08 Manual or Automatic

[jraker]

Please help me understand something. For years the Auto was always the weak leak with the 5. 9 and now suddenly the Auto is stronger. So the new engine has more HP with the Auto than the Manual. However is there really a difference with the amount of waste through the Auto? I saw Dave Smith had a pretty sweet 08 manual for sale which is configured just the way I want. I am still sceptical on the auto especially after having to pay for my 47RE to be rebuilt. So is the manual that different than auto in terms of power? I don't want to chose the wrong option again. Please advise. I have a new horse coming in the spring and who knows how big a trailer we will get. I still have my 01 and rebuilt the starter contacts yesterday. It has 158k miles on it but things have been breaking (over 2k in repairs this year) lately. Left me stranded for the first time, two weeks ago when I was out shooting. Lost a lot of confidence in it that day. People say stick with the 5. 9 and count the blessings of not having the emissions on it. Sorry for the rant just on the fence about buying a new truck.

 

[Simplysmn]

Well best bet is drive a auto and then drive a stick IMO I love the auto and would never buy a stick {Bad knee's}with the new auto you can shift on the fly and also with exhaust brake and tow haul mode it work's Great Got close to 48,000 out of first set of front pad's My truck has over 55000 miles in 2 yr's Trouble free and Totally stock

 

[HBarlow]

The new six speed automatics, MOPAR and Aisin in the C&Cs, are tough, reliable, and work great with the engine and exhaust brake. With six forward speeds and two overdrives the automatics provide the best of both worlds. You can use the toggle on the shifter to control the gear you want and when it shifts, and you have great low gear for load starting. Fifth gear, first overdrive, allows highway towing of heavy trailers and second overdrive provides a very low rpm for fast highway cruise. They're hard to beat.

There is a reason Dodge limits torque and horsepower on the G-56 trucks and the dual mass flywheel assembly installed on manual six speeds is known to be troubleprone on higher mileage trucks used for towing or hauling.

I have not read or heard of a single problem so far with the automatic six speeds.

Your money, your truck, your decision to make.

 

[5ducksinadodge]

I recently purchased my 09 with the 68rfe and I pull a 15,700 pound 5th wheel. . I have pulled it so far only 800 miles, and I have to say it pulls great and I really like the manual toggle on the lever to choose what gear I want or keep it in that gear a little longer to pull a hill. The engine is very strong and I would not even consider a manual transmission. I read in the archives an article where the staff here had some questions for the engineers at Dodge about the workings of the 68rfe. One of the questions was how this transmission compared to the Allison. Basically, in a nutshell, it was very close with the exception of some gearing and pressures within. I don't remember the article number, but if you go back into the archives, you will see it. Lots of luck. . gary

 

[DGamelin]

I have a manual, in 04 I thought they were tougher. The new autos with that double overdrive allows you to run a 4. 10 and keep the rpms in check, 6th gear is tall, the new (trans) gear ratios are great, I also think the new autos are tougher then ever. My truck has a trailer hooked to it 90% of the time. I will be looking for a C&C with that Aisin next spring. I agree with the guy up top drive them both, good luck.



_________________________

93 250 2wd xc 354 auto 264k

04. 5 3500 4wd cc dully 373 6speed 87k

 

[gsbrockman]

So the new engine has more HP with the Auto than the Manual. However is there really a difference with the amount of waste through the Auto?

In September of 2008, I had my truck on Dunbar's Dyno (Diesel Performance Motorsports, Atlanta GA) and with just an H&S Stage 1 DPF Delete and an AFE Stage II Magnum Force Intake w/ProGuard*7, the ol Blue Bus put down 312/564 to the rear wheels. I wasn't expecting it to even break 290's based on what everyone else "thought" it would do.



These trucks do great stock and the 68RFE does a great job of putting the power to the ground IMO.



Greg

 

[jraker]

Sounds like the Auto is the way to go. I just wanted to make sure this time. I did have one more question on the Manual. Since it doesn't have the factory EB, does it see more Turbo cleanings? Isn't that one of the reasons you always want to keep the EB brake on to keep the slide clean from the EGR? Just curious.

 

[MullenaxM]

I have seen little or no problems with either the 68RFE or the Aisin transmissions.



Good stuff!!!



Mike

 

[Hoefler]

All 6. 7s come with the exhaust brake from the factory, manual or auto.

 

[HBarlow]

The misunderstandings about which trucks have an "exhaust brake" comes from the fact that none of them actually have an exhaust brake.

Yes, that's what I said. No ISB6. 7s have an exhaust brake in the way we formerly thought of an exhaust brake.

All ISB6. 7 engines have a variable geometry turbocharger which, when it closes the nozzle, performs the identical function that an external exhaust brake formerly performed when one was added to the ISB5. 9 engine as an aftermarket accessory.

 

[pcarlson]

For folks that know, isn't there higher rpm's with the manual which also knocks mileage down a little.

 

[HBarlow]

Yes, you are correct. Overdrive (6th gear) in the manual G-56 transmission is lower and spins the engine at higher rpm for highway cruise than either of the six speed automatics.

 

[RVTRKN]

For folks that know, isn't there higher rpm's with the manual which also knocks mileage down a little.

Yes, but I chose to shift when I want, and with a 3:73 rear, its not that bad. I've pulled with it heavy at 22K GCVW, and never looked for seventh.



There is another advantage with a manual that is hardly ever mentioned, and that is the extra heat generated that ends up in the radiator, with an auto. Just pulled that weight over both directions on the Grapevine in the heat and never heard my clutch fan come on, at 55 MPH.



Extra heat generated = HP loss

 

[WStephens]

The later G56 transmission have a higher set of gearing than the earlery G56 transmission so they do not have the same final drive gearing as the automatics with 4. 10 gears. Where my truck with 3. 73 gears and the G56 has the same final drive as the automatic and a 4. 10.



It really has not been a problem for me I am comfortable with the gearing of my transmission. I have towed in the Rocky Mountains and it did just fine. I do not like the dual mass fly wheel but it is much better than what my 90 F250 had so when it is time for another clutch I will upgrade with an new fly wheel.

 

[HBarlow]

The later G56 transmission have a higher set of gearing than the earlery G56 transmission so they do not have the same final drive gearing as the automatics with 4. 10 gears. Where my truck with 3. 73 gears and the G56 has the same final drive as the automatic and a 4. 10.

It really has not been a problem for me I am comfortable with the gearing of my transmission. I have towed in the Rocky Mountains and it did just fine. I do not like the dual mass fly wheel but it is much better than what my 90 F250 had so when it is time for another clutch I will upgrade with an new fly wheel.

Sorry, this is not true. You're comparing apples and oranges or comparing your G-56 to the old 48RE four speed automatics. The original poster is not talking about buying a new 48RE, he's considering an '08 with a new MOPAR six speed automatic which has two overdrive gears.

 

[nanook]

Only manuals for me... . on snow and ice the manual with pacbrake is perfect.

 

[WStephens]

If I was going to buy a new truck I would still get a manual I have no intrest in having another automatic.

 

[TLane]

Engine speed vs RPM

Here's a table I did from a spreadsheet that shows the engine RPM at various speeds, with different transmission gear ratios and rear end ratios. I think these are the stock tires that came on my truck. Unless I made a typo or something, this should give you an idea of the differences. I think the auto typically comes with the 3. 73 rear end but the manual typically comes with the 3. 42 rear end. Of course, just about any combination could be in your truck.





Tire 654Revs/Mile Michelin LT235/80R17E = 654



Rear Axle Ratio... ... ... ..... 3. 42

... ... ... ... ... ... ... ... Direct... ... 5th, Auto... . 6th, Auto... . 6th, Man

... ... ... ... MPH... ... ... ... . 1... ..... 0. 816... ..... 0. 625... ... ... . 0. 79

... ... ... ..... 50... ... ... 1864... ... ... 1521... ... ... 1165... ... ... 1472

... ... ... ..... 55... ... ... 2050... ... ... 1673... ... ... 1281... ... ... 1620

... ... ... ..... 60... ... ... 2237... ... ... 1825... ... ... 1398... ... ... 1767

... ... ... ..... 65... ... ... 2423... ... ... 1977... ... ... 1514... ... ... 1914

... ... ... ..... 70... ... ... 2609... ... ... 2129... ... ... 1631... ... ... 2061





Rear Axle Ratio... ... ... ..... 3. 73

... ... ... ... ... ... ... ... Direct... ... 5th, Auto... . 6th, Auto... . 6th, Man

... ... ..... MPH... ... ... ... ... 1... ... ... 0. 816... ..... 0. 625... ..... 0. 79

... ... ... ..... 50... ... ... 2033... ... ... 1659... ... ... 1271... ... ... 1606

... ... ... ..... 55... ... ... 2236... ... ... 1825... ... ... 1398... ... ... 1767

... ... ... ..... 60... ... ... 2439... ... ... 1991... ... ... 1525... ... ... 1927

... ... ... ..... 65... ... ... 2643... ... ... 2156... ... ... 1652... ... ... 2088

... ... ... ..... 70... ... ... 2846... ... ... 2322... ... ... 1779... ... ... 2248





Rear Axle Ratio... ... ... ..... 4. 10

... ... ... ... ... ... ... ... Direct... ... 5th, Auto... . 6th, Auto... . 6th, Man

... ... ..... MPH... ... ... ... ... 1... ... ... 0. 816... ..... 0. 625... ..... 0. 79

... ... ... ..... 50... ... ... 2235... ... ... 1823... ... ... 1397... ... ... 1765

... ... ... ..... 55... ... ... 2458... ... ... 2006... ... ... 1536... ... ... 1942

... ... ... ..... 60... ... ... 2681... ... ... 2188... ... ... 1676... ... ... 2118

... ... ... ..... 65... ... ... 2905... ... ... 2370... ... ... 1816... ... ... 2295

... ... ... ..... 70... ... ... 3128... ... ... 2553... ... ... 1955... ... ... 2471

 

[TLane]

*sigh*
30 minutes getting Excel to format it like I wanted, then posting it removes all the spaces!

 

[HBarlow]

TLane,

You must have mislabeled the columns. The tables don't make much sense as they are. I don't know what transmission is labeled direct 5th. You show two different rpm readings for "auto 6th. " Was the third column to the right supposed to be labeled as 5th gear in an automatic?