NSG370 Rebuild

[rlinares40]

@rlinares40 I'm thrilled you're tackling this. I'm just down the road from you if you want help or a 2nd set of eyes. I'm fascinated with transmissions, but I've only messed with automatics. Would love to tear into a manual.

Yeah I've usually only rebuilt automatics as well (700r4/4L60e). The thing slowing me down right now is the cost of parts, could probably rebuild a AX15 or NV3550 for around $500. Got a deal on the NSG370 stand and case puller for around $350, if I successfully rebuild this one i'll probably keep all the tools and start to rebuild em for people in the area since most shops wont touch these anymore.

 

[Ericshere03]

I believe the bolt pattern may be different between the TJ and JK's. On TDI Conversions (I'm doing a diesel swap) they list different adapters for the 4.0L and the 3.6L.

Yes, the bolt patterns are different. That’s why I would swap the front transmission case/bellhousing.

 

[rlinares40]

Started pulling some synchros and gears last week.

5-6 Synchro Assembly: Will replace 5-6 Brass Synchros and the Slider.

• The blocker ring looks good on both 5th and 6th,
• The synchro looks a little chewed up on the outside but the inside isn't worn on the 5th
• The synchro for 6th looks good both outside and inside
• The slider teeth look chewed on the 6th side.

5th Blocker Ring and Brass Synchro

5-6 Slider

6th Blocker Ring and Brass Synchro

Reverse Synchro Assembly: Will Replace the Reverse Brass Synchro and Reverse Gear.

• The teeth on the reverse brass synchro look chewed, the inside of the ring isn't worn.
• Forgot to take a picture of the Reverse slider but I think it was in good condition if I skipped taking a picture of it.
• Reverse Gear teeth look chewed.

Reverse Brass Synchro

Reverse Gear

1-2 Synchro Assembly: Will update when I press out 2nd Gear


Shift Fork Assembly:

• As stated before the plastic for the shift rails is broken and will be replaced with Whitbread Performance Brass Plate.
• The plastic that holds the sliders seem to be in very good condition other than the middle plastic pieces on both. Currently trying to figure out a way to avoid having to spend $500-$800 for a new shift fork assembly.

Slider plastic in good condition

Slider Plastic in not so good condition

 

[rlinares40]

Yes, the bolt patterns are different. That’s why I would swap the front transmission case/bellhousing.

would be interesting if the bellhousings were able to be swapped over! Less mileage on the transmission and would come with updated parts like 1st, 2nd, and reverse.

 

[hear]

Yeah I've usually only rebuilt automatics as well (700r4/4L60e). The thing slowing me down right now is the cost of parts, could probably rebuild a AX15 or NV3550 for around $500. Got a deal on the NSG370 stand and case puller for around $350, if I successfully rebuild this one i'll probably keep all the tools and start to rebuild em for people in the area since most shops wont touch these anymore.

Let’s open a transmission shop.

 

[rlinares40]

Back at it, been sick the past week.

1-2 Synchro Assembly:

• Will replace the whole assembly as the most inner ring looks very worn.
• 1st and 2nd gear will also be replaced as the teeth look to be missing some chunks.

1st synchro

2nd Synchro

2nd Gear

Shift Fork:

• Decided to remove the injection molded plastic (the one that was bad anyways) and take some measurements. Ordered a resin 3D printer and should have a CAD file created by the end of the week. Still doing some research on the specific resin that I will use but I've found some that sound promising with a Heat Deflection Temperature of 240 Degrees Celsius (Roughly 460 Degrees Fahrenheit).
  • According to the manufacturer it can withstand 200 Degrees Fahrenheit for 14 days straight. That's roughly the temp of most running transmissions so it should be good for daily driving.
  • I'm really hoping this works as it would be nice to make the shift fork serviceable and not have to spend $500-800 on a new one. I'll have to dust off the old laptop with Solidworks on it and put this engineering degree to work

 

[freedom_in_4low]

Shift Fork:

• Decided to remove the injection molded plastic (the one that was bad anyways) and take some measurements. Ordered a resin 3D printer and should have a CAD file created by the end of the week. Still doing some research on the specific resin that I will use but I've found some that sound promising with a Heat Deflection Temperature of 240 Degrees Celsius (Roughly 460 Degrees Fahrenheit).
  • According to the manufacturer it can withstand 200 Degrees Fahrenheit for 14 days straight. That's roughly the temp of most running transmissions so it should be good for daily driving.
  • I'm really hoping this works as it would be nice to make the shift fork serviceable and not have to spend $500-800 on a new one. I'll have to dust off the old laptop with Solidworks on it and put this engineering degree to work

any signs that any of the shift forks could be bent?

 

[rlinares40]

any signs that any of the shift forks could be bent?

They passed the eye test but I should probably take a straight edge to them. Would be nice if someone had an example of a bent one!

 

[Claytone]

If you can make those pads, you already have 1 customer.
I'll need to get inside mine at some point.

 

[JMT]

Back at it, been sick the past week.

1-2 Synchro Assembly:

• Will replace the whole assembly as the most inner ring looks very worn.
• 1st and 2nd gear will also be replaced as the teeth look to be missing some chunks.

1st synchro

View attachment 465173

View attachment 465175

View attachment 465176



2nd Synchro
View attachment 465177

View attachment 465178

View attachment 465179



2nd Gear

View attachment 465182

View attachment 465183



Shift Fork:

• Decided to remove the injection molded plastic (the one that was bad anyways) and take some measurements. Ordered a resin 3D printer and should have a CAD file created by the end of the week. Still doing some research on the specific resin that I will use but I've found some that sound promising with a Heat Deflection Temperature of 240 Degrees Celsius (Roughly 460 Degrees Fahrenheit).
  • According to the manufacturer it can withstand 200 Degrees Fahrenheit for 14 days straight. That's roughly the temp of most running transmissions so it should be good for daily driving.
  • I'm really hoping this works as it would be nice to make the shift fork serviceable and not have to spend $500-800 on a new one. I'll have to dust off the old laptop with Solidworks on it and put this engineering degree to work

View attachment 465180

View attachment 465181

The cost of the shift work plus synchros and whatever else I’d need is the reason I’m not interested in doing this myself when I can get a reman for $2200.

 

[rlinares40]

The cost of the shift work plus synchros and whatever else I’d need is the reason I’m not interested in doing this myself when I can get a reman for $2200.

Yeah but you neve know the condition of the Core that was used for the Reman, All in so far with tools/bearing kit/Resin printer I'm at roughly $600ish. if I don't have to replace the shift fork I'll be well under the $2200 mark.

 

[sab]

Yeah but you neve know the condition of the Core that was used for the Reman

+1000

The quality of auto parts has gone completely in the toilet in recent years. I no longer trust remanufacturers. Fraser Engines cost me $8000 and a crap ton of grief over a reman Ford 5.4L in my Expedition. After four tries (yes, four engines/repairs to the engine), I finally gave up trying to get them to make it right. About this time last year, I posted in the "What did you do to your other car?" thread about lifting the body of that Expedition off and replacing that POS engine with a reman from the Ford dealer with a Ford part number. It's finally a reliable vehicle again. I was in a bind and couldn't swap the engine myself at the time, so I paid someone else to do it - out of state. He said he'd make it right if I brought it back to him, but shipping it half-way across the country (several times due to Fraser's incompetence) was cost-prohibitive. If I ever have a catastrophic powertrain failure out of state again, I'll just ship it home and do it myself so that I know it's done properly. Nobody cares about your vehicle like you do!

 

[macleanflood]

My transmission went to a shop in Bend, OR and was in and out of my Jeep 7 times. On try 7 they swapped the back half of the case because the new fork they had put in had a casting defect not allowing it to go into 1st... hitting the case...that back half was cracked. We finally thought it was fixed and I trailered it two hours home. Took it on a longer test drive and $100 worth of MT-90 was all over the back of the Jeep.

Wish I had my original transmission back.

Bought a new AX-15 from Advanced Adapters.

-Mac

 

[sab]

My transmission went to a shop in Bend, OR and was in and out of my Jeep 7 times. On try 7 they swapped the back half of the case because the new fork they had put in had a casting defect not allowing it to go into 1st... hitting the case...that back half was cracked. We finally thought it was fixed and I trailered it two hours home. Took it on a longer test drive and $100 worth of MT-90 was all over the back of the Jeep.

Wish I had my original transmission back.

Bought a new AX-15 from Advanced Adapters.

-Mac

This should probably go in the "What are you doing to your other vehicle today?" thread, but it seems appropriate here. Guess what this weekend's task is? Remove and rebuild the 5 speed in my '98 Impreza. DIY rules!

 

[williambmac]

Let us know how that whitebread brass guide works for ya! My 05 NSG Leaks from the input shaft seal, thinking of swapping it because my second gear synchro is a little worn. I was thinking of getting a later NSG from a JK which has a deeper OD (just a little) and over a decade newer, they share the same input shaft part number, so I assume the bellhousing/front housing is the only thig that needs to be changed ... I'd further assume that a "Wide" ratio liverty trans will work too because it too uses the same input shaft. Just a thought.

I believe you can take the internals from the JK and swap them into the TJ case. I believe that you have to reuse the tj input shaft though. I was toying with this idea a couple months ago. I had a source for a really low mileage JK trans but I hesitated.

 

[Ericshere03]

I believe you can take the internals from the JK and swap them into the TJ case. I believe that you have to reuse the tj input shaft though. I was toying with this idea a couple months ago. I had a source for a really low mileage JK trans but I hesitated.

According the MOPAR, the TJ and JK share the same part number for the front input shaft. And I am willing to bet the rear case is the same or at least the TJ front bell housing/case will mount to the JK back half.

 

[rlinares40]

Well I goofed yesterday and bent the shift fork trying to figure out how to install the Whitbread bronze plate

I found a newer NSG370 sort of close to me that will hopefully have a good shift fork for cheap. Still don't want to spend $800 on a new one...

Anyways, finally had some time to sit down and start making a CAD file for the shift fork pads. I'm sure it will be a lot of trial and error to get the correct sizing but at least with buying the second NSG370 I can check and see if the distances and clearances are the same with the two shift fork pads for reproducibility. Drawing still in preliminary stage.

 

[sab]

I found a newer NSG370 sort of close to me that will hopefully have a good shift fork for cheap. Still don't want to spend $800 on a new one...

Wow, talk about inflation! I bought a spare shift fork assembly last summer (July 2022) for $400 on eBay. That was the cheapest price I found. Seems eBay is now much higher, but there are still deals around cheaper than $800. Here's one at $571 and change (currently):

https://www.moparpartsgiant.com/parts/mopar-fork-assy-manual-transmission~68089073aa.html
The OEMs start raising prices as they get ready to discontinue parts so that when they sell to volume closeout buyers, they can reduce the cost and still make a profit. My bet is that we won't see those available much longer.

 

[freedom_in_4low]

man

Well I goofed yesterday and bent the shift fork trying to figure out how to install the Whitbread bronze plate

I don't know how hard you were beating on it but dang that wouldn't give me warm fuzzies with putting another one back in the Jeep.

Photos of the damage?

 

[rlinares40]

man


I don't know how hard you were beating on it but dang that wouldn't give me warm fuzzies with putting another one back in the Jeep.

Photos of the damage?

either reverse or 1-2 is bent. Brining my straight edge from work today to check.