Project “Tomahawk”

[ghetdjc320]

I had an 05 nsg370 on my tj rubicon. It has an integral bellhousing so I didn’t consider it a swap candidate. I’m sure it would hold up to most 4.0 based strokers though. Good overall tranny. Early models had a reverse gear recall

[Limeyjeeper]

On 7/18/2024 at 9:31 PM, Torq_Shep said:

Is there anyone building the 6 speed NSG370 or are those not even worth a discussion? 

I had one in my LJ. Very poor German truck transmission and it had a shift throw that was insanely long. B&M makes a short throw shifter which helped a bit. Mine only had around 35k on it and it was impossible to shift quickly. The syncro's were really weak. A Tremec TKX or a TR4050 would be the best choice. However, the old AX15 is a pretty stout trans too.

[ghetdjc320]

7 hours ago, Limeyjeeper said:

I had one in my LJ. Very poor German truck transmission and it had a shift throw that was insanely long. B&M makes a short throw shifter which helped a bit. Mine only had around 35k on it and it was impossible to shift quickly. The syncro's were really weak. A Tremec TKX or a TR4050 would be the best choice. However, the old AX15 is a pretty stout trans too.

Curious to know, would you still go ax15 for your build if you did it again? 

[Limeyjeeper]

On 7/22/2024 at 6:38 PM, ghetdjc320 said:

Curious to know, would you still go ax15 for your build if you did it again? 

I would probably do an auto. The LS torque curve doesn't lend itself very well to a 5 speed. Or I would go with 3.73 gears nor 3.55. The LS makes its power once you get over 2.5k revs. The LS1 intake doesn't help that moves up the torque and power curve. A good tune might fix some of it too. Still haven't got around to getting the LS on a dyno.

[ghetdjc320]

55 minutes ago, Limeyjeeper said:

I would probably do an auto. The LS torque curve doesn't lend itself very well to a 5 speed. Or I would go with 3.73 gears nor 3.55. The LS makes its power once you get over 2.5k revs. The LS1 intake doesn't help that moves up the torque and power curve. A good tune might fix some of it too. Still haven't got around to getting the LS on a dyno.

Good to know. I’m running 4.56 gears with my metric 33’s. I’ve been contemplating cam swapping this engine to a low rpm torque cam like maybe a btr truck stage 1 or something. Never really looked into an auto swap though. Was just trying to get close to the same rpm ranges as the C5 with the T56. Seems like an auto is a more economical option though. 

[ghetdjc320]

An interesting tidbit of tech from Novak regarding LS swaps in MJ/XJ platforms: ideal engine slope angle is 4* down towards the rear but up to 7* is considered acceptable. This can mostly be adjusted at the transmission mount. I’ve noticed that between the Novak engine and tranny mounts and the quick draw bellhousing, the ax15 can sit quite high in the trans tunnel. I was able to remove some unneeded tabs on the NP242 and tuck it up also nice and tightly. I plan on fitting the Barnes XJ skid plate on it at some point and will report back with the fitment (still a few months away).

[Comanche SS]

12 hours ago, ghetdjc320 said:

An interesting tidbit of tech from Novak regarding LS swaps in MJ/XJ platforms: ideal engine slope angle is 4* down towards the rear but up to 7* is considered acceptable. This can mostly be adjusted at the transmission mount. I’ve noticed that between the Novak engine and tranny mounts and the quick draw bellhousing, the ax15 can sit quite high in the trans tunnel. I was able to remove some unneeded tabs on the NP242 and tuck it up also nice and tightly. I plan on fitting the Barnes XJ skid plate on it at some point and will report back with the fitment (still a few months away).

The angle desired from what I read is not so much engine operation limited, but rather U-joint limited. Begs the question, with your "uptight" NP242, what are your driveshaft angles looking like?

 

[ghetdjc320]

On 7/31/2024 at 12:30 AM, Comanche SS said:

The angle desired from what I read is not so much engine operation limited, but rather U-joint limited. Begs the question, with your "uptight" NP242, what are your driveshaft angles looking like?

 

I’ll have to measure pinion angle once the front once castor is set. Ideally the pinion will be at zero. The actual driveshaft angle should be pretty decent with the HP front. When I first test fit everything, the drivetrain angle was about 6-7 degrees. Ultimately I’d say the transmission was able to be raised up around 1.25” and maintain a really nice uniform gap all around once the tcase housing was cleaned up. Essentially did a tummy tuck. I’d imagine the smaller np231 wouldn’t have this issue or one could just run the drivetrain angle as it sits but your front output yoke would be angled up a bit more than ideal.

Keep in mind that I still have a tiny bit of factory rake 
 

[ghetdjc320]

The time is approaching to get this project completed. So here's what's on the horizon:

 

Transmission: Picked up an AX15 rebuild kit for my original tranny I'm using along with some Marlin Crawler upgrades. The rebuild kit has all Japanese bearings and synchro king synchronizers. Also ordered the updated 5th gear and hub set from Aisin which has some sort of improved design. I'll do a comparison once I get the old one out to see what they did. 

 

Engine: picked up a full set of genuine GM Performance top end gaskets, lifter trays, head bolts, and LS7 trays. Also picked up the latest Che bronze rocker trunnions. Still undecided if I want to do any power mods. 

 

Axles: Ordered a new front and set of ARB's along with their black diff covers. Already have the full set of 4.56 gears for these axles. Also will be adding Artec brackets to the front D30. Will have to see how extensive this goes. 

 

Rear bumper: Settled on the dirtworks DIY manta bumper and also the hitch. Wanted the DIY setup as I wanted to customize some features of the bumper. 

 

Audio: Picked up a class A/B 4 channel amp which I'm going to use to power the front door 5.25's and the dash mounted tweeters and I'll be using the rear channels in 2ohm to drive a pair of 6.5" subs in the b panels and plan on tuning them as mid-bass woofers (around 60-150hz range). I have some thoughts on how I want to install those but let's see what happens. If they sound good enough, I'll run them as my subs. If the are just going to be used to fill in the mid bass area, I'll sun a dedicated separate sub. 

 

Misc: picked up a whole bunch of odds and ends. Oracle rear tail lights with tinted lenses, Holley low-mount ac kit, exhaust components etc. 

[89 MJ]

Glad to see this thread getting updated

[ghetdjc320]

6 hours ago, 89 MJ said:

Glad to see this thread getting updated

 Me too. Truly have to have this finished within about 4 months. Should be plenty of progress starting in a few weeks. 

[watchamakalit]

Oh boy,. It's getting exciting in here now.....

 

I really enjoyed watching the last build and am eager to watch this one.

[Comanche SS]

On 12/9/2024 at 6:36 PM, ghetdjc320 said:

The time is approaching to get this project completed. So here's what's on the horizon:

 

Transmission: Picked up an AX15 rebuild kit for my original tranny I'm using along with some Marlin Crawler upgrades. The rebuild kit has all Japanese bearings and synchro king synchronizers. Also ordered the updated 5th gear and hub set from Aisin which has some sort of improved design. I'll do a comparison once I get the old one out to see what they did. 

 

Engine: picked up a full set of genuine GM Performance top end gaskets, lifter trays, head bolts, and LS7 trays. Also picked up the latest Che bronze rocker trunnions. Still undecided if I want to do any power mods. 

 

Axles: Ordered a new front and set of ARB's along with their black diff covers. Already have the full set of 4.56 gears for these axles. Also will be adding Artec brackets to the front D30. Will have to see how extensive this goes. 

 

Rear bumper: Settled on the dirtworks DIY manta bumper and also the hitch. Wanted the DIY setup as I wanted to customize some features of the bumper. 

 

Audio: Picked up a class A/B 4 channel amp which I'm going to use to power the front door 5.25's and the dash mounted tweeters and I'll be using the rear channels in 2ohm to drive a pair of 6.5" subs in the b panels and plan on tuning them as mid-bass woofers (around 60-150hz range). I have some thoughts on how I want to install those but let's see what happens. If they sound good enough, I'll run them as my subs. If the are just going to be used to fill in the mid bass area, I'll sun a dedicated separate sub. 

 

Misc: picked up a whole bunch of odds and ends. Oracle rear tail lights with tinted lenses, Holley low-mount ac kit, exhaust components etc. 

Let me know when to cruise by again....This time I *think* I can bring the LS3 MJ up there and take you for a ride...youll probably want some power upgrades once you ride in it! Havent taken it that far yet, but excited to show you, and help get your MJ wrapped up.

[ghetdjc320]

4 minutes ago, Comanche SS said:

Let me know when to cruise by again....This time I *think* I can bring the LS3 MJ up there and take you for a ride...youll probably want some power upgrades once you ride in it! Havent taken it that far yet, but excited to show you, and help get your MJ wrapped up.

Sounds great! 

[ghetdjc320]

[watchamakalit]

1 hour ago, ghetdjc320 said:

What a tease.....

[ghetdjc320]

Engine is out. Transmission has it own workspace prepped for the upgraded parts and rebuild. I’ll need to add the washers to the pivot ball side of the throw out bearing fork to space it a little closer to the clutch. Also marked the offending areas of the quick draw bell housing where it makes contact with the firewall. Going to remove some material there and make a flat surface. Possibly by welding in a plate. 

[Comanche SS]

12 hours ago, ghetdjc320 said:

Engine is out. Transmission has it own workspace prepped for the upgraded parts and rebuild. I’ll need to add the washers to the pivot ball side of the throw out bearing fork to space it a little closer to the clutch. Also marked the offending areas of the quick draw bell housing where it makes contact with the firewall. Going to remove some material there and make a flat surface. Possibly by welding in a plate. 

I had a buddy contact quickdraw to ask about cutting the bellhousing...and in a roundabout way, the quickdraw guys say cut it out, and no need to plate unless you desire, if you just cut a small window, he claims itll still be strong enough for what we are doing.

Luckily, I didnt have to cut mine and thus a non issue

 

[ghetdjc320]

7 hours ago, Comanche SS said:

I had a buddy contact quickdraw to ask about cutting the bellhousing...and in a roundabout way, the quickdraw guys say cut it out, and no need to plate unless you desire, if you just cut a small window, he claims itll still be strong enough for what we are doing.

Luckily, I didnt have to cut mine and thus a non issue

 

Good to know. I’m going to measure the thickness of the material and see how much could be safely ground before I slice it open for a plate. If it doesn’t have to be structural and if the material is thick enough, I may make an actual access plate. 

[ghetdjc320]

Engine tore down to a short block. Doing a full cleaning and inspection. Crosshatching on the cylinder walls is fully visible. Everything looks great overall. Removed any carbon buildup. 
 

 

[ghetdjc320]

Tapped the passenger side coolant port to 3/8 npt to use a decent quality 3/8 to 1/8 reducer to run the Jeep gauge sensor. Lots of cleanup and assembly. 100% genuine GM parts used, none of those copy lifters, trays, gaskets etc. Also am swapping to an ls2 water pump as it looks much cleaner under the hood vs that giant ls1 water pump pulley. Awaiting a replacement set of Che bronze trunions that will complete the heads. Went with remflex header gaskets also to ensure zero leaks on the Sanderson headers. Coated all new parts and cylinders/pistons/valves in a light coating of assembly lube. Tranny work coming up next. The last picture is of the ax15 5th gear upgrade kit. Since I don’t have the original gear out yet I can’t say what the difference is but I’ll document it and compare some of the upgrades with the original parts. 

[ghetdjc320]

Rear half of the case disassembled 

[ghetdjc320]

Interesting project. Never delved into the ax15 this far. Was able to do a full rebuild and upgrade to the newer synchros, Marlin HD thrust washer and billet retainer plate. Fun project. Tested all the gears and it shifts great. 
 

 

[Eagle_SX4]

Good job. They are quite easy to rebuild if you have access to a press. What is the verdict on the 5th gear upgrade? Any differences you could see?

[ghetdjc320]

2 hours ago, Eagle_SX4 said:

Good job. They are quite easy to rebuild if you have access to a press. What is the verdict on the 5th gear upgrade? Any differences you could see?

I’ll be installing it tomorrow. I think the difference is with the 5th gear shift hub or possibly the blocking rings “slipper clutch” but don’t know for sure yet.
 

I ran into the same issue that many people do when rebuilding the ax15. The new 3-4th gear blocking rings have different shaped teeth than the originals. I see a lot of people reuse originals as you can’t really find the “house” shaped teeth versions for 3-4 rings. You’ll notice a comparison pic of the new vs old above. Supposedly, the adjustment in tooth design was designed to improve 4-3 downshifts and 3-4 upshifts. I researched it quite thoroughly and others have used the newer “ramped” style tooth blocking rings on the older synchros with no issue. It doesn’t seem like it would present an issue since ultimately, the tooth width is the same at the base, the blocking rings will still engage the slider teeth and the slider and synchro still have the same pattern.