ktmrdr85

I really want to know here. If I was considering getting a Dodge truck and the options were between one with a 5.9 and a 6.7 and they both had automatics, what would the 6-speed 6.7 automatic give me in terms of benefits.

I only tow a mastercraft x-star wakeboard boat as the absolute heaviest thing that I tow.

My truck isnt modified. Plus, statistically, the 5.9 motor gets better fuel mileage then the 6.7 anyway.

So, what are the benefits, if any, of having a 6-speed automatic.

From everything I have seen, the 48RE is a really stout auto anyway, right?

Dodgezilla

I've owned and ridden in several trucks with stock and modified 47REs and 48RE transmissions. Every single one has just seemed like it didn't shift where your brain thinks it should. They either shift too quickly, they wait too long to shift, or they hunt for gears and shuttle back and forth. It really irritated me. When I was looking for my truck I was not sold on the 6.7 but the 6 speed auto seemed awesome. The 5.9 was what I was initially looking for but I didn't trust the 4 speed auto either. In the end I decided to get the 6.7 with a warranty and let the dealer deal with it if I had problems. I've seen a couple posts where guys that don't own a 6.7 complain that they have a loose converter but my trans works great and tows my trailer easily. The only drawback to a 6.7, for me, is the mileage. Plus I'm sure there will be better converters out for them in the future if needed......

JP-4.5

I am not sure what year 5.9 you were looking at? All the emissions stuff on the 6.7 is the part I would not want to deal with. The 6 speed would be awesome I have no doubt. The 5.9 was the reason I purchased a Dodge and am hoping for many years of service from it. I did not like my 4 speed from the day I purchased it. It worked and caused me no trouble but I did take it easy. I ocasionnally would tow a hobby car and utility trailor that are very light and/or a camping trailor that was 6k with the stock tranny. 80+k with stock tranny that I did 2 filter/fluid changes and did not have any failures. I really think that a converter added to the stock tranny would make a big change if the tranny was not going to be abused by whole shots or boosted launches.
Good Luck with your decison... Jeff

Jeff in TD

Some people are bothered by how an auto shifts, and other people seem to be able to pay it no attention...

Personally, I think the 48RE could really use more gears for heavy towing. When you take it out of OD, the RPM jump is pretty big.

Anyway, if you personally like how 48RE shifts, and aren't planning on towing anything heavy, I'd say go for it.

On the other hand, if you are like me and just don't care for the 48RE, I think I'd put up with the MPG hit to get the 68RFE, as long as it didn't get the really horrible MPG's some folks have talked about...

The one I drove seemed to read your mind, and if it didn't, the paddle shift switch is right there. Really worked well with the exhaust brake feature of the variable turbo.

Seems like many of the people reporting bad mpg have the earlier (07's) 6.7.

Dodgezilla, what kind of mpg's is your truck giving you, at what kind of speed?

GlennRMK

I think the 48RE could definitely use a lower first gear and a lower reverse. Something higher then 3.0 numerically. It would be nice to split the difference between 1 and 2 and have an extra gear.

I love the 68RFE's ability to be manually shifted via button on the fly. Thats nice! As well as the exhaust brake.

When is someone going to hook one up to a 5.9 and make separate computer for the transmission?

I like my 48RE, but the 68 RFE is way nicer.

PRO-NRA

You ca always get teh G56 and you can shift to whatever gear you think you should be at. You know that our CTD has so much torque very low that it is a very forging engine and it does not care what gear you are on it will move!

Jeff in TD

Yeah, I went 5.9 with the G56 myself.

Although it shifts nicer than my last NV5600 truck, it seems to make a bit more gear noise, and there is something about the feel of the clutch I just don't like (too soft of an engagement or something). Nothing that couldnt' be solved by the UPS guy with a box of South Bend stuff, I'm sure, but I haven't wanted to spend the money.

I also felt 6th gear was too low, but on my last empty road trip I got 20.5. Not bad for a 4x4 dually, so I guess the motor doesn't mind spinning a bit more.

Hintz

Like stated, the 6speed auto is a great tranny, but the 6.7 in front of it is hit or miss. With the 5.9 its hit or hit you can go wrong, but the 48re is lacking in a lot of places. IMO the 5.9 w/ the G56 is the way to go.

TexasCTD

I drove a 6.7 with the auto........it is SWEET!

But I also have been happy with my 48RE. My only complaint with it was the stock torque converter just didn't put the power to the ground and it would rev up just going up some minor hills. I don't have to worry about any of that now with my Billet DTT and triple disc TC. I love my built trans and wouldn't consider trading it for a 68RFE.

..

Hopper

I have both the 4-speed and the 6-speed autos. I love the lower RPM of the 6 on the highway (where I spend most of my time). The other place I love my 6 is in squirrely weather conditions where I can pick a desired rpm on the power curve and keep it close by using gears. I don't run any mods on the 6.

Where I don't like the 6, is the hunting. My 4 never hunts. Hills, valleys, wherever, it stays in a gear when it gets there untill I manually lose or gain speed. The 6 hunts quite often, especially around 70 mph (day-time speed limit on west Texas back roads). Even slight hills will cause a downshift. The truck also gets some crazy surges while in reverse. This caused me to loose control of the truck once, because it fights the brake on an upward surge. Only way to stop it is to stand on the brake. Truck's been this way since new. Almost acts like driveline lash without all the associated noise.

Dodgezilla

Keeping it in "D" or 6th gear is almost too high of gearing and your RPMs actually can get too low. So, I would agree with Hopper kind of. I haven't really had that issue on the highway but I do if I am just driving around town. What i usually do is manually put it in 5th gear or 4th. If you aren't going faster than 45 mph then your rpms stay around 1800-2000 which we all know is the sweet spot. Running around town in "4" is perfect for throttle response.

As far as mileage, I'm getting about 13.5 in town and 16-20 hwy depending on how fast I drive. Towing mileage is not good for me at 8-9 mpg. I only have 6000 miles on mine though. I'm hoping for an increase at around the 10-12000 mile mark but many guys have stated that the 6.7s don't get that break-in mileage jump that the 5.9s get. We'll see....
My 07 5.9/G56 got 14.5mpg city, 16-20mpg hwy, and 10-11mpg towing. Not much better than this truck gets and the 07 had 30,000 miles on it.......

If I was offered a brand new 5.9/48RE truck just like my 6.7/68RE for an even trade, I believe I would keep my 6.7.......

cdhd2001

I test drove both in 2007 models last summer. All the emissions problems and low mileage with the 6.7L scared me away.

Personally, I think the 48RE shifts way better than the Allison 1000 I had before (see sig). However, I don't like the "regular" setting. I do love the T/H mode and drive in that setting 24/7. Shifts like a standard from 2-3 and 3-4 and will hold down to 2nd when slowing and going in traffic. It will have an ocasional hard down shift, but not often (unlike the allison, boy did they mess up the trans shift in my opinion).

Really happy so far and it does a good job towing my 5th wheel. I never notice the "missing" gears.

BroncoAZ

I recently purchased my CTD with the 48re. I came out of a Titan with the 5 speed auto. The Titan't trans was ideal for the application. My first week of ownership impression of the 48re is that it works well in the diesel application. I haven't loaded up my trailer yet, but it should be fine. The only complaint I have, probably not transmission related, is what happens when I am on the highway and have to slow down. When I hit resume on the cruise control at say 60 mph to get back up to 70 mph the truck downshifts to third, revs to 3000 rpm, then shifts to fourth. If I simply press the accelerator to half throttle the truck accelerated from 60-70 faster, and without a shift.

Sofar I've been driving this truck like an old man...