I have a 2007.5 Dodge with an auto (68rfe) do you have any thoughts on these as to what they can handle for hp/tq? What do you think about "electronic" mods, H&S overdrive programming for example?..

 

I would love a 68 in my truck ..... wonder just how hard that would be to accomidate ?

 

Ok a quick question to add to your count. An old mech. tale says that if a previous owner never changed tranny fluid in the truck you just bought, and it has 200,000 miles or some high number your better off not changing fluid ever because it will soon ruin your tranny.
When pressed nobody can say exactly what will happen to cause failure. Can you opine about this. I have heard this from several fleet type mechanics, but they were not transmission specialists. thank you
dave

 

Here is exactly what happens. New trans fluid has a high detergent level to help keep stuff in the pan and not sticking all around the inside of the tranny. A reason the magnet is so important becuase when new fluid is kept in place it washes all the metal and clutch to the pan and in turn a good magnet will catch most of it so the filter won't clog. When u take a neglected trans it gets all that stuff and it starts to stick all over then u change the fluid and stick the new detergent in there and it washes all that crap back to the pan and it starts clogging the filter any screens in place in the valve body the solenoids take a beating with stuff sticking to magnetic parts that throws resistance levels off then it won't work right. High pressure low pressure stuck valves bam it burns up. A reason the flushes are ao bad it does the same thing just faster. I have seen a car get flushed and not make it down the road and back home. Most times that is a death wish. I have done it but after the first change did two to three more complete filter fluid changes over the next 500 miles. Basically kept opening up until it looked clean but sometimes it can take a while for stuff to bust loose. The best way in like a 48re is remove the valve body and clean it by hand with brake clean then spray up in the trans let it run back out as u can get up around the case in the corners where metal deposits and bushing wear can build and catch it all then before you even rerun the trans. Not all are that easy but if u can access it then clean it that way is the best way. I also advise changing electronics soon after a change just to be safe. I keep like 8 sets on hand of dodge re trans solenoids just for that reason to sell and recommend to people doing services that are over due. Hope this explains is for you.
Joe

 

thanks for info. Would it be a good idea to place a strong magnet on pan for awhile before any service to collect as much crap as possible first?
dave

 

The input shaft, UD shaft, OD shaft, output shaft, UD clutch, OD clutch, 2C clutch, overrunning clutch, and the entire planetary geartrain were all designed to handle the 650 ftlbs of torque from the 6.7-liter.

Also, pump capacity was increased to improve fluid flow through cooler, greatly reducing overall transmission heat. The 68 was engineered from the ground up and “supersized” to match the power stats of the 6.7-liter Cummins.

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The interface to engine is similar (bell housing bolt pattern), but the 68RFE uses a separate transmission controller. The 68RFE controller interfaces with the engine controller for exhaust brake operation, etc. Therefore, retrofitting the 68RFE into a 5.9-liter truck is not feasible due to incompatibility with the 5.9-liter engine controller. Also, the 68RFE is fully electronic compared to semi-electronic 48RE.

 

Not only that but they make a in line filter that has a magnet on the outside of the case that works great for something like that just run it a few days pull it and service it.

 

RE: fitting a 68 into a 5.9:
With enough money, anything is possible. Someone out there has made a tranny controller for that application. it might be a one off, but it's probably been done.

 

Sorry didn't get a auto notice about the 68rfe question showing up. I build both transmissions and while they both have a bunch of aftermarket parts available I see a lot more broken 68rfe trans in big trucks over the 48re. On the inside the 68rfe is just a 604 transmission that the parts are bigger. It even uses the same type valving in the valve body. So a trans that was designed for a mini van they have taken it enlarged the parts and put it behind quadruple the torque load. The 48re is a copy of the famous 727 which was behind hemi big blocks drag raced for years in near stock forms and lived behind highly modified motors. So from the ground up the 48 started as a better trans. We get a lot of these over the road guys through out shop that use their 3500 duallie to tow huge car haulers something u would see behind a semi almost pulling in upwards of 8 cars on the back and they can see 100k miles in a few months. The trucks are crazy modified. Banks parts big turbos programmers one even has some bigger displacement engine in it and the 48re models 07 down are the preferred for this job. Besides the 68 just failing as a whole and burning up they tend to break planets and input shafts. The 48 will normally have a gov pressure sensor issue then lose pressure and inturn burn up. Failure is caused by electronics that were left unchanged too long. The way to have this not happen is go to a gm style pressure sensor by dnj. It is more reliable that way and way less failures. I know this is long winded I could go on and on I build these every week I specialize in the larger diesel trannies but build everything. I personally own a 2500 chevy with an Allison they just don't break I do one or two a year at a shop that does 100 different models a month. This will make some people that have paid for a major rebuild sick but and dodge rfe model trans is bought as a cut out. A low mileage working unit and taken apart cleaned and resold. They normally fail so bad they are too expensive to rebuild so we scrap them. The 45rfe is bought for 40 bucks. This is a working trans. The 68 is 100 to 200 depending on where they get it. That is how many are floating around in salvage yards. We can't touch a 48re core for under a grand sometimes buy broken cases with good guts at 1000 bucks. When fresh built right they just live a long time. So for anyone to even want to stick a 68 in place of a 48 just baffles me. Yea two more gears but that alone doesn't justify the swap as the 48 is the much better trans. I also have a 07 Tahoe with a 4l60e. They are known to break and not be the greatest for big power. I am building a 6.2 with a supercharger for it and know in that heavy of a truck it will be breaking planets and stripping the drum. So I am updating it to the 09 6l90e which is 100% stand alone from the engine. When you have the tcm on a stand alone from the ECM anything is possible. I have seen the 6l80 or 90 I'm camaros and corvettes behind 1000 rwhp live so going that direction makes sense. The 68rfe has terrible problems wearing pumps and valve bodies quickly causing flow issues with cooling and pressure just not what u want in a big truck hanging over your head. Why we replace and don't build them from customer cores. And again all over the place here watching tv and doing this one phone. I just like to go with what is proven to work it is what always seems to work out best.

 

you're telling me that a 68rfe, a transmission put into a rwd truck, is a bigger version of a 604?
a transaxle dating back to the 90s?

I think you're getting the 42RLE, and 45RFE mixed up. . . Honestly. the RFE family was introduced in the late 90s. The RLE was a heavily modified ultradrive that was tossed into the Jeep Liberty.

the 68RFE is a heavily modified 45RFE/545RFE.

I could be wrong though.