My 48RE is working good, but I started thinking: Will we soon see aftermarket kits that will fit a 68RFE or Aisin auto behind our 5.9's? I would love to try one out.

 

It all comes down to the demand. I am sure one day there will be a good demand for someone to do the R&D and it will happen.

 

There's a kit w/ a built 6-speed Allison that you can buy for around $10,000

 

There was a guy on here selling allison swaps for 6000. Thats one of reasons I joined this site was to learn more about that swap but that thread turned into a hot debate page! Which tranny is better, which is cheaper got kinda tense I dont know if it is still going or not but the guys name was gabe real nice guy I talked to him in person and email always got right back. Hope that helps

 

anyone have the link to the thread or know a link for this swap?

 

It seems that just about anything is possible if you are willing to do what's necessary.

The Allison conversion is very complicated and way over the top from what I read about the one guy that did it.

Some day, I hope, the Aisin 6 speed in the chassis/cab model Dodge Cummins may be relatively easy to retrofit. I'm surprized someone hasn't already done it and worked out a kit. It should be a bolt in and it would require a stand alone controller or computer with some modifications to ignore some sensors and the lack of the new turbo with engine brake, but OK, so what.

The Allison is a real pain and might not be any better, in the long run, than the 48RE because of it's shifting system.

The main reason I want something other than the 48RE is the lack of gears and the clunky way it works, plus having to spend $6,000. on it to make it handle the Cummins. Sheesh! But if you are not towing heavy and you have stock power the 48RE will go a long time.

 

$6k to build your 48, over $10k to do an allison. sounds like an obvious choice. install taller tires

 

I personally don't see what the big deal is with putting a six speed behind a
5.9. One will show up in the junk yard soon and someone will try it. Can't be more than a computer program to run the tranny and a shorter drive shaft, I suppose. Bellhousing should be close.

Dave

 

Since I purchased my 06 with the 48RFE, I have asking about installing the 68
RFE in my truck.

I finally got a reply back from a Tranny Shop in the Panhandle in Florida that said, they are working on it now. So, I thought I would pass it on. If and when it happens will come back here and let everyone know.

Dave

 

But if no one has created a "build up kit" for the 6 speed, then why would anyone consider placing it behind a bomb'd 5.9? From hear-say and reports the 6 speed auto doesn't handle any more power then the 4 speed... I bet the torque management on the 6.7 is ALOT more involved (detuning in low gears) then what they have on the 5.9. Sounds kind of like replacing an old penny for a new shiney one...

I could see some interest in the conversion, if the market came out with a reasonable upgrade kit for the 6 speed tranny first.

Not knocking anyones idea, just doesn't seem like an upgrade unless your talking a bone stock truck, but usually someone with a stock 5.9 wouldn't be interested in a major tranny mod.

 

Yep, about a 100 HP and the TQ and its at its limit. For somebody that wants the extra gears and keep the power and use reasonable it would be a great swap.

Forget thrashing and racing. The design of these heavy duty 3 planetary transmissions just won't work and stand up to speed shifting under high power. It will be no better than the Allison and just as expensive to upgrade for little gain.

NOTHING will ever match the E4OD and 48RE for easy of building and shifting ability in multiple uses.

 

I really don't think the reason for bolting up a 68RFE were a 48RFE was has anything to do handling HP and Torque above its designed limits.

This transmission has towing capability far beyond the 48RFE. 1st and 2nd gear in the 68 is lower than 1st in the 48. The 48 struggles to get the load moving unless you have a big rear ratio. The 68 has two overdrive gears. Fifth gear when mated to a 3.73 rear allows one to tow at the RPM's needed
to keep the load at 2100 rpms which is 65 mph. The load is off the tranny, EGT's are lower, and Tranny Temps are lower since its not under a heavy load. It would be like having a 4.56 gear behind a 48RFE.

When not towing one can take advantage of the second O/D gear (6th) to get the R's down to about what it is with the 48RFE. Otherwise with a 4.56 your mileage would be way down with the 48RFE.

Dave

 

The 68rfe has complete computer control built into it. This allows them to fully control the tranny along with the TM of the 6.7 engine to allow maximum transmission longevity. If I were to buy a new truck, no way, no way would it have those crappy 3.73 gears in it. I would only buy one with 4.10 gears. They offer those gears for a reason, towing heavy. By the way, my truck dosen't struggle at all to get the load moving, hence the built auto in my signature. $6000 dollars it not needed. Talk with Dave Georend. He won't sell you anymore than you need.

 

I'm going to put the 4.10 gears in my truck soon. They really don't cost that much. My truck came with the 3.73's. I tow at max now with the 3.73's.
4.30 is want I need. No one makes it. Hence, the reason I'm looking at the 68
as an option down the road. I plan to trade the current fiver for one with a GVW of 16,500lbs. (Carri Lite) Otherwise to get to the cruise rpm's I want to be at 65mph, I should go to 4.56 gears, hence no load, lower EGT's, and lower tranny temp.

Your not telling me anything I don't already know.

I should have just bought an 05 with the NV5600 tranny and 4.10 gears. Problem solved. Towed with the NV5600 for 9 years. replaced the clutch
at 185,000. Only reason I bought the mush box is the ole lady can't drive a stick when we're in a campground, when she wants to go somewhere.

thanks for your reply.

Dave

 

If you'd like more gears, an overdrive unit might be an easy 'no-computer' install. Gear Vendor and a few other make some fairly stout units. This might be an option if you'd like more gearing options.