fcjunkie Posted March 5, 2012 Share Posted March 5, 2012 New to the group here and excuse me if this has been covered before but has anyone ever installed a semi-modern drivetrain into their MJ’s? My thoughts ran along the lines of a 2005-06 TJ Wrangler 4.0 with the 6-speed manual transmission. I plan on building a Comanche from scratch and will use a rust free short bed as a base unit. This would be my daily driver. We own a 2006 LJ Rubicon with the 6-speed and even though it doesn’t really offer a better OD gear for mileage, when you drive one they always seem to be in the optimal power band. My thoughts were 4.10 gears with 32” tires and a 3 ½” to 4 ½” lift. I saw a MJ a while back from Canada that was on eBay that had the 6-speed, so I know it has been done. I’m just wondering if anyone has grafted a late model TJ setup into their MJ and could pass along any tips on what all is needed for such a conversion? (ie. Motor mounts, computer, harness, gas pedal?) Thanks in advance and this is a really great forum!!! Link to comment Share on other sites More sharing options...
Fezzik Posted March 5, 2012 Share Posted March 5, 2012 http://www.novak-adapt.com/knowledge/nsg370.htm According to that site, there is a bell housing for a4.0 and it is compatible with a 231 23 spline. I don't know if the measurements would work for the MJ, but they are listed on the site. where you are building one from scratch you may need to do a custom crossmember and drive shaft. Link to comment Share on other sites More sharing options...
87Warrior Posted March 5, 2012 Share Posted March 5, 2012 Avoid the 05/06 4.0 like the plague. Worn out tooling at Chrysler was used with these motors and they are known to be very troublesome, even if you ignore the OPDGA failures. Not to mention your engine accessories will require custom mounts. The 6 speed replaced the NV3550 Jeep started using in 2000. Using a TJ transfercase will require you to clearance the floor pan a little on your truck. If you want to go this route, check out the numerous 97+ XJ conversions. If you find a 00/01 XJ you can utilize the distributor-less ignition system. Here is a start: viewtopic.php?f=9&t=32505 Link to comment Share on other sites More sharing options...
fcjunkie Posted March 5, 2012 Author Share Posted March 5, 2012 So the AX-15 started out with the TJ line and then the NV 3500 5-speed in 2000 followed by the NSG370 6-speed in 2005. In theory the 6-speed should fit to the HO 4.0 offered in the 1991-92 MJ’s. Still looking for the right MJ to build from but I have time on my hands right now. Really like to find a clean one in the next three months. I have the facilities at my home to deal with a restoration/repower. Link to comment Share on other sites More sharing options...
fcjunkie Posted March 5, 2012 Author Share Posted March 5, 2012 If you want to go this route, check out the numerous 97+ XJ conversions. If you find a 00/01 XJ you can utilize the distributor-less ignition system. Here is a start: viewtopic.php?f=9&t=32505 Most Excellent!! Something to chew on! Thanks for getting me pointed in the right direction. There's sooo much information on this site that a new guy can tend to get lost in the fog at times. Many thanks :thumbsup: Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 5, 2012 Share Posted March 5, 2012 the block has different casting mounts, so it wouldn't even work. put the trans on an older motor 2001 and older. Link to comment Share on other sites More sharing options...
xjrev10 Posted March 6, 2012 Share Posted March 6, 2012 What if any kind of electric crap does the nsg370 got? What about the speedo cable?*** I'm thinking (doing research) on swapping a nsg370 behind my renix. ***Guess that might be a question for a different thread. Going from a 2wd pukey, to Nsg370 with a 231/242. Does the mechanical speedo from a older case swap into a new(er) case? Link to comment Share on other sites More sharing options...
bighause Posted March 6, 2012 Share Posted March 6, 2012 Then again the 2000 and 2001 4.0's are famous for the heads cracking. They had the 0331 casting on the head Link to comment Share on other sites More sharing options...
87Warrior Posted March 6, 2012 Share Posted March 6, 2012 Then again the 2000 and 2001 4.0's are famous for the heads cracking. They had the 0331 casting on the head Yup, but you can use the head from an 03-06 4.0 Link to comment Share on other sites More sharing options...
Incommando Posted March 6, 2012 Share Posted March 6, 2012 You will like that tranny. I have on in my KJ. Link to comment Share on other sites More sharing options...
xjrev10 Posted March 7, 2012 Share Posted March 7, 2012 Then again the 2000 and 2001 4.0's are famous for the heads cracking. They had the 0331 casting on the head This is more popular on the internet then in the rear world IMHO. Ive had 3 '00 engines, no problems. All had over 140k. Link to comment Share on other sites More sharing options...
Geonovast Posted March 7, 2012 Share Posted March 7, 2012 Where in Missouri are you? I've somewhat recently seen a very shiny red and white FC going through Springfield. Link to comment Share on other sites More sharing options...
fcjunkie Posted March 7, 2012 Author Share Posted March 7, 2012 I know the truck if it's a FC-150, I used to own it. :fs1: I'm about 50 miles west of St. Louis, just a stone's throw from the Daniel Boone home, but my Tour Jeep will be heading through Springfield in a few weeks as we make the trek to the FC Roundup in Phoenix. With 4.88 gears and 30" tires it will be riding on the trailer though! Link to comment Share on other sites More sharing options...
bighause Posted March 8, 2012 Share Posted March 8, 2012 The 01 XJ I owned had the head crack on cyl 3 and it had the 0331 head I've owned 6 4.0's with high miles and the 01 was the only one that I had any trouble with Link to comment Share on other sites More sharing options...
mvusse Posted March 8, 2012 Share Posted March 8, 2012 Then again the 2000 and 2001 4.0's are famous for the heads cracking. They had the 0331 casting on the head This is more popular on the internet then in the rear world IMHO. Ive had 3 '00 engines, no problems. All had over 140k. One acquaintance of mine is currently in the middle of a head swap, another just did one last year. Both 2000 models, both due to a cracked head. A third one with a 2000 had a piston come apart, he ended up building a 4.6 stroker to replace the old engine. Link to comment Share on other sites More sharing options...
Blue XJ Posted March 8, 2012 Share Posted March 8, 2012 What if any kind of electric crap does the nsg370 got? What about the speedo cable?*** I'm thinking (doing research) on swapping a nsg370 behind my renix. ***Guess that might be a question for a different thread. Going from a 2wd pukey, to Nsg370 with a 231/242. Does the mechanical speedo from a older case swap into a new(er) case? Speedo cable goes to the transfer case, not the trans. Link to comment Share on other sites More sharing options...
xjrev10 Posted March 9, 2012 Share Posted March 9, 2012 What if any kind of electric crap does the nsg370 got? What about the speedo cable?*** I'm thinking (doing research) on swapping a nsg370 behind my renix. ***Guess that might be a question for a different thread. Going from a 2wd pukey, to Nsg370 with a 231/242. Does the mechanical speedo from a older case swap into a new(er) case? Speedo cable goes to the transfer case, not the trans. see what i I last wrote. saying 'case' means transfer case in my vocab. :cheers: Link to comment Share on other sites More sharing options...
xjrev10 Posted March 9, 2012 Share Posted March 9, 2012 Then again the 2000 and 2001 4.0's are famous for the heads cracking. They had the 0331 casting on the head This is more popular on the internet then in the rear world IMHO. Ive had 3 '00 engines, no problems. All had over 140k. One acquaintance of mine is currently in the middle of a head swap, another just did one last year. Both 2000 models, both due to a cracked head. A third one with a 2000 had a piston come apart, he ended up building a 4.6 stroker to replace the old engine. I have a coworker with a 01 WJ that is going through coolant at a pretty good rate. I'm thinking this may be the first problem one I have seen. I wouldnt be scared of a 2000-01 with over 100k. What my point is that alot of folks think EVERY 00-01 head is going to crack cuz they "read it online." Link to comment Share on other sites More sharing options...
terrawombat Posted March 9, 2012 Share Posted March 9, 2012 I've personally seen three 0331 head crack failures - two my own and one on my cousins '01 - so I can vouch it is NOT just an internet story. As for the '05/'06 4.0L engines being junk, that's the first I've really heard of that. My GF has an '06TJ with the 6-speed in it. Interesting transmission with a completely useless 1st gear for the pavement - took a while to pound it into her head that you can start the vehicle in 2nd gear and not hurt it....women.... Link to comment Share on other sites More sharing options...
xjrev10 Posted March 9, 2012 Share Posted March 9, 2012 I've personally seen three 0331 head crack failures - two my own and one on my cousins '01 - so I can vouch it is NOT just an internet story. As for the '05/'06 4.0L engines being junk, that's the first I've really heard of that. My GF has an '06TJ with the 6-speed in it. Interesting transmission with a completely useless 1st gear for the pavement - took a while to pound it into her head that you can start the vehicle in 2nd gear and not hurt it....women.... Interesting. I wonder if the NV3550 is the same with the first gear thing. Would be nice for plucking a boat out of the lake ie. the low first gear. Link to comment Share on other sites More sharing options...
carnuck Posted March 9, 2012 Share Posted March 9, 2012 I'm more of a Luddite. Going with heavier, stronger older tech. The EFI is nice though. Link to comment Share on other sites More sharing options...
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