1) Tranny. Main issues is Govenor pressure solenoid, has numerous other issues with the tranny but the solenoids are the biggest one.
2) Magnum engines come from the factory with cracked heads, crack heads are ruining the world.
3) Plenum pan. Stupid engineers designed this so after 30k they will get your truck into the stealership, do the warranty work and then tax you on the other non warranty repairs.
4) Fuel Pump has a defectively designed check valve, goes bad and lets the fuel drain back into the tank, takes several togglings of the ignition to prime the fuel system to overcome hard start.
5) Brake caliper issues, hanging up and warping rotors, usually do to slides.
6) Paint issues, usually PX8 disease but known to affect every color, clearcoat is FAMOUS for peeling off, sometimes the clearcoat comes off the truck in one piece. LMAO
7) P0140, O2 sensors on dodges suck ***, replace and replace again... Plenum issues cause alot of O2 sensor problems.
8) Intake bolts. Designed with oversize holes so that water pools in them causing excessive corrosion leading to shearing of bolts and more issues.
9) 9-1/4 rearend, blaming DANA for issues and vise-versa. Rearend has several documented issues. Blame game.
10) Gas mileage, need I say more, these pigs are made to run extremely rich from the factory, excessive carbon build up quickly deteriorates any performance these engines had. Rich running engines make less HP but more torque, great for a pulling truck, crappy for the rest of us.

Spent about 5 minutes on this, feel free to add more if you see fit, I know I missed plenty of issues, these are just the first 10 that came to mind with quick explanations.

 

and cracked dash.
and death flash.

 

Weak torque converters.

 

I can agree with 1,3 and 9 cracked dashes and the deathflash. I do not have issues with any of the other listed things.
Especially 10, I get 17+mpg on a 5.9. Although I have heard of all the other problems I just have not had any issues.
I would like to add this though
poor balljoints

 

Squishy brakes.

 

Poor front end parts.

 

My Magnum Engine'd truck gets good gas mileage


This is my current biggest issue.

But the bores look like this, so overall it's a win.


140k mile stock internal motor.

 

Design flaw: General discussion questions in the tech section of the forum.

 

thse of us with 4 wheel drive and 4.10 rearends are not getting that mileage. Your 3.55 rearend 2WD should get 17 MPG.

 

Gas mileage isn't an issue or design flaw, it's just the way it is.

When these engines/trucks were designed nobody gave a rats *** about gas mileage, plus it's a 3 and a half ton truck, what do you expect.

You accepted gas mileage when you buy a Dodge, they've always been known as gas pigs, much less a 318 or even 360.

I don't think gas mileage is a design issue