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2014 Grand Cherokee Summit 4x4
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Discussion Starter · #1 ·
I have a 2014 GC Summit 4x4, I love the car but have never been happy with the amount of power it has with the 3.6, and have been looking into options for tuning and such. Fast forward to last week, the head gasket has decided to let go, which I am going to attribute to the stop leak that seems to have been added to the system by the previous owner.

I am looking at either replacing the 3.6l, or what I would like to find out, possibly swapping in a 5.7 or 6.4. From what I have read the 3.6 and 5.7 transmissions are all the same since they switched to the 8 speed*, so the engine might bolt right up. But I have no idea about the feasibility of doing this, I have found a couple of used engines, with ecu and harness included, and they aren't a whole lot more that the 3.6. If the engine is pulled from another grand cherokee, how much else differs between the two powertrains, and is it worth doing.


(*although that is from my understanding, I could not find it specifically stated)
 

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2014 Summit 5.7
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First issue is the trans are not the same. In 2014 the 3.6 uses the 8-spd 845RE and the 5.7 and 6.4 use the 8-spd 8HP70. The 8HP70 handles more power so even if it fit probably not a good idea to put a 5.7 let alone a 6.4 on an 845RE.
 

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Discussion Starter · #3 ·
That is good to know, I was not aware of that. If I were to acquire engine, trans and harness/ecu from a wrecked vehicle, how much else is there that could potentially cause issues, and is it worth it? (Replacing the vehicle is not at option at the current moment due to other external factors)
 

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2014 Summit 5.7
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hmm well off top of my head I think radiator different 3.6 has a lower cooling capacity than 5.7.. I think gears are different in rear between the two. probably going to be a lot of rabbit holes to run down with a change like that. I haven't pulled an engine on this jeep so I dont know exactly everything maybe someone will respond who can tell you the deeper detail but I think if cost is an issue things will probably add up quickly. Good luck
 

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Whole lots of differences - larger brakes, cooling capacity, more robust 8 speed, dual tailpipes, different rear end ratios which the ecu will notice, etc., - possible if you throw enough money into it, but I would trade or find another with the V8.
 

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Try using K seal head gasket repair fluid. It was recommended to me by a high end mechanic, I put it in my 06 to stop a heater core leak and that has lasted 40k miles. It uses ceramic fibers that coagulate at the repair point, so unique compared to other stop leak items. A head gasket will not go bad by adding stop leak, the prior owner sold it after realizing the head gasket went.
 

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I have a 2014 GC Summit 4x4, I love the car but have never been happy with the amount of power it has with the 3.6, and have been looking into options for tuning and such. Fast forward to last week, the head gasket has decided to let go, which I am going to attribute to the stop leak that seems to have been added to the system by the previous owner.

I am looking at either replacing the 3.6l, or what I would like to find out, possibly swapping in a 5.7 or 6.4. From what I have read the 3.6 and 5.7 transmissions are all the same since they switched to the 8 speed*, so the engine might bolt right up. But I have no idea about the feasibility of doing this, I have found a couple of used engines, with ecu and harness included, and they aren't a whole lot more that the 3.6. If the engine is pulled from another grand cherokee, how much else differs between the two powertrains, and is it worth doing.


(*although that is from my understanding, I could not find it specifically stated)
Take the money you would spend trying and just upgrade to a GC that has a V8. (your current transmission could theoretically handle the torque and HP of the V8 but there are other factors to consider). There's no way to do a successful swap like that without spending waaaay more $$$ than you would on just trading it in.
 
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