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Discussion Starter #1
Hello all,
I'm new here so I apologize if this is a dumb question. I'm looking to do a hemi swap on my 08 6 speed rubicon, I want to keep a manual and I know the stock trans won't work and the Getrag 238 seems to be the trans of choice, but seems scarce and expensive. Here is the question, is a hemi with a TR660 (t-56) an option? I know these transitions never came equipped on a 4x4 but it looks like Rockland Gear makes an adapter to fit it to a transfer case and the trans will handle plenty of power. Has anyone tried this? if so what is involved in making it work? Thanks.
 

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Wish I had an answer for you. I'm interested as well. I've been considering a V8 swap for some time, but moving to an auto is a no-go for me.
 

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I think to do it right, you'd want to have some custom gearing to get a lower first and 6th gear, at a minimum, because the TR6060 was designed for car tire sizes. As you mentioned RSG, they do have their "tranzilla" and adapters to make it work.

Robbie at Motech has done LS swaps using the RSG manual trans. Check their Youtube page for ideas on the crossmember mods required, the RSG TC adapter, shift tower mod they did in-house (I think), etc...

Unfortunately, when all is said and done, the RSG route would probably cost significantly more than the G238 in both $$$ and time. You'll surely have a stronger transmission; but I haven't seen any documented problems with the Hemi / G238. I have my G238 costs detailed in my swap thread. I can say that RSG gave me a ballpark estimate (two years ago) that was almost 30% more than I paid for a brand new G238.

On the other hand, I'm sure we'd all love to see someone detail a Hemi / RSG swap on here. Good luck!
 
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We have done the rockland TR6060 4x4 behind a LS in a JK.
Several issues.
First its very expensive.
Second, gearing in the trans is more set up for a lighter car. its not geared very low at all.
Third, it ends up being very long. with the tcase adapter they run it makes the overall trans really long and puts the Tcase a lot further back. Drive shaft - crossmember issues.
Lastly, you will need a custom shifter base thats adjustable to move the shifter as far forward as possible to fit the stock opening.
 

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Discussion Starter #5
Thanks for the input, good point about the gear ratio's I was thinking of the fitment and didn't consider that. Looks like The Getrag is the way to go.
Another question, I'm sure it's been asked many times before so my apologies, but any preference on donor vehicle? truck vs. car? More than likely going with the 5.7 (unless I find a good deal on a 6.1) I am looking for a lower mileage donor so it will likely have vvt and dod. and mine is a 08 so it never had any of this. Maybe i'm better off rebuilding a older non vvt engine?
 

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With a manual, you'll want to find a non-MDS engine. You can find them on any vehicle that had a manual transmission, and also the Ram 2500 / 3500 auto or manual. The MDS engines will work, but you'll have the collapsible lifters that may cause trouble over time.

I'd also recommend going with a 2009+ Ram engine because the alternator sits up high (better position for muddy rides).

FWIW, if I were to do it again, I'd either buy a remanufactured short block, or buy a junked engine and have the short block professionally rebuilt. Build the long block myself so I know it's done right. Upgrade the pushrods and rocker assys. as well.

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With a manual, you'll want to find a non-MDS engine. You can find them on any vehicle that had a manual transmission, and also the Ram 2500 / 3500 auto or manual. The MDS engines will work, but you'll have the collapsible lifters that may cause trouble over time.

I'd also recommend going with a 2009+ Ram engine because the alternator sits up high (better position for muddy rides).

FWIW, if I were to do it again, I'd either buy a remanufactured short block, or buy a junked engine and have the short block professionally rebuilt. Build the long block myself so I know it's done right. Upgrade the pushrods and rocker assys. as well.

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Did you have issues with a low mile pullout?
 

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Did you have issues with a low mile pullout?
Yup. In short, and despite taking all precautions prior to purchase, the engine looked like the last owner did the Cannonball Run with it lol. Oil coating in several exhaust ports and dubious leak down test results (that I made) lead to trip to machine shop. Shop said four of the oil seal rings weren't touching the cylinder walls (bad factory assembly?). Shop did a light hone, replaced main/rod bearings and installed Total Seal Gapless ringset. Got the engine home and found they used two right-side aftermarket (Cometic) head gaskets. Decided to delete the MDS lifters (used Melling JBK-7521, OEM supplier) while also correcting the head gaskets (back to stock SRT). Saw that the machine shop did not clean off the old head gasket residue from the block. Also found six scratched pushrod tips and associated rocker cups (from previous owner's use). Also found the stock pushrods were all short and not straight. Went with Manton 3/8" x 0.095" wall pushrods (length and straightness much improved). Replaced rocker assemblies with a revised set (new OEM part number) that has chamfered oiling holes in the shafts.

This engine sounds absolutely awesome, ZERO abnormal valve train noises, not a hint of a tick anywhere. Smooth like my wife's Honda 3.5. BUT, it took a rebuild and several corrections to get there. The same results can be had cheaper with an old engine and plan for rebuild from the start. Bypass any crappy factory assembly issues and upgrade a few internals to have a better-than-new engine.

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Discussion Starter #9
Thanks, I managed to find a good deal on a used G238 and will go through and freshen it up. Now the search for the engine, I agree with finding a non MDS engine, I have found a couple of 6.4 2500/3500 but they still seem to have the MDS did yours have it? if not what year did they start using it?
 

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Thanks, I managed to find a good deal on a used G238 and will go through and freshen it up. Now the search for the engine, I agree with finding a non MDS engine, I have found a couple of 6.4 2500/3500 but they still seem to have the MDS did yours have it? if not what year did they start using it?
Hmm I hadn't heard that they started putting MDS in the HD hemis. I'd guess anything up to 2013 would be non-MDS. Looks like the online dealer databases have the 2500's as non-MDS. Here's factorychryslerparts with a non-mds assembly fitment list:



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My 6.4 came from a Challenger, but I swapped out the timing cover / accessories for the 5.7 truck hemi version. Also had to do the mds delete because the Challenger was an auto (replaced lifters, used a non-mds cam phaser harness, and swapped solenoids for aluminum plugs but did not replace the camshaft).

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Discussion Starter #12
So I picked up a used 6.4 from a low mile manual car so no MDS and found a G238, did a leakdown test and it looks good so I'm going to try it as is. I am leaning towards the Jeep Speed Shop swap kit (I welcome any input here) but I have a couple of questions.
First, the flywheel clutch combo. It seems like people have used the Dakota setup and some the ram 2500/5.7 setup, just wondering what is the difference?

Second will the stock driveshafts work with this setup? I took a rough measurement of the 6.4/G238 combo and it seems slightly longer than existing.
 

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So I picked up a used 6.4 from a low mile manual car so no MDS and found a G238, did a leakdown test and it looks good so I'm going to try it as is. I am leaning towards the Jeep Speed Shop swap kit (I welcome any input here) but I have a couple of questions.

First, the flywheel clutch combo. It seems like people have used the Dakota setup and some the ram 2500/5.7 setup, just wondering what is the difference?



Second will the stock driveshafts work with this setup? I took a rough measurement of the 6.4/G238 combo and it seems slightly longer than existing.
No complaints here; just facts. I ordered my kit from JSS, over the phone, around March 20, 2017. I received the last of three shipments from them around November 6, 2017. If you go with them, then try to stick to the scope of the kit as much as possible. I wasn't happy with several of the kit parts, and only ended up using their frame brackets, transmission cross member plates, and battery tray. Also used a harness and pcm from them but in the end, they couldn't make their pcm work properly for this setup, so they had Chris at Hotwire Auto send me one of his. More on the electrical stuff below.

Recommend weld-in engine brackets. The bolt-in brackets use the original engine frame brackets, so the engine probably can't be moved around much to correct any fitment issues (think shift tower). There are a few businesses that sell them.

Recommend custom exhaust headers done after the engine is in place. The 6.4 will leave HP / TQ on the table if you use the GC log manifolds. Lots of extra work to make the stock SRT manifolds fit but obviously it can be done. Go local and have a shop fab a set on your jeep for best results. I think that would be ~1200 or so.

Highly recommend getting the air inlet out of the engine compartment. The stock SRT intake manifold leaves few options, but you can get a modified version to get the air inlet back over to the passenger (right) side. The modified intake (and also something like Edelbrock) is very $$$$, but the alternative is a vvt truck manifold (2009+ 5.7) and it costs almost as much after buying the truck timing cover and accessories. For my first couple of engine runs in the driveway, I had the hood up with the snorkel removed, about 80 degrees ambient; my intake air temp went all the way up to 144 degrees in 15 minutes.

I'm using stock flywheel and Centerforce clutch for the 2005-2009 Dakota 4.7. Not enough miles yet but so far so good (1500 miles). I do have a subtle rattling sound at idle / neutral but not sure if it's the clutch or something else.

Stock driveshafts work well. My TC is about 1/4" further back than stock. The rest of my drivetrain is stock (except cromoly rear axle shafts) and I haven't grenaded anything, but only street / daily driving so far. Recommend aftermarket driveshafts eventually (I need a new front - torn rzeppa boot - and will probably get a set made local in the next few weeks).

Get your harness and PCM straight from Hotwire Auto. One thing I'm just now experiencing is that the older NGC4 pcms don't have all of the engine control features that come on the current stock SRTs (which are GPEC-2 I think). Shouldn't be surprised, I guess, but just not sure if I'll ever reach the fuel efficiency of the newer SRT cars with the old computer. We'll see. You will also want to get a professional tuning package (HP tuners is what most of the cool kids are using today) and get it to a dyno when you've sorted out all the teething issues. I've put together a tune (using HPT) that seems to be working well now and can send to you, to help you set up your own "baseline" without too much objection from the jeep. I will get mine to a dyno for a fully custom tune but so far I'm all the way up to 13mpg lol.

Get a C&R radiator, and a 2012+ JK "pentastar" fan. I'm using Amsoil heavy duty engine coolant with no problems. Coolant voltage to ground stays right around 0.1V so electrolytic corrosion of the radiator doesn't appear to be a problem at all.

Last item (for now): cruise control probably won't work because the cars use the CAN C bus to send cruise control commands to the pcm; stock Jeep JK uses direct wiring to the pcm. I'm working on a Franken-fix for this and will let you know if it works.

Good luck! Let us know how it goes.

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Discussion Starter #14
A lot of great information, thank you. One other question regarding the transmission. I managed to find a new 238 but the shifter is in the forward position, I noticed yours is in the rear location, did you have to move yours? if so how is this done?
 

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A lot of great information, thank you. One other question regarding the transmission. I managed to find a new 238 but the shifter is in the forward position, I noticed yours is in the rear location, did you have to move yours? if so how is this done?
Great question for sure. I don't know, but I do know that JSS did the front-to-rear shift tower swap on at least one G238. I believe they said they had to replace the shift rail; no idea on other parts. Wouldn't hurt to ask them, but in the mean-time here's the G238 Service Manual. I'd also recommend surfing through the factorychryslerparts website for specific part numbers.
 

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Discussion Starter #16
Sure enough there are two different shift rails for the 238 One for the Ram (forward position) and one for the Dakota (rear position) luckily the parts are available from Mopar. The rear case needs to be removed and some special tools are required but not too bad of a job to change.

On to the next issue, I ordered the motor and trans mounts from JSS and he recommended changing the accessory drive to a 5.7 style from a 2012 Grand Cherokee otherwise there won't be enough room in front for the fan. My 6.4 drive measures 5-5/8" from the rear of the timing cover to the front of the pulleys, does anyone know what the 5.7 setup measures? Just from looking at the pictures it doesn't look much different.
 

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You can see what I had to do to make the 5.7 vvt truck timing cover fit with the JSS weld-in mounts in the intended positions. I think the truck cover is the thickest of the bunch.

https://www.jkowners.com/forum/showthread.php?p=4442272

Recommend doing a test fit. I suspect that you could move the JSS weld-in brackets back about an inch (and possibly massage the tub around the #1 cylinder head / valve cover), which should get you the room up front for the fan. The shift tower might also fit better in the tunnel hole if you move the engine back 1", but it will probably sit about an inch taller than the stock tower either way. My setup has a 1.25" body lift which basically moves the hole up and forward, and makes the tower fitment close to stock. See this:
https://www.jkowners.com/forum/showthread.php?p=4442246

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