JPop

I don't have any issues with my Hemi Dodge Ram, with plenty of power, but the 545RFE leaves a lot to be desired.

Zaskar

Cummins 4BT!!

http://www.youtube.com/watch?v=hdWNaUvxtTs

REDJEEPJK

When I was in Florida for jazz school In oct to dec last year they had a jeep T a jeep shop that had a 4bt and it was awesome I'd love to do this swap so badly but I really think the supercharger is in my opinion a better way to go but I hAve looked for used 4bt motors and I have found some in tx and I was considering it but itd be a lot in labor I have looked in forums and went to the Jeeptober fest in fl and it was the most fun best jeep get together I have ever been to!! I saw a jeep CJ with a 4bt it was awesome!!! Awesome video by the way!

aldaman

Although my '08 JK still had the 3.8L engine, even with the 5.13 gearing, my auto trans had the same feeling/symptom as you described. At times it would seem like it was lagging and then when I get on the gas, the rpm would skyrocket. The engine was okay, but mated with the auto trans it was horrible. I wonder if I had a manual trans if things would have been different Now I am just waiting for my '12 JKU Rubi to be built and delivered....

I did see the LS-3 swap on a JKU on you tube. I really like how the Jeep would be on cruise control and would hold it's speed/rpm on any incline without the trans having to downshift to maintain its speed. Maybe the question is not about the type of engine (hemi vs Chevy) but rather just trying to get the right auto trans to match the engine and not worry about the gear searching....

OscarTheJeep

I think the 3.8 gets a bad rep because the four speed auto behind it sucks! I'd be content with a 45RFE behind my 3.8 like my Liberty had behind the 3.7. I wish a company would get off their ass and work on a transmission swap. I think it would be more economical for the masses and be easier to complete for the average Joe.

Dblaron

Ill be first in line as well. The motor ya maybe its not oozing power but then again i had a tj and everyone whined about the 4.0. If i could wheel it all day long without hot oil coming on or having to downshift because of it crap gearing I'm in. Im mot worried about racing civics anyway just getting strong performance and a little bit of towing without fear my trans is gonna shoot out my exhaust ( hypothetical)


Lets go venders.

chuck45

I've followed some diesels on slow trails in Moab. I hate the stench and the noise. I stay as far in front of them as I can and sure don't want to be in one. Over the road is another matter.

chuck45

it completely transforms the JK. There is no comparison to stock and it feels much better than the Hemi's I've driven and ridden in. The only, and I mean ONLY, good thing about the Hemi is that Chrysler hung a cool name on it. Other than that is is just an old school cast iron clunker of an engine. There is no comparison between a Hemi and a Gen 3 or Gen 4 5.3 or 6.2 engine. And the huge bonus is that you get the 6L80 transmission with it; which is the secret weapon in the 5.3 or 6.3 LS swap.

I drove a 6.2/6L80 4 door Wrangler that was just about as heavy as mine. This Jeep had the 2.72 TC. Going down a hill, in 2Hi in 1st gear (the paddle shifter for the 6L80 is awesome) it went slower than my Rubi in 1st gear and 4Low. Yes I said 4 LOW! I have 37's and 5.13's and the 6.2 equipped Jeep had 35's and 4.10's.

We later were climbing a grade at 50 MPH that would have had my JK in second gear and 4000 rpm. The 6.2 6L80 was was in Cruise Control, maintaing speed to within 1 MPH, in 6th gear at 1100 RPM, and felt great.

At this point in time their is no longer any excuse for putting a Hemi in a JK.

Their is one further advantage to going with an LS. When your Jeep TIPM dies and you need a tow to the dealer to get it reflashed or replaced, the LS electronics are completely separate and the engine and trans function normally. This happens because they add a relay that runs the fuel pump if the Jeeps electronics die. And frankly the Jeep electronics are lousy and I hate 2000 tows from remote places.

aftahour

would love to do diesel 4bt but in cali cant happen as DD. but hemi or ls is only option. sigh

chuck45

have MoTech do it. I have been so busy at work I've only been home about four days a month since May. If I take vacation for two or three weeks to do the conversion the lost income (salary only and loosing my job bonuses) equals the cost they want do do the labor of the conversion.

So the wife and I put the 6.2/6L80 in the pickup bed, the JK on a trailer (it is burning so much oil we didn't think the rings would make the 500 mile drive down) and took it from Grand Junction to Las Vegas and dropped it off with Robbie and his crew.

So now it is a matter of waiting and writing a check. We're hoping to have it back in time to do Holidays in Moab with Bill Burke (and hoping for a bunch of snow this year). Doing behind the Rocks in two foot of snow is a blast!

I'll post pics and a performance review when i get it back. Once I see what RPM it runs down the freeway at I'll most likely regear. I'm sure the 5.13's will be a bit much and am thinking of going to 4.56's. If I do I may drop the dollars on a Dana 60 in the rear. I just had the front axle reinforced with an external sleeve, 1/4" bracketry, C gussets and a truss and will stay with that for a while. I also had the knuckles rolled to a 12 degree separation instead of the stock 6 degree so now I can have the proper caster and pinion angle.

Chuck