LS Swap

[89 MJ]

I need taillights... just kidding. 

 

I have decided I might LS swap my MJ because it knocks, misses, has an erratic idle, and leaks oil. 

 

That said, I need one of these: https://www.morris4x4center.com/chevy-v8-v6-to-jeep-ax15-bellhousing-adapter-kit-manual-transmission-168t-flywheel-and-gen-3-engines-aa-712567v.html

 

If you have one for sale, please lmk. 

Thanks

 

Is there anything else I will need (I plan on building motor mounts)?

[derf]

Custom exhaust, probably headers unless you can find manifolds that actually fit.

 

Radiator input/output is backwards between the 4.0 and LS.  There are Chevy conversion radiators out there that bolt right in.

 

Different versions of the LS (Corvette, GTO, Camaro, truck) have different accessory positions and intake manifolds that affect what is easy and what is difficult to swap.  The narrow frame rails of the XJ mean the truck accessories and intake manifolds aren't as easy to swap.  But the engines are cheaper.

 

You'll want to grab everything from the donor that you can.  You'll need to reflash the computer, at least to get rid of the anti-theft cut out.

 

Beyond that, there's tons of write ups on swapping LS engines into almost everything.  Google is your friend.

[Limeyjeeper]

Novak Conversions are a great resource for conversion parts.

[89 MJ]

Thanks!

[omega_rugal]

if you are going LS why keep the AX15? go for a better GM tranny...

[Motorhead X]

Yeah, here is the Novak link for info on trannys:

 

http://www.novak-adapt.com/knowledge/engines/swap-guides/chevy-buick-gm/xj-swap

[89 MJ]

9 hours ago, omega_rugal said:

if you are going LS why keep the AX15? go for a better GM tranny...

 

8 hours ago, bluenotenick said:

Yeah, here is the Novak link for info on trannys:

 

http://www.novak-adapt.com/knowledge/engines/swap-guides/chevy-buick-gm/xj-swap

1. It will live up to the V8

2. It is freshly rebuilt

3. I won’t need different driveshafts or trans crossmember

4. The shifter will line up with the hole in the floor

 

But if I found one of those cheap, I would probably buy it. 

[Pete M]

there are a few LS swap build threads i the Epic Tech subforum.   

[omega_rugal]

7 hours ago, 89 MJ said:

1. It will live up to the V8

 

barely, try to not unleash the LS fury on it...

[89 MJ]

4 hours ago, omega_rugal said:

 

barely, try to not unleash the LS fury on it...

Noted

[DirtyComanche]

Not interested in really reading the thread.

 

Novak sells crap parts and has incorrect tech.  Keep that in mind.

[schardein]

1 hour ago, DirtyComanche said:

Not interested in really reading the thread.

 

Novak sells crap parts and has incorrect tech.  Keep that in mind.

I've had customer service related issues with Novak, and I think there stuff is way overpriced.  But I will say the CJ LS motor mounts are spot on.  Also the NV3550 to Chevy bellhousing adapter plate, and D300 clocking ring worked as advertised.

[derf]

22 minutes ago, schardein said:

I've had customer service related issues with Novak, and I think there stuff is way overpriced.  But I will say the CJ LS motor mounts are spot on.  Also the NV3550 to Chevy bellhousing adapter plate, and D300 clocking ring worked as advertised.

I found Novak to be very helpful when I was doing the 700R4 swap onto the 401 in my J10.  They helped me get the flex plate issues figured out.  The issue was with mixing up 360 measurements with the 401 when making the flex plate they source which put the starter ring out of position.  A few emails and we had everything worked out.

 

And when I did the LS in my old CJ, the Novak mounts were one of the few trouble free parts of that install.

 

I have heard a few people say bad things about Novak but I can't find any real actual examples of their parts being crap.  I'd be interested in seeing some real world examples.

[89 MJ]

Thanks for the input!

[DirtyComanche]

1 hour ago, schardein said:

I've had customer service related issues with Novak, and I think there stuff is way overpriced.  But I will say the CJ LS motor mounts are spot on.  Also the NV3550 to Chevy bellhousing adapter plate, and D300 clocking ring worked as advertised.

 

They make some okay stuff.

 

Their motor mounts for an LS in an XJ/MJ are terrible.  Their tuning is so bad you might as well just not bother.  Their radiator for that swap is a $100 Chinese Ebay radiator that's been repackaged.

[DirtyComanche]

And I'm going to say it now so I don't have to keep saying it.

 

Their tech is wrong.

 

They know 80% and base everything on that.  You need to know more to have the right answer though.  Don't treat what they said as gospel, it isn't, it's the result of not knowing and tailoring the answer to the products they sell.

[Minuit]

In my experience, Novak's tech articles tend to raise more questions than they answer.

[derf]

1 hour ago, DirtyComanche said:

And I'm going to say it now so I don't have to keep saying it.

 

Their tech is wrong.

 

They know 80% and base everything on that.  You need to know more to have the right answer though.  Don't treat what they said as gospel, it isn't, it's the result of mod knowing and tailoring the answer to the products they sell.

Can you give an example or two?

[DirtyComanche]

17 hours ago, derf said:

Can you give an example or two?

 

Sure.

 

Let's look at what they have to say about the NV4500.  The NV4500 isn't a great transmission for all applications, but it is a good choice for some.  Probably not something anyone here wants though, but I've dealt with them a bunch so we'll go with it.

 

Whole article below, no need to read it.

Quote

NV4500 Transmission

The NV4500 or New Venture Gear 4500 is a heavy-duty, manual shift, five-speed overdrive, longitudinally positioned transmission.

History

New Venture Gear was the somewhat unlikely merging of the two manual shift design & manufacturing divisions of General Motors and Chrysler Corp. The Muncie (or Stewart Muncie) division of GM and the New Process division of Chrysler became New Venture and one of the first fruits of this union was the NV4500.

The NV4500 was first released in Chevy / GM trucks from 1992 under GM RPO code MT8 and GM part #12346190. It was introduced into Dodge trucks in 1995. Though it has it roots as the New Process 4500 four-speed beginning as early as 1972 in Dodge trucks, its current incarnation as we know it today is quite different.

Identification

Some objectivity about the NV4500

When the NV4500 was released in the mid-nineties, the 4wd aftermarket and magazines latched on quickly. It was uncritically ballied as the silver bullet and cure-all to any 4wd powertrain problem. Phrases like "Ultimate 4wd Transmission" have been common.

As time and trial have shaken things down, the NV4500 trend is now seen by serious 4wd powertrain aficionados as a prime example of herd instinct. Many individuals have been left unsatisfied with the expense of their transmission investment vs. its benefits. The drawbacks have been:

Gearing: The NV4500 has an initially attractive overdrive gear, but with a low gear of only 6.34:1 (early units) and a gear span of 7.71 and 5.61:1 (later and most common units) and a gear span of 6.96, its position against the heavy-duty four speeds (SM465, T18, SM420 or NP435) is not a lot better. Choosing the right axle ratio and tire size in conjunction with the right transmission is a smarter strategy than using overdrive as a patch to the system.

Size: The length of the transmission, even in its shortest renditions, is too long for many Jeeps, especially those with suspension lifts. The result is u-joint vibration and weakness. The transmission also often requires serious surgery of the body's tunnel to gain back ground clearance.

Expense: The initial flurry to get a 4500 drove up salvage prices that have never really ratcheted back down. New units have been available ranging from $2300. - $2600. Parts availability and expense are surprisingly discouraging in addition to frequent year-to-year parts changes. Expense for NVG to build these transmissions is significant. Overdrive adds serious complications to any gearboxes design and manufacturing.

Strength: Weaknesses in the transmission mainshaft clutch splines and their mating hubs (usually 4th & 5th gears) from fatigue and wear are prominent. The HD four-speeds exhibit consistently better strength & wear characteristics.

Adaptability: Expenses and complications in adapting to either the engine or the transfer case is high. Clutch linkages also prove challenging.

There are too many NV4500's in Jeeps due to an artificial push by aftermarket profiteers and hungry magazine writers looking for a quick story. Actual research and critical analysis by the thoughtful Jeep builder will more often yield the conclusion that a heavy-duty, four-speed transmission (if not an automatic) will produce better on-road & off-road results with significantly less expense.

The NV 4500 is a top loading five-speed transmission with a cast iron case, aluminum top cover and dual PTO ports. It features all helical gears, and is fully synchronized. The NV4500 has a case length of 12.37". 

GM 4wd versions featured an extension housing length of 6.5". There are various other Dodge and GM 4wd and 2wd housings. This housing contains fifth gear and as usual, 2wd style housings are longer.

A unique feature of the NV4500 is its fly-weighted 1st-to-2nd gear synchro assembly, preventing a downshift at excessive revs. Its unique synchro ring composition requires a special synthetic lubricant.

Transfer Case Adaptability

The Chevrolet / GM 4wd version of the NV4500 can be adapted to the Jeep:

Dana 300, 1980-1986

Adaptability to the NP231 transfer case can be acheived when using a Dodge 4wd style tailhousing. However, a change of mainshaft or transfer case input shaft will often be required due to spline count.

Engine Compatibility and Adaptability

The NV4500 is found in GMC & Dodge trucks. The bellhousing pattern for 1993-1994 GM versions is unique from the later (1995-) GM and Dodge units. The 1993 and 1994 Chevy versions have a lower first gear of 6.34:1 and an unsynchronized reverse gear. Transmissions after this period have a higher 5.61 low ratio and reverse gear synchronization.

The input shaft for the 1992 Dodge NV4500 was 19 splines with a 1" diameter, like its predecessor, the Dodge NP435. All GM units and 1993+ Dodge units have 10 splines with 1-1/8" diameter. GM input shafts protrude their usual 6-5/8" while the Dodge units are 7-5/8" long.

Summary

Because of its length, moderate gearing, weight and overdrive, the NV4500 is probably best suited for higher powered Jeeps that require a strong transmission with an overdrive gear. If oversize tires are being used, some Jeeps may never see overdrive and lower axle gearing may be in order to compensate for the NV4500's taller low gear. We are often asked about the durability of the NV4500 vs. the SM420, SM465, T18 and NP435 truck four-speeds. We've spoken with GM and Dodge mechanics that have seen some 4500's come through their facilities for repairs for breakage, but this is most often due to too heavy a truck getting in situations it shouldn't be in. For the purpose of Jeeps, the strength issue is nearly irrelevant due to their agile and lightweight nature. 

Make: New Venture Gear
Length: 18.9" 
Weight: 195 lbs.
Case: Cast Iron
Top Cover: Aluminum
PTO Ports: Both Sides
Gearing: 6.34, 3.44, 1.71, 1, .73, R 6.34 or, 5.61, 3.04, 1.67, 1, .74, R 5.61 

 

 

 

What we need to know before we even get into it.  They don't make adapters for the NV4500.  Hence they aren't interested in saying anything good about it.  The main reason they don't make adapters for it is because you don't need an adapter for many applications you'd likely use it for, so they wouldn't sell very well.  AA also completely beat them to the punch on this and dominated the market for the applications that do need an adapter.

 

I'm not going to pick the whole thing apart, that would take way too long.

 

To break it down by parts:

 

Quote

Gearing: The NV4500 has an initially attractive overdrive gear, but with a low gear of only 6.34:1 (early units) and a gear span of 7.71 and 5.61:1 (later and most common units) and a gear span of 6.96, its position against the heavy-duty four speeds (SM465, T18, SM420 or NP435) is not a lot better. Choosing the right axle ratio and tire size in conjunction with the right transmission is a smarter strategy than using overdrive as a patch to the system.

 

Ah.  You've completely missed the fact that it has ANOTHER gear.  Why would that be important?  Because it means the split between the ratios is less, meaning you can actually keep the engine somewhere near the powerband when shifting.  Granted, the NV4500 has less than ideal splits, but it certainly is way better than the HD 4-speeds they'd love to sell you an adapter for.  And compared with a 3 speed it's night and day.

 

Also it isn't mentioned at that point that the synchronized nature of 1st gear (and reverse on the later versions) means you can shift into those rather useful gears as hell of a lot easier on the fly.

 

Quote

Size: The length of the transmission, even in its shortest renditions, is too long for many Jeeps, especially those with suspension lifts. The result is u-joint vibration and weakness. The transmission also often requires serious surgery of the body's tunnel to gain back ground clearance.

 

It's not 1986 anymore.  We aren't building 82" wheelbase Jeeps.  Yes, it's big, no, it's not that big.  It is the same height as the SM420/465 or NP435 that you're going to tout as being the better option.  If you had to mod your trans tunnel for the NV4500, you'd have to for one of those.

 

Quote

Expense: The initial flurry to get a 4500 drove up salvage prices that have never really ratcheted back down. New units have been available ranging from $2300. - $2600. Parts availability and expense are surprisingly discouraging in addition to frequent year-to-year parts changes. Expense for NVG to build these transmissions is significant. Overdrive adds serious complications to any gearboxes design and manufacturing.

 

There was one on Marketplace for $250 a few days ago.  I paid $600~ (converted) for one.  They're common now.  Not rare.  You can still buy them new, and that actually is a plus.  Good luck buying any transmission new for much less money.

 

Quote

Strength: Weaknesses in the transmission mainshaft clutch splines and their mating hubs (usually 4th & 5th gears) from fatigue and wear are prominent. The HD four-speeds exhibit consistently better strength & wear characteristics.

 

No, just no.  Behind a 1000ft-lb diesel they break, yes, behind a gasser they don't...   They imply that a NP435 or SM465 would actually survive that reliably and for as long.  They won't.  It's been proven.  Plus there is updated parts to fix these issues if you are using them in that application.  But why mention that?

 

Quote

Adaptability: Expenses and complications in adapting to either the engine or the transfer case is high. Clutch linkages also prove challenging.

 

Again, no.  Here is what AA sells to bolt it to a Jeep engine: https://www.advanceadapters.com/products/712553--dodge-nv4500-to-jeep-258--v8-bellhousing-adapter-plate-kit/

They want $285 for it.  Yes pilot bushings suck (Novak uses them too), but $285 is in no way expensive or complicated.  Would use stock clutch linkage.  I have no idea what they think is so hard about this.

 

You can then bolt a Jeep Tcase to it if you swap the input gears.  Again, what is so hard or expensive about that?  Likewise AA has a bunch of fairly inexpensive adapters to put just about anything else behind it; I used their NP205C adapter with one in my plow truck.

 

Quote

Engine Compatibility and Adaptability

The NV4500 is found in GMC & Dodge trucks. The bellhousing pattern for 1993-1994 GM versions is unique from the later (1995-) GM and Dodge units. The 1993 and 1994 Chevy versions have a lower first gear of 6.34:1 and an unsynchronized reverse gear. Transmissions after this period have a higher 5.61 low ratio and reverse gear synchronization.

The input shaft for the 1992 Dodge NV4500 was 19 splines with a 1" diameter, like its predecessor, the Dodge NP435. All GM units and 1993+ Dodge units have 10 splines with 1-1/8" diameter. GM input shafts protrude their usual 6-5/8" while the Dodge units are 7-5/8" long.

 

Wrong.  They got to 1-1/4" input shafts in later production.  That is relevant because the 10 spline 1-1/8" is the same as a Jeep clutch, but the later 1-1/4" isn't.

 

Here is the LuK clutch with specs for such a variant: https://www.rockauto.com/en/moreinfo.php?pk=4696164&cc=1377569&jsn=1903&jsn=1903

 

Quote

Make: New Venture Gear
Length: 18.9" 
Weight: 195 lbs.
Case: Cast Iron
Top Cover: Aluminum
PTO Ports: Both Sides
Gearing: 6.34, 3.44, 1.71, 1, .73, R 6.34 or, 5.61, 3.04, 1.67, 1, .74, R 5.61 

 

Oh, so earlier on you said they have multiple gearing options.  Then you don't include it here?   Length also varies depending on input variant.

 

 

Anyways, my point is that they present "factual tech" with a pretty serious slant to their product line.  There is some more blatant errors in some other the other stuff, while the NV4500 piece is more an opinion piece.

[DirtyComanche]

Also, for the OP,  I'd pick up a GM NV3500 over an adapter to an AX-15.  Then find a suitable GM tcase, a 241 from a 4L80E truck would probably work (don't quote me, I think the NV3500 used a 27 spline output actually and the 4L80E uses a 32, you may have to steal the input gear from whatever came with the transmission).  The NV3500 is a better tranny than the AX too, snychro'd is all gears and meant to survive behind a 4.8L (wasn't offered with the 5.3L but would handle it fine.  A 6.0L and abuse would not likely end well).  There's some potential issues with this setup but they're all easy to solve.

 

Factory everything that way.  You want a speed sensor and a hi-low switch too, hence the GM tcase, as the "LS" tunes need correct VSS input to function correctly.  Most hack tuners delete the VSS input (Novak does this) and it will quite likely produce some odd running issues when the vehicle comes to a stop or is moving slowly with minimal throttle input.

 

The more factory parts that were mostly meant to be bolted together that you use the better it will be in the long run.

[derf]

3 hours ago, DirtyComanche said:

 

Sure.

 

[snip]

 

Anyways, my point is that they present "factual tech" with a pretty serious slant to their product line.  There is some more blatant errors in some other the other stuff, while the NV4500 piece is more an opinion piece.

 

Yeah, that certainly is out of date at best.  I doubt they've updated many of their articles in years.

 

And yes, you never want to fully trust a company that has a vested interest in selling you something.  Always check multiple sources.

 

What would be a better resource for things like that?

[DirtyComanche]

9 minutes ago, derf said:

What would be a better resource for things like that?

 

I don't know.  Google.  Look at the P/Ns on Rockauto.  Ask people that have done things.  Etc.  Pirate has a lot of good info if you're willing to look, but some of it is dated now.   Most of the time you can find enough basic info about something to make a list of further questions and either go ask somewhere or slowly Google them away.

 

The OP of this thread should read this from start to finish: https://www.pirate4x4.com/forum/jeep-hardcore-tech/735270-5-3-jeeps.html

 

It's interesting because the understanding of the swaps evolved a lot in the 11 years.