Jeep Technician (And Gladiator Owner) Discusses Common Questions and Problems on TrailRecon

[lo-fi]

1. Don't modify your 3.6L engine- First mod I would do is a catch can.
2. Death Wobble: Steering Stabilizer should be changed if lifted. Avoid cheap shocks. Dumbest thing I have ever heard- steering stabilizers mask the starting signs of many issues that cause death wobble. Without going too far in the weeds- PSC Big Bore with a ram assist would be the only “damper” I would recommend, as it’s not a damper but does remove the stress from the steering box and frame deflection and is ultimately what’s needed for 37+ tires and wheeling…
3. Is Toyota more reliable? No. Toyota was awesome until the 2012 soy-based wiring idea, then too many other issues get added after this time frame.
4. What is the most reliable engine? 4.0, 3.8, and 3.6 in that order. 4.0 was probably the most consistent motor of the last 20 years for Jeep. 3.8 is trash, NEW 2018+ 3.6 is sketchy, 2014-2017 3.6 was fine (rocker issues). 3.0 is a roll of the dice- purely emissions and fuel pump being the concerns
5. What mod causes the most warranty issues? Lifts I understand that we are talking about $50-70k toys… but if you are taking them to go play and have a good time- go have a good time, warranty? Some times you have to pay to play… if your not willing to pay up then this probably isn’t for you.. trail fixes, abuse etc. things are going to break. Quite frankly I’m blown away at how much trust a lot of folks on this forum have in their dealer techs to fix things… I struggle to trust an oil change, as the 3 “free” had oil spilled everywhere, cringing over when mine goes in for the fuel pump and upper oil pan gasket.
6. Doesn't recommend forced induction on the 3.6L. Doesn't feel the bang for the buck is there plus potential issues.
Forced induction is a good time! But seriously? If your going down this road, a bolt on is a starting point… internals need to be done. The JL/Jt 3.6 is a high compression motor engineers pushed for efficiency and refinement- turbos and superchargers are going to require more in-depth work- period.
7. Most reliable Jeep? 2003 to 2006 4.0L
Manual LJR would probably be my top pick.
8. Why does the Jeep Wrangler 3.6L Oil Cooler Fail? Made of plastic, it sucks.Agree
9. Regearing is crucial after lift and tires. Also agree- the transmission gears debate is comical. Sure down shifting works but re-gear all day long is the resolution to bringing back the required tq to turn bigger tires…
10. Least reliable engine? 2011-2014.5 3.6L I would argue the 2018+ 3.6 and it’s higher compression bring more issues to the table than the rocker issues of the 2012-2017.
11. Auxillary Battery is a frequent sore spot.
My opinion- the way the auxiliary battery is tied into the system is frustrating. I understand it’s use/functionality, it just seems to me that it is a parasite within the electrical system. I say this but it isn’t a high enough concern- I have not ripped mine out yet- will cross that bridge sometime in the next 12 months.

Thanks for sharing. I do all my own work and haven't owned an unmodified vehicle since 2016 plus I'm currently playing catch up on these vehicles. With that said, all of my vehicles were/are sports cars. W204 C63 AMG, Focus ST, E46 M3, and a Mach 1 Mustang. I'm new to the modern truck scene and trying to capture all the advice I can before starting out on any type of modifications. I've learned to be patient the hard way.

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[ShadowsPapa]

1. Don't modify your 3.6L engine
2. Death Wobble: Steering Stabilizer should be changed if lifted. Avoid cheap shocks.
3. Is Toyota more reliable? No
4. What is the most reliable engine? 4.0, 3.8, and 3.6 in that order.
5. What mod causes the most warranty issues? Lifts
6. Doesn't recommend forced induction on the 3.6L. Doesn't feel the bang for the buck is there plus potential issues.
7. Most reliable Jeep? 2003 to 2006 4.0L
8. Why does the Jeep Wrangler 3.6L Oil Cooler Fail? Made of plastic, it sucks.
9. Regearing is crucial after lift and tires.
10. Least reliable engine? 2011-2014.5 3.6L
11. Auxillary Battery is a frequent sore spot.

LOL

As far as 11 - mostly because of the crap "information" and MIS-information out there, lack of understanding and so on.

9 - why is it crucial? that's a bad blanket statement. For some tire jumps it makes no sense. And what's a lift got to do with gearing?
Define "tires". Some go to 34s and 35s and have little trouble. With an automatic, the TC pretty well masks the loss of low end. It's a debate with no end, depends on how it's USED, the size of tires, weight of the jeep and more.

My guess on the "reliability" bit is he's not looking at percentages but raw numbers.
Percentage-wise, I can't see the 3.6 being unreliable. Granted, the 4.0 is a killer work-horse, extremely reliable, but one also has to look at how hard an engine is being worked.
Long stroke, low RPM, low compression engines of course will last a long time compared to high RPM, short stroke high compression engines. That's just a given.
But I'd like to see percentages (and did he consider leaks in his thoughts?)
#7 - most "reliable" jeep - WJ with 4.0 - to a point. They had a ton of troubles with the ABS and the wiring between body and door - wires flexed and broke, rear wiper troubles, rust. (But still my favorite of all Grand Cherokees)

But #2 did it for me. So many "experts" out there jump to youtube, get their clicks and fame and talk like they know and everyone loves it and eats it up and yet........... REAL experts, those who design, are engineers and have raced and rallied Jeeps for years would disagree with him. He's just a tech, not an expert. I've posted quotes and images many times here how the stabilizer is a mask, and isn't intended to resolve "DW". It's for bump steer more than anything.

 

[lo-fi]

LOL

As far as 11 - mostly because of the crap "information" and MIS-information out there, lack of understanding and so on.

9 - why is it crucial? that's a bad blanket statement. For some tire jumps it makes no sense. And what's a lift got to do with gearing?
Define "tires". Some go to 34s and 35s and have little trouble. With an automatic, the TC pretty well masks the loss of low end. It's a debate with no end, depends on how it's USED, the size of tires, weight of the jeep and more.

My guess on the "reliability" bit is he's not looking at percentages but raw numbers.
Percentage-wise, I can't see the 3.6 being unreliable. Granted, the 4.0 is a killer work-horse, extremely reliable, but one also has to look at how hard an engine is being worked.
Long stroke, low RPM, low compression engines of course will last a long time compared to high RPM, short stroke high compression engines. That's just a given.
But I'd like to see percentages (and did he consider leaks in his thoughts?)
#7 - most "reliable" jeep - WJ with 4.0 - to a point. They had a ton of troubles with the ABS and the wiring between body and door - wires flexed and broke, rear wiper troubles, rust. (But still my favorite of all Grand Cherokees)

But #2 did it for me. So many "experts" out there jump to youtube, get their clicks and fame and talk like they know and everyone loves it and eats it up and yet........... REAL experts, those who design, are engineers and have raced and rallied Jeeps for years would disagree with him. He's just a tech, not an expert. I've posted quotes and images many times here how the stabilizer is a mask, and isn't intended to resolve "DW". It's for bump steer more than anything.

Thanks for sharing the knowledge. I've got a lot to learn about these trucks.

 

[DaveL]

According to this one technician, zero engine modifications including intakes. Again, he doesn't feel the cost justifies the gains because the gains are little to non-existent.

15 minutes and 4 seconds he discusses air filters/intake.

Welcome to the forum! I used to buy oiled filters and use them. Thanks for your note.

 

[DaveL]

LOL

As far as 11 - mostly because of the crap "information" and MIS-information out there, lack of understanding and so on.

9 - why is it crucial? that's a bad blanket statement. For some tire jumps it makes no sense. And what's a lift got to do with gearing?
Define "tires". Some go to 34s and 35s and have little trouble. With an automatic, the TC pretty well masks the loss of low end. It's a debate with no end, depends on how it's USED, the size of tires, weight of the jeep and more.

My guess on the "reliability" bit is he's not looking at percentages but raw numbers.
Percentage-wise, I can't see the 3.6 being unreliable. Granted, the 4.0 is a killer work-horse, extremely reliable, but one also has to look at how hard an engine is being worked.
Long stroke, low RPM, low compression engines of course will last a long time compared to high RPM, short stroke high compression engines. That's just a given.
But I'd like to see percentages (and did he consider leaks in his thoughts?)
#7 - most "reliable" jeep - WJ with 4.0 - to a point. They had a ton of troubles with the ABS and the wiring between body and door - wires flexed and broke, rear wiper troubles, rust. (But still my favorite of all Grand Cherokees)

But #2 did it for me. So many "experts" out there jump to youtube, get their clicks and fame and talk like they know and everyone loves it and eats it up and yet........... REAL experts, those who design, are engineers and have raced and rallied Jeeps for years would disagree with him. He's just a tech, not an expert. I've posted quotes and images many times here how the stabilizer is a mask, and isn't intended to resolve "DW". It's for bump steer more than anything.

Our 2019 had terminal wander.

Took the JLU in and the dealer did a wall job. Parked it next to the wall and ignored it. They did assure me that all TSB's had been done. Said it was the same as a new vehicle they had. Said It was A Jeep Thing. Surprised that's not on the option list. Jeep Thing.

 

[Pescatoral Pursuit]

Surprised that's not on the option list. Jeep Thing.

It comes standard.

 

[ShadowsPapa]

Our 2019 had terminal wander.

Took the JLU in and the dealer did a wall job. Parked it next to the wall and ignored it. They did assure me that all TSB's had been done. Said it was the same as a new vehicle they had. Said It was A Jeep Thing. Surprised that's not on the option list. Jeep Thing.

When I took my 2020 in for the original steering gear TSB, the service advisor AND the technician both said "these shouldn't do that" and were surprised at it. The service advisor even said "I've driven other Gladiator and Wranglers on the lot and they don't act this way" and they didn't even think twice - it went in and got fixed.
Then after a few months the issues returned - and they said "yeah, it's got a problem, we'll have to replace the steering gear". That was that. Fixed without issue.
When I ordered my 2022, I made sure the "Jeep thing" box wasn't checked.

 

[Jteakus]

I took my 2020 JL in for the steering box upgrade. I was denied because of aftermarket wheels and tires. It has 315 BFG AT's on Mopar beadlock wheels. I told the service writer, "You realize those are the exact same tires and wheels that are on the XR parked on your showroom floor right?" Crickets.
Lost a customer forever. I kinda liked that dealer too.

 

[Lost1wing]

When I took my 2020 in for the original steering gear TSB, the service advisor AND the technician both said "these shouldn't do that" and were surprised at it. The service advisor even said "I've driven other Gladiator and Wranglers on the lot and they don't act this way" and they didn't even think twice - it went in and got fixed.
Then after a few months the issues returned - and they said "yeah, it's got a problem, we'll have to replace the steering gear". That was that. Fixed without issue.
When I ordered my 2022, I made sure the "Jeep thing" box wasn't checked.

Same here, 2020 JTR steering gear replaced on the first visit. Problem solved.

 

[DaveL]

When I took my 2020 in for the original steering gear TSB, the service advisor AND the technician both said "these shouldn't do that" and were surprised at it. The service advisor even said "I've driven other Gladiator and Wranglers on the lot and they don't act this way" and they didn't even think twice - it went in and got fixed.
Then after a few months the issues returned - and they said "yeah, it's got a problem, we'll have to replace the steering gear". That was that. Fixed without issue.
When I ordered my 2022, I made sure the "Jeep thing" box wasn't checked.

Dealer for the 2019 was polite and seemed reasonable. Put a dashcam in and realized that their service was so bad.

 

[TwelveGaugeSage]

Inline-6 motors are just hard to screw up. Off the top of my head, the 4.0, Ford 300, and Chrysler slant-6 were just unkillable motors. BMW, Toyota, and Nissan had some pretty awesome I-6 motors as well. Bonus on the SOHC and DOHC motors is only one head to deal with so they were significantly smaller and much easier to work on versus the V6s. Though on a motorcycle gimmie a nice horizontally opposed engine. The Gold Wing motor on my 78 is sooooo easy to work on.

 

[Wheelin98TJ]

Inline-6 motors are just hard to screw up. Off the top of my head, the 4.0, Ford 300, and Chrysler slant-6 were just unkillable motors. BMW, Toyota, and Nissan had some pretty awesome I-6 motors as well. Bonus on the SOHC and DOHC motors is only one head to deal with so they were significantly smaller and much easier to work on versus the V6s. Though on a motorcycle gimmie a nice horizontally opposed engine. The Gold Wing motor on my 78 is sooooo easy to work on.

There were some issues with the 4.0 I6. Remember the TUPY head?

I had a 4.0 I6 that broke a piston skirt at 160k miles. Not something I'd consider common, but there are some examples of this.

And not really a motor issue, but both the Ford 300 and the Jeep 4.0 had exhaust manifold/header cracking problems.

 

[ShadowsPapa]

There were some issues with the 4.0 I6. Remember the TUPY head?

I had a 4.0 I6 that broke a piston skirt at 160k miles. Not something I'd consider common, but there are some examples of this.

And not really a motor issue, but both the Ford 300 and the Jeep 4.0 had exhaust manifold/header cracking problems.

The 4.0 exhaust header cracking was the collector area - it was more of a header and the different tubes heated and cooled at different rates. The solution? An after-market header, or have a neighbor pull the collector off and totally re-weld it back on. That's what I did - no cracks in 11 years since.
Any I6 is more prone to manifold issues, even head issues, but especially manifolds, due to the length, stresses of heating and cooling. That's why there's often multiple torque specs for the same manifold - tighter in the middle, looser on the ends and large pieces that allow some flexing without things coming loose. The key was to re-torque now and then. Even the owners manual in the early AMC/Ramblers had instructions on how to re-torque the head of their flat head I6 to prevent head cracking, or loosening. It's just an issue with long heads and manifolds. I saw it on almost every I6 that ever came into the shops I worked in. Heck, even the Iron Duke had head issues at times. That was a teeny I4.

The original 0331 was the problem (2000-2002) the TUPY was the solution - still a 0331, but thicker deck.
or
This head although this is one of only three known to exist -

I was curious as to what the chamber size was on this head - matches stock perfectly. (but I had the 4.0 head for my Eagle's engine shaved by 0.024" so it's not really stock CC any more)

 

[Wheelin98TJ]

The 4.0 exhaust header cracking was the collector area - it was more of a header and the different tubes heated and cooled at different rates. The solution? An after-market header, or have a neighbor pull the collector off and totally re-weld it back on. That's what I did - no cracks in 11 years since.
Any I6 is more prone to manifold issues, even head issues, but especially manifolds, due to the length, stresses of heating and cooling. That's why there's often multiple torque specs for the same manifold - tighter in the middle, looser on the ends and large pieces that allow some flexing without things coming loose. The key was to re-torque now and then. Even the owners manual in the early AMC/Ramblers had instructions on how to re-torque the head of their flat head I6 to prevent head cracking, or loosening. It's just an issue with long heads and manifolds. I saw it on almost every I6 that ever came into the shops I worked in. Heck, even the Iron Duke had head issues at times. That was a teeny I4.

The original 0331 was the problem (2000-2002) the TUPY was the solution - still a 0331, but thicker deck.
or
This head although this is one of only three known to exist -

I was curious as to what the chamber size was on this head - matches stock perfectly. (but I had the 4.0 head for my Eagle's engine shaved by 0.024" so it's not really stock CC any more)

You're right, it was the 0331 head and the TUPY was the solution.

I think the best solution for the cracking headers/manifolds was the 2 piece design. So you don't have such a long, single piece header.

 

[AmosMoses]

The 3.8 is more reliable than the 3.6?

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