Sponsored
OP
OP
montechie

montechie

Well-Known Member
First Name
Wes
Joined
Nov 26, 2021
Threads
3
Messages
196
Reaction score
371
Location
Bozeman, MT, USA
Vehicle(s)
2005 LJ Rubicon, 2022 JT Rubicon
Occupation
Writer of code, designer of things
Some interesting answers, but nice high-level info. I agree about what he said with the 4.0, both the strengths and weaknesses. It's been pretty simple for me to work on, the '05-06 Rubicons had more electronics in the form of sensors, but not too many. I already preemptively replaced the cooling system at 120K (with OEM) based on others' experience on what breaks on the trail.

Some interesting confirmations on the JT/JL issues that I see on this forum. I was expecting electrical mods to be the #1 warranty rejection, just because of the challenge of properly debugging e-gremlins and the interrelationship of electrical components.
 

jebiruph

Well-Known Member
First Name
Jerry
Joined
Dec 9, 2018
Threads
14
Messages
607
Reaction score
567
Location
IA
Vehicle(s)
2018 Wrangler JL 2019 Cherokee KL 2020 Gladiator JT
Some interesting answers, but nice high-level info. I agree about what he said with the 4.0, both the strengths and weaknesses. It's been pretty simple for me to work on, the '05-06 Rubicons had more electronics in the form of sensors, but not too many. I already preemptively replaced the cooling system at 120K (with OEM) based on others' experience on what breaks on the trail.

Some interesting confirmations on the JT/JL issues that I see on this forum. I was expecting electrical mods to be the #1 warranty rejection, just because of the challenge of properly debugging e-gremlins and the interrelationship of electrical components.
Have you heard of any issues with the 05-06 4.0 OPDA (oil pump drive adapter) failures resulting in catastrophic engine failure? I noticed the Jeep expert also did not address the early TJ 4.0 cylinder head failure due to weak castings that wasn't resolved until 2003.
 
OP
OP
montechie

montechie

Well-Known Member
First Name
Wes
Joined
Nov 26, 2021
Threads
3
Messages
196
Reaction score
371
Location
Bozeman, MT, USA
Vehicle(s)
2005 LJ Rubicon, 2022 JT Rubicon
Occupation
Writer of code, designer of things
Have you heard of any issues with the 05-06 4.0 OPDA (oil pump drive adapter) failures resulting in catastrophic engine failure? I noticed the Jeep expert also did not address the early TJ 4.0 cylinder head failure due to weak castings that wasn't resolved until 2003.
I actually haven't come across the OPDA issue. I had a transmission pump failure at around 120K and 17 years, and some sensor failures around the same time (cam, map) that I believe are specific to the Rubicon 4.0s of the time.
 

Lunentucker

Well-Known Member
Joined
Apr 24, 2022
Threads
154
Messages
3,898
Reaction score
9,495
Location
Virginia
Vehicle(s)
2021 Jeep Gladiator Mojave
Occupation
People Work?
He said the same thing about cold air intakes that I had already deduced on my own. The PCM controls the air/fuel mix and the factory filter setup gives it more air than it can use.
Unless you can change the tuning you're not getting anything but a different sound.

 
Last edited:

Sponsored

BearFootSam

Well-Known Member
First Name
Jim
Joined
Oct 12, 2022
Threads
6
Messages
410
Reaction score
607
Location
PNW
Vehicle(s)
22' Gladiator Rubicon
Occupation
Fed
There are two main factors in reliability, the inherent design/manufacture and maintenance. We've had s lot of high mileage vehicles in my family, Honda, Jeep, VW, Toyota, and the common thread is that they were all purchased new and well cared for. Scheduled maintenance by the book and hitting wear items and issues promptly are key. The jeep is nice for being relatively easy to work on, plenty of space, robust design.
 

ShadowsPapa

Well-Known Member
First Name
Bill
Joined
Oct 12, 2019
Threads
163
Messages
26,780
Reaction score
31,244
Location
Runnells, Iowa
Vehicle(s)
'22 JTO, '23 JLU, '82 SX4, '73 P. Cardin Javelin
Occupation
Retired auto mechanic, frmr gov't ntwrk security admin
Vehicle Showcase
3
and the factory filter setup gives it more air than it can use.
That's a "duh".
Anyone who has calculated cams (lifts, durations, scavenging), displacements and CFM requirements would know and yet others will say "but this guy on youtube proves it works" or similar bunk.
Only if other things are changed, and the tune is changed and you race it at high RPM.
The engine is a pump. You can figure tha air needs pretty easily. And the 3.6 is not a big pump.
Cubic Feet per Minute (of air pumped by the engine). The air filter and housing, etc. can handle all this engine can use.
I suppose one could put a sensitive vacuum gauge in the air intake between throttle body and filter media to prove it.
 

Klutch

Well-Known Member
Joined
May 25, 2019
Threads
18
Messages
816
Reaction score
1,005
Location
Colorado Springs
Vehicle(s)
1986 Jeep Comanche, 2000 Jeep Cherokee
Him saying 385,000 miles on a Jeep in about a year was a head scratcher.
I wondered about that. I suppose someone who drives his Jeep constantly to Alaska, The Yukon, Southern Mexico and back could put that many miles on a Jeep in a year.

I'm reminded of a Navy buddy I met in a tech school in Key West. He had driven there from his home town near Seattle. He drove a 1971 Dodge Demon with a Slant Six. That's one serious road trip!
 

Lunentucker

Well-Known Member
Joined
Apr 24, 2022
Threads
154
Messages
3,898
Reaction score
9,495
Location
Virginia
Vehicle(s)
2021 Jeep Gladiator Mojave
Occupation
People Work?
I wondered about that. I suppose someone who drives his Jeep constantly to Alaska, The Yukon, Southern Mexico and back could put that many miles on a Jeep in a year.

I'm reminded of a Navy buddy I met in a tech school in Key West. He had driven there from his home town near Seattle. He drove a 1971 Dodge Demon with a Slant Six. That's one serious road trip!
It's about 44 mph 24/7/365
 

Sponsored

ShadowsPapa

Well-Known Member
First Name
Bill
Joined
Oct 12, 2019
Threads
163
Messages
26,780
Reaction score
31,244
Location
Runnells, Iowa
Vehicle(s)
'22 JTO, '23 JLU, '82 SX4, '73 P. Cardin Javelin
Occupation
Retired auto mechanic, frmr gov't ntwrk security admin
Vehicle Showcase
3
It's about 44 mph 24/7/365
There's that danged math, and logic, again.
You forgot about eating and potty time and sleeping in a RTT now and then.
 
OP
OP
montechie

montechie

Well-Known Member
First Name
Wes
Joined
Nov 26, 2021
Threads
3
Messages
196
Reaction score
371
Location
Bozeman, MT, USA
Vehicle(s)
2005 LJ Rubicon, 2022 JT Rubicon
Occupation
Writer of code, designer of things
40s on a Dana 44?
I wish that speed question had a followup. With axle shaft, u-joint upgrades and trussing maybe? People compete on those setups, but usually with way lighter rigs. At some point after all the work on a 44 you may as well have spent the $ on a 60 or similar. Not sure if you are doing your own work though.

Or keeping it as a mall crawler and passing the damage to the next owner...
 

Tuggernuts

Well-Known Member
First Name
Scott
Joined
Oct 29, 2020
Threads
7
Messages
540
Reaction score
910
Location
NorCal
Vehicle(s)
Ram 1500
Occupation
Truck driver
I wish that speed question had a followup. With axle shaft, u-joint upgrades and trussing maybe? People compete on those setups, but usually with way lighter rigs. At some point after all the work on a 44 you may as well have spent the $ on a 60 or similar. Not sure if you are doing your own work though.

Or keeping it as a mall crawler and passing the damage to the next owner...
There is no way I’d put 40s on a Dana 44, trussed or not.
 
 



Top