Anyone with a higher-mileage JK?

ut_prosim

Member
Joined
Nov 19, 2015
Location
Hillsborough, NC
I'm checking out a '12 JKUR near Clemson this weekend, seems to check all the boxes for what I'm looking for, but I keep hearing horror stories about the reliability of the NSG370 6spd transmission, as well as just overall reliability.

Is there anyone here who's put some miles on their JK, and what have you had to do to get it there? The one I'm interested in has 66K on the clock already, and I'd like to get 250,000 out of it.
 
I love jeeps, but I have never know any Chrysler product to be the model of reliability. Before it's said, I know the 4.0 was a great motor back in the day.
 
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Check the build date on the motor. Early ones made in fall of 2011 had some issues. But the 3.6 is a fantastic little engine.

Also, I think this exact question has been asked/answered on the JKOWNERS forum.

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Mine just rolled 60k ( not an easy life either). It has made many trips to uwharrie, the mountains, the flats, and the beach on 33's its whole life. So far... so good.... lol. I work at a jeep dealership, and hardly ever see these come in with any major drivetrain issues (other than cylinder heads). Also still on my original clutch. Now I did see one come in with 12k on the clock because someone snatched second gear a little too hard lol.
 
I just hit 78k miles today, only quirk I've had is sometimes going into reverse is gimmicky. Gotta let the clutch out then push it back it for it to go in. Mine is a 6sp and I do drive if somewhat hard,
 
The 3.8 in the older Jks is shit, the 3.6 seems to be ok, LS would be sweet! Now if someone would just chime in on the transmission and actually answer the OP!:D
 
Just did and my 3.8 has been pretty reliable but I do keep it maintained well.
 
NC_IslandRunner said:
The 3.8 in the older Jks is shit, the 3.6 seems to be ok, LS would be sweet! Now if someone would just chime in on the transmission and actually answer the OP!:D
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When I was at the Jeep dealer (14 years) I was the drivetrain tech. Lots of automatic trans repairs, tons of axle repairs and more clutches than I can remember.
About the only thing I ever did to the 370s was a few clutches and a couple service kits to repair the popping out of reverse.
I never had a single catastrophic failure or one that required "hard part" repairs.
My advice is to make sure the axles are geared appropriately for the tire size to alleviate strain on the clutch and trans. Keep good fluid in it and let it eat.
 
We're those the German 5 spd autos or the older 42re 4 spds?

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My wife's uncle had a high mileage JK (~140,000). Manual transmission did slip some, it needed a new clutch, and the rear main seal leaked a lot. He was rough on it. I think it had the 3.8 motor with Dynatrac 60's, 5.13 gears, 38" tires, heavy beadlock wheels, and more armor than you could shake a stick at.
 
NC_IslandRunner said:
No level of maintenance makes it stronger. Weak minivan engine. Struggles to pull 1000lb trailer my Impala pulls without issue.
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Gearing is key, and from my experience the 3.8 has better low end grunt when crawling then the 3.6. But I'm use to driving big shit that's slow, as long as 4 low works and it can somewhat maintain highway speeds with cruise control in a giant brick then what more could you ask? On 37x12.50 SSRs I averaged 16.5 mpg hand calculated while driving from Cali to NC with stock 4.10s. Never put it in 6th but it ran the cruise and was blowing all over the road.

Also while wheeling rocks out west, I stalled less than another buddy on 37s with 4.88s, he later switched to 5.38s, on his '15 4 door rubi with a 6spd. Maybe I'm just Ricky Bobby with my clutch foot or the 3.8 actually has better low end torque.

And for the record on 38.5x14.50 TSL/SX on steel wheels, stock 4.10s, I have had it chirp going into 3rd and it barks them hard going into 2nd. But remember it's under powered according to everyone who thinks jeeps should be a corvette on 35s.
 
Chris_M said:
I was referring to your post of lots of auto trans repairs.

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My bad. I was referring to the 42RLE. They aren't THAT bad as long as you treat them like the marginally adequate transmission they are. Keep them cool, gear your diff ASAP after adding larger tires and/ or weight.
Every single one I repaired was due to overheating. Generally an overheated 42 would need a pump, converter and valve body. The converter would start slipping and then those clutch fibers would contaminate the valve body and pump.
The same thing applies to the same trans when it was in TJs
The old 32RH autos were essentially bulletproof as long as you didn't try to run muddy water in them.
 
Bogleparsons said:
38's on 4:10's..... I'm glad you like it but fuck that shit.
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Oh it sucks but around town it's not that bad, and with the 4:1 tcase it helps if our a bit. I've just been to busy with school to regear to 5.38s. But that'll change this summer.
 
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