NSG370 Grinding in Reverse

impish123 · 04-16-2009, 07:48 PM

Ok, so I have been looking around this forum since I bought my 05 Unlimited this past December (I had an 01 TJ before) and have yet to see a straight answer to this...
Right after I bought my LJ I started to notice that going into reverse was somewhat difficult and it would occasionally grind a bit. Recently the grinding has become almost constant while releasing the clutch with the tranny in reverse. I have tried numerous tricks and have yet to find a way to prevent the grinding. The tranny will grind, I will push the clutch again and slowly release again and sometimes it goes fine, other times it grinds again. Is this a common occurrence with the NSG370 (I cannot imagine it is)? If it is not, what could the cause be? Finally, is it easily repairable? Thanks everyone in advance.

RubiconR6 · 04-16-2009, 11:28 PM

i just put one the NSG370 in my 03. my reverse does the same thing. the NV3550 is going back in so i can fix the NSG370. when i get it done i will let you know.

jeep06 · 04-16-2009, 11:35 PM

Silly question.. but have you checked the oil level in it? Many have reported, including me that some if not maybe all of the trannies were shipped low on oil and it may or may not help you in this case. I don't have any problems with mine going into reverse and causing grinding unless I get my timing off on the clutch/shifting and in a hurry. I tried a few different oils in mine.. the best I have found for smooth shifting is Amsoil syncromesh... and no I am not pimping or selling the product! Good luck and keep us posted... welcome to the forum also!!!

RubiconR6 · 04-16-2009, 11:53 PM

done checked the oil level not it. I am thinking its the synchronizer. Where did you find that oil at{Amsoil syncromesh... }

jeep06 · 04-17-2009, 12:22 AM

Quote:

Originally Posted by RubiconR6

done checked the oil level not it. I am thinking its the synchronizer. Where did you find that oil at{Amsoil syncromesh... }

Yep it's probably the syncro then. The easiest way I've found for me to get the oil is on-line at their website.... http://www.amsoil.com/. If you are planning on buying very much of it, it's cheaper to pay the $10 for the preferred customer subscription and save about $2/qt. A lot of people on here complain about their oil.. probably because most of them have never tried it, but I have no complaints about it in anything I've used it in.

dricex · 04-17-2009, 12:46 AM

I switched out the fluid in my transmission with Royal Purple Synchromax. The transmission feels a lot better. I purchsed the fluid at O'Reilly for about $9.00 a quart.

impish123 · 04-17-2009, 07:35 AM

When I get a chance, I plan on replacing the fluid, but have as yet not gone that direction. That was one of my thoughts. I have done the reading regarding both types of oil (the topic has been beaten to death) and plan on changing it when I get a day off. RubiconR6, when you tear yours apart, let me know what you find. Thanks for the information so far guys!

impish123 · 04-20-2009, 03:35 PM

Changed the fluid today and no joy. Also found a good deal of metal on the magnet, probably time to have it rebuilt... Anyone have any other ideas? It slips out pretty much all the time now. The shifts are still very smooth 1-6, just that reverse gear is toast. Anyone got some other options, other than rebuilding it?

Heyduke · 04-20-2009, 03:56 PM

From what I've found there is no synchronizer for reverse. If that's the case then one has to feel it into reverse to avoid gear clash. Mine used to grind until I figured out I needed to wait a tick, and finesse it into gear.

impish123 · 04-20-2009, 04:23 PM

From what I have read the NSG370 has a synchronizer for reverse. I have waited numerous seconds, tried numerous different tricks to get it to stick in reverse and nothing has seemed to work.

TJMunky · 04-20-2009, 04:25 PM

these transmissions have a tendency to not sync right away when put into reverse i have one on my 05 and the best way to make sure you dontgrind is to hold the stick back and let off the clutch slowly. thats about all the advice anyone can give you.

TJMunky · 04-20-2009, 04:30 PM

This fully synchronized, heavy duty, 6 speed transmission is suited for External Clutch Slave Cylinder use only. The First and Second Gears have triple-cone synchronization, Third and Fourth have double-cone synchronization and Fifth and Sixth have single-cone synchronization. Reverse is also synchronized for easy transfer from forward to reverse gear. Hardened gears allow for quiet operation. The two-piece aluminum case with integrated bell housing provide strength and light weight. Comes with Lower Shifter Tower and Reverse Switch already installed, making for an easy replacement. Gear ratios for the NSG-370 are: 4.46, 2.61, 1.72, 1.25, 1.00, 0.84 for first through sixth

dirkg8989 · 09-14-2009, 05:14 PM

I too have the problem of it not going into reverse. I have an 05 Unlimited, and as far as I know everything is stock (I bought it last year), except the tires 31X10.5/15. Almost every time I put it in reverse it pops out again as I start to back up. If I start to back up and keep pressure on the stick, I can sometimes force it into gear so it stays, but other times it is just too hard to hold into gear. Then I have to stop and try again. Very Frustrating, and It sounds like I'm destroying the tranny.

Is this common? As a last resort, I will try changing the oil but I don't think that is it. It feels to me like it just doesn't get far enough in gear. I will try removing the boot and carving up the console first, that sounds more promising.

**Jerry Bransford** · 09-14-2009, 05:20 PM

The following age-old shifting technique should stop the grinding when you don't have a synchronized Reverse gear or if the synchronizer has gone bad.

When you are ready to shift into Reverse and you have the clutch pedal down ready to shift, simply first shift into 1st gear (or any forward gear) for a brief moment and then immediately shift into Reverse. Keep stepping on the clutch while doing the momentary shift into first gear, only let up on the clutch pedal when you're in Reverse and ready to back up. 'Voila, no more grinding.

I was taught that shifting technique in 1963 when I was 15 and learning how to shift a buddy's '57 VW bug that didn't have a synchronized Reverse gear and that technique is still useful to this day.

Kip03TJ · 09-14-2009, 05:34 PM

Quote:

Originally Posted by Jerry Bransford

The following age-old shifting technique should stop the grinding when you don't have a synchronized Reverse gear or if the synchronizer has gone bad.

When you are ready to shift into Reverse and you have the clutch pedal down ready to shift, simply first shift into 1st gear (or any forward gear) for a brief moment and then immediately shift into Reverse. Keep stepping on the clutch while doing the momentary shift into first gear, only let up on the clutch pedal when you're in Reverse and ready to back up. 'Voila, no more grinding.

I was taught that shifting technique in 1963 when I was 15 and learning how to shift a buddy's '57 VW bug that didn't have a synchronized Reverse gear and that technique is still useful to this day.

I've done that with all my cars, either 1st or 5th then straight back. Some cars, like my acura, have the 5th gear lockout so then it's 1st to reverse.