later JKs, and certain European applications have a 5.01/2.83 1st/2nd gear ratio instead of the 4.46/2.61 used in the Jeep applications.
 
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I also love my 6 speed. It is smoother then my Honda. A lot of people don't understand how syncro's operate. Some gear boxes are more forgiving then others. Some have weaker syncro's that don't like being abused and then get the label as "unreliable".

For example the transmission in my Honda does not like being skip shifted, either up or down the gear pattern. The syncro's will develop burrs that can make the transmission unusable. I do a monthly session of running the shifter through the gear pattern with the clutch pushed in 1-2-3-4-5-6-R-6-5-4-3-2-1 two or 3 times on both my vehicles. This plus not skip shifting and running the shifter through the gears on deceleration (as in 4th gear slowing down to stop push clutch in move shifter to 3rd then down to 2nd then neutral because the next gear will be 1st) instead of 4th gear push clutch in go to neutral then 1st to start. Hope this makes sense.

This is my routine for reverse.
1) Push the clutch in and start it up.
2) Release the clutch in neutral. Count to 30.
3) Push clutch in and hold it down in neutral and count to 5.
4) Move the shifter to reverse. Once in a while you will get locked out which you can feel by the shifter not going all the way into reverse. If that happens keep the clutch pressed in and go to 4th then back to neutral and then release the clutch. Go back to number 3 and try again.
 
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Another factoid: It is my opinion that double clutching will help ANY transmission shift smoother. Necessary? Not always, but it *can* help.
 
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There’s a company in Tennessee that rebuilds them. There are videos floating about what fails and how they rebuiled them. I called and they quoted me $1600 (don’t quote me).
 
When I bought my '05, reverse was soon unusable and second was going fast. There are flaws in the early days of the NSG370 with the syncros and shift forks (Trans shop info, not verified through research). The NSG370 mercedes already had in their e-series and Chrysler crossfire and was adapted for the wrangler. There was a TSB over said issues. It ended up being cheaper to buy a remanufactured than to have it rebuilt because of the labor involved in the rebuild. from what I gathered, the main differences was in the bellhousing and shift tower, but other than that its a car transmission, that's why its great on the highway but IMO sucks in any type of torque situation. Maybe because my clutch is crap again and I had to drop the coin on a tranny so soon after just buying her. The trans shop guy told me the fluid was mostly bars trans fix that the car lot used just to get it off the lot.
 
When I bought my '05, reverse was soon unusable and second was going fast. There are flaws in the early days of the NSG370 with the syncros and shift forks (Trans shop info, not verified through research). The NSG370 mercedes already had in their e-series and Chrysler crossfire and was adapted for the wrangler. There was a TSB over said issues. It ended up being cheaper to buy a remanufactured than to have it rebuilt because of the labor involved in the rebuild. from what I gathered, the main differences was in the bellhousing and shift tower, but other than that its a car transmission, that's why its great on the highway but IMO sucks in any type of torque situation. Maybe because my clutch is crap again and I had to drop the coin on a tranny so soon after just buying her. The trans shop guy told me the fluid was mostly bars trans fix that the car lot used just to get it off the lot.

yeah, 2nd occasionally grinds as well, not very often though. We’ll see how she runs with all the new information.
 
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
It's a fix for a worn gear selector, which causes poor shifting between 1st, 2nd, and 3rd. Shifting into reverse is very positive with the B&M, but grinding into reverse gear is the transmission.
 
The NSG370 is also used in the JKs. I'm sure a lot of the parts are swappable, though the bellhousing and input/output shafts are different.

In your opinion, are the durability and service concerns commonly expressed, overblown? It seems to have a reputation of being a throwaway box where the parts are so expensive and hard to find that total replacement is often the least horrible solution.

My NSG370 was low mileage and well maintained when I had it, so as I said before, I had no problems with it. But I HAVE been burned by poor maintenance by previous owners before so the transmissions reputation makes me skiddish about getting a higher mileage one, which is just going to be a fact of life buying an LJ 10+ years older than mine was when I got it.
 
In your opinion, are the durability and service concerns commonly expressed, overblown? It seems to have a reputation of being a throwaway box where the parts are so expensive and hard to find that total replacement is often the least horrible solution.

My NSG370 was low mileage and well maintained when I had it, so as I said before, I had no problems with it. But I HAVE been burned by poor maintenance by previous owners before so the transmissions reputation makes me skiddish about getting a higher mileage one, which is just going to be a fact of life buying an LJ 10+ years older than mine was when I got it.
Here is my opinion on it.

Is it the most reliable transmission available for a TJ? Probably not. The AX-15 would probably outlast a 6 speed.

Is it reliable enough? I think so. I have never seen a thread where it fails catastrophically and without warning. It always shows symptoms. So chances are, you will know if it's on its last legs.

Would I buy another NSG370? Absolutely. The ratios more than make up for its drawbacks, in my opinion. While the parts aren't widely available to the public, many companies still offer remanufactured NSG370s for the TJs. And the remanufactured JK NSG370s will probably stay around for quite a bit longer.

The NSG370 is also rated to about 270 ft-lbs of torque for factory applications. A Golen Stroker would be right at that limit. A moderate supercharged 4.0 would only exceed that by maybe 15%, which isn't likely to cause failure. So it's not going to blow up like an AX-5 if you throw a bunch of torque at it.

Plus, I really don't know of any other TJ transmission that gives three very useful gears on the freeway when the axles are properly geared. Want to climb steep hills at 75 mph? 4th gear is perfect for that. Meanwhile, the automatics and the 5 speeds don't really get you as close to the power band at freeway speeds as the NSG370 can.