LJ 4 speed auto vs 6 speed manual

[Steel City 06]

The OPDA stands for oil pump drive assembly. It's a part that was poorly designed from the factory, and tends to go bad early in the 05/06 models. When it starts making noise it must be replaced before it fails, or you will lose oil pressure.

It's a $109 part and takes 20 minutes to replace. Most 05/06 owners do it ahead of time as a precaution. The redesigned Crown unit generally lasts without issues.

Replace it when you buy the Jeep and never think of it again.

The PCM issue is a hard shift issue that presents on a select few automatics.

 

[Sparkey1821]

The OPDA stands for oil pump drive assembly. It's a part that was poorly designed from the factory, and tends to go bad early in the 05/06 models. When it starts making noise it must be replaced before it fails, or you will lose oil pressure.

It's a $109 part and takes 20 minutes to replace. Most 05/06 owners do it ahead of time as a precaution. The redesigned Crown unit generally lasts without issues.

Replace it when you buy the Jeep and never think of it again.

The PCM issue is a hard shift issue that presents on a select few automatics.

And this was for manual and automatics I’m assuming?

 

[Steel City 06]

Ok I didn’t know this I was only thinking in that mid set in regards to economy/fuel mileage as the added weight of the 35’s.

You can always get narrower tires in 33 and 35. The width of the tire probably has just as much impact on fuel economy as the height. A good all-terrain would be marginally more fuel efficient than a mud terrain, and be quieter and have better on-road manners. The all-terrains only suck in very deep mud and some types of rock crwaling.

Load range C tires generally aren't excessively heavy. They're usually found in 15" and sometimes 17" rim sizes.

As long as you regear properly for the size of tire you choose to run, you can optimize for either 33 or 35 inch tires. Optimizing for both is a bit trickier, and will require compromise.

 

[Steel City 06]

And this was for manual and automatics I’m assuming?

The OPDA issue applies to all 2005/2006 Wranglers with the 4.0.
My recommendation is don't worry about it. It's super easy to replace.

The PCM issue applies only to the automatics. The issue itself is rare, so I wouldn't worry about it too much either.

 

[Jerry Bransford]

The OPDA issue applies to all 2005/2006 Wranglers with the 4.0.
My recommendation is don't worry about it. It's super easy to replace.

The PCM issue applies only to the automatics. The issue itself is rare, so I wouldn't worry about it too much either.

The OPDA is relatively (not super) easy to replace but replacing the OPDA doesn't always fix the problem for long or rarer yet, permanently. Many have replaced the OPDA several times after the problem reoccurs.

The 05-06 PCM/auto transmission problem isn't that rare, I see posts about that issue all the time in the 3-4 Jeep forums I browse through.

 

[mrblaine]

My thoughts exactly. I wouldn't touch an 05/06 with an automatic but I'd only go with an automatic if it was a 2004 or older.

I'd take one all day long and twice on Sunday.

 

[mrblaine]

Automatic going up-hill, so you don't have to shift.
Manual going down hill, so you can use engine braking instead of riding your disc brakes.
Did that answer your question?

I hear that shit all the time. If you are going downhill that is steep enough that you are using either your brakes or the engine, you're in 4 low. If you're in 4 low, the front and rear axles are tied together through the t-case and all 4 tires respond to either the engine or brakes. That and geared correctly, the auto generally has to have some throttle input on steep downhills or it goes too slow and the manual guys ride up on your ass. Happens to me all the time.

 

[mrblaine]

I'm a manual fan. For all the reasons you mention. I've had a few automatics and almost every one has left me stranded. And bumper to bumper stop & go traffic is not an issue since I drove semis for years with 18 gears to pick from in rush hour city driving.

But the TJ 4 speed automatic is an anomolly. The massive jump to a 0.69 overdrive means gearing, bigger tires are a huge compromise. I honestly like TJs with the old 3 speed automatic, no overdrive and it is pretty much bullet proof.

If the choice were clutch vs 3 speed automatic, I'd say pretty much personal preference. But for me, I'd never want the 4 speed automatic.

I've owned nothing but automatic transmission equipped rigs 20-30 of them. Only one time has one left me walking. That was due to me being preventative and having the trans in the Dodge tow rig upgraded. The 1200 dollar billet triple disc torque converter took a shit. I should have left it alone and I'd have a perfect record. I have 7 with autos right now. I'm not the least bit skeered one of them will leave me walking.

 

[mrblaine]

I was really hoping that you and @mrblaine would chime in on this thank you for your input. I probably won’t be doing any heavy crawling in the near future I’ve read a lot of what y’all have said in regards to the autos and that’s what got me thinking and led me here.

I'm fairly pragmatic to a fault. I believe I can fix most stuff so the 05-06's don't bother me in the least. I build a lot of them for folks. If there were an issue that couldn't be overcome, I wouldn't do it. I am also bored at the moment taking a break from some construction around the house or I wouldn't be replying since I have grown to despise the bullshit that manual versus auto threads turn into. I've only read the first 6-7 replies and its already going right in the crapper.

 

[mrblaine]

Ok I didn’t know this I was only thinking in that mid set in regards to economy/fuel mileage as the added weight of the 35’s.

If fuel economy bothers you enough to even consider transmission choice, find another vehicle to drive. A Jeep is not for you.

 

[mrblaine]

And this was for manual and automatics I’m assuming?

Yes, but there is another issue on the 05-06 manuals in that the PCM is programmed poorly and there is a big flat spot at mid level acceleration that drives some owners batshit. I've got one client with it and we tried 4 different PCM's in it trying to see if there were any better ones and they all sucked.

 

[Sparkey1821]

If fuel economy bothers you enough to even consider transmission choice, find another vehicle to drive. A Jeep is not for you.

I’m really just looking for what’s going to give the least amount of headaches hit in my pocket book in the long run? Not really necessarily fuel economy but cost to repair/reliability etc. until I read some of the forums on the auto subject with your inputs and Jerry’s input I was all in 100% for standard transmissions now I’m at least considering an automatic just trying to weigh the pros and cons of the automatic.

 

[billiebob]

I've owned nothing but automatic transmission equipped rigs 20-30 of them. Only one time has one left me walking. That was due to me being preventative and having the trans in the Dodge tow rig upgraded. The 1200 dollar billet triple disc torque converter took a shit. I should have left it alone and I'd have a perfect record. I have 7 with autos right now. I'm not the least bit skeered one of them will leave me walking.

Absolutely !! ^^^^

Horror stories are out there for every choice. Pick the choice you are most comfortable with. But I've never done maintenance on a manual transmission beyond an oil change every 60K miles. I just put a new clutch in my TJR at 170K miles. Not because it needed it, But because the shop said.... might as well since we are putting in a new engine.

 

[steelhd]

I’ll be using as ... and occasional off-roader.

Therefore an automatic. And an 04.

 

[mrblaine]

I’m really just looking for what’s going to give the least amount of headaches hit in my pocket book in the long run? Not really necessarily fuel economy but cost to repair/reliability etc. until I read some of the forums on the auto subject with your inputs and Jerry’s input I was all in 100% for standard transmissions now I’m at least considering an automatic just trying to weigh the pros and cons of the automatic.

Your only manual option is the NSC 370. It isn't special or even desirable. This does a decent job of explaining the problems.

But again, if I wanted a manual TJ Unlimited, that wouldn't prevent me from getting one. I could swap in the AX-15 or NV 3550 in my sleep practically.

 

[mrblaine]

Therefore an automatic. And an 04.

Either can be used to build a rig that will go the same places with the same ease. It just costs more to build the manual.

 

[Alex01]

It just costs more to build the manual.

Why is this?
Are you chasing crawl ratio with an atlas 4 speed?

 

[mrblaine]

Why is this?
Are you chasing crawl ratio with an atlas 4 speed?

When I reference high levels of capability, it should be understood that they will be able to play in Johnson Valley with no issues. It takes at least the 5-1 ratio Atlas to do that. I don't mess with the 4 speed stuff, so the 5 or 6-1 is fine with the appropriate gearing in the axles. 4-1 isn't enough so an Atlas or similar is required. I can take the same Jeep on 37's and it will follow the one with the 6-1 around all day long out there with the NP 231 and the auto. I'd prefer it to be a 4-1, but it isn't required. I don't chase crawl ratio or wheel travel.

 

[FF_Jeep]

I’m really just looking for what’s going to give the least amount of headaches hit in my pocket book in the long run? Not really necessarily fuel economy but cost to repair/reliability etc. until I read some of the forums on the auto subject with your inputs and Jerry’s input I was all in 100% for standard transmissions now I’m at least considering an automatic just trying to weigh the pros and cons of the automatic.

Auto vs manual really has no weight on your cost of ownership with a Jeep TJ. It's personal preference. Get what YOU want. I prefer a manual Jeep so I bought a manual Jeep. If I was putting an LS in a Jeep it would be an auto. Again, personal preference.

 

[Sparkey1821]

Is this a good deal at $14k? If I did change my mind and go for the short wheel base afterwards and decide to sell will I get my money back?

2005 LJ
94,500 miles
6 spd manual trans
6 inch long arm lift
4:88 gears
set of 5 35x12.50x15 Cooper STT pros 80% tread
lots of new suspension and steering parts installed professionally.