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Buying JTR - Spend the $ on a diesel or to regear a 3.6 for 37's?

Sekgunnut

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Nope, that’s on me. I thought 4.10’s were std on all Rubicon’s, but clearly missed the fine print on that one.
Basically you would pay the diesel up charge and regear. I would lean towards the gas motor. Lot of extra coin for something only rarely needed. If stock gears would work then it’s a lot more feasible in my opinion.
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CerOf

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I can’t tell any difference stock gearing with 35s.

that would translate to me feeling a difference with 37s. Enough to make me want to re-gear? Doubtful.

but I did run 35s on my ‘09 jku rubicon and considered it “enough”. So what I’ve got now? Is amazing!
 

Jonny A

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I can't believe you are speaking from experience regarding a JL or JT diesel. I have yet to even detect a hint of a diesel smell on my JT. The joke is what comes out of a new diesel with a DPF in LA is cleaner than what the engine is taking in.

I've yet to experience gelling in the 19 years I've been filling my diesel vehicles, but I understand that if I buy diesel in the summer, it might have a gelling issue if I let that fuel sit until winter.

If gelling was really a problem, how is it that all the trucks that transport products all over the US and Canada seem to run just fine all winter? FYI, the fuel is seasonally adjusted to account for the colder temperatures. As long as you are regularly purchasing diesel fuel, you won't have a gelling problem.
A few days of sub 10 F temps our winter blend diesel gels. We add diesel 911. Runs well then. But it is a step I don't care to be bothered with. And needing to add DEF. Diesels not liking to run for short jaunts? For me a diesel engine is just inconvenient.
 
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Dainbramaged

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I appreciate all the feedback. Pulling the trigger on the JTR with the 3.6l with the Select-trac full time 4WD that is not available on the diesel. Love the idea of all that low RPM torque on the diesel, but just too many little factors that push me to stick with the gas engine. Will have the dealer do the 4.88 regear if that protects the warranty. I'm sure that either would have worked well, just different trade offs.

Now, about the lift.....

Jk, plenty of threads available on that topic
 

smlobx

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^^^

Good choice given your situation.
 

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HooliganActual

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We're selling our Overland and starting over on a JTR. Are we better off spending our available budget on a diesel or a 3.6 8speed that we regear to 4.88's to handle 37’s on both moderately challenging rock crawling and for towing a small camper (not at the same time if things go right)? It will be a daily driver, but low miles.
I know that what I am about to say will spark a new debate so my apologies if your thread gets hijacked. We'll start with the fact that I know nothing about diesels...period. I do however have a JKUR regeared to 4.56 riding on 35's and a JTR with the stock 4.10 gears on 37's and my JTR is much more responsive than the JKR.

Now that might not be much of a comparison, but what I will tell you is that my JTR is build as an overlander. I have so much weight in the rear that I had to have custom rear springs made to handle 900-1200# to prevent the rear end sagging. I estimate I have at least 1000# in the back when you factor in my RTT, ALuCab canopy, Cargo Glide, Kitchen 6 gallons of water, recovery gear, and every bit of camping gear you can imagine. I know this isn't the same as towing a small camping trailer as you have indicated but it's similar.

Since your option was buy a diesel or regear a 3.6 for 37's, I'd say buy whichever one you want but make sure it has the 4.10's. Then, put the 37's on, hook up your trailer and go camping once. Decide whether you really need to regear. When I put 35's on my JKUR which had 3.73 gears, it was a very noticeable difference after regearing to 4.56. HOWEVER, based on my expereince with the JTR now, if I had had 4.10's on my JKUR I might not have regeared.

Buy the one you really want, and then worry about the regear. You may find you don't need it.
 
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stickshifter

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Try talking to another dealer, because that answer is bunk and opposite of what my dealer said. There are so many jeep dealers selling regeared jeeps, and i think they have mopar options for regaring anyway dont they? I think they would have a difficult leg to stand on voiding the entirety of your powertrain warranty for gears if you use dana spicer; since they made the axles. They couldnt say they wont cover cyl misfire or a trans issue on account of gears. If you used non factory gears installed by someone else, then yeah they wont cover a gear or likely a related axle issue; but they cant declare your powertrain warranty void because you regeared, especially with a factory or oem type part.

If you change all the parameters and tq output of a diesel engine, then they can use those reasons to deny all sorts of powertrain claims.
The dealership I talked to was Berthod Motors in Glenwood Springs, CO. It is quite possible that they were wrong; maybe they got bad info from whomever they checked with. However, I believe with absolute certainty that they believed that the info they were providing was true. They knew that it was the opposite of what I wanted to hear, so they had absolutely no incentive for misleading me.

Bottom line: it doesn't matter what I - or anyone else - on the internet tells you about whether or not something affects your warranty. That won't help you when you are standing in the service department looking at a big bill. If you want to mod your Jeep, and you expect that it will not void your warranty, it makes sense to get written confirmation that your mods will not void your warranty from an actual Jeep dealer.
 
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TTEChris

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I've got the JTRD. It's still stock. I have had it in 4L, and that 4:1 transfer case is something else. You have 70% more torque with the diesel over the gas, and that torque is delivered at low RPM.

I've just had mine in snow / ice so far. If it started off in first, it shifted to second so fast, by the time I looked at the console, I saw a D2, and it was switching gears so fast as I was accelerating in the snow.

@TTEChris has been modifying his JTRD on this thread You’re my boy Blue (Diesel JT Build). He had 37's on the JTRD. You could PM him and ask him what he thinks of that combination in reference to what you are looking for. He is planning on replacing his axles, but I don't know what gears he will have then. He said he was getting 24 MPG on his 37's with the 3.73 gears. Then he removed the muffler and his MPG jumped to 28 with 75% of that highway.
My Jeep has come back down to reality since I first installed the 37s. I’m still averaging 22-23mpg with a very heavy wheel/tire combo, but I can’t get anywhere near the 28mpg I managed that first trip home. Some of it could be the throttle booster I installed, or just me not really trying anymore since the Jeep is now more fun to drive.
We just finished a JLU Diesel with 40s and D60’s(4.88 gears.) He is keeping the front hubs locked during break in and is still managing a bit above 20mpg. His 40” tires and Beadlocks only weigh 1 pound more than my wheel/tire combo but I would have guessed with the lack of a FAD and the front hubs engaged he would be averaging a lot less. My old 3.6 JT on 41s would be lucky to get 12mpg with the hubs locked.
 

syreeves

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I'd do the diesel. Problem solved from the factory so no warranty issues. Mileage is better and low range torque is better for crawling and towing.
Uh - quoting my own post - thats probably some kind of no-no. Anyway - I forgot to mention that I assume you are getting the 8sp auto? I wanted the 6MT so diesel was not an option :(. If I could have gotten the 6MT with the diesel I would have been happy to survive on ramen and PBJ for a couple of years... with my luck that combination will be offered with Mojito or Punkn again next year... and I'll just have to live with my slow and boring silver 6MT. [I know- first world problems...]
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