From the pictures I have seen the pieces are bigger, but, I also see a lot of 4 pinion planetaries, a lot of 4 skinny disk clutch packs, and a lot of what looks like aluminum parts. That has been the down fall of the 4XRE/RH trans line, in addition to low line pressures. I suspect as much TQ management that the Allison implements it is not up to monster amounts of power.

A lot of my skepticism about the Ally stems from the gales of laughter induced by my asking several Allison techs how the 1000 series would fair behind a 400 HP 1000 ft\lb 12V. While the Ally 1000 is used in the motorhomes behind an ISB, the engine is managed by the software and detuned. I guess maybe they knew what they were talking about back then.

To your original question, the 48RE is just outdated when compared to the newer transmissions. Six speeds are definitely better than 4 when it comes to putting the power down consistently an making a "fast" truck. However, the 48RE is the only one that makes a "work" truck work consistently. Even with all the little goofy things it is still a reliable tough unit that can easly be upgrade to bullet proof for about its cost new.

I sincerely hope the new autos, A68RC and 68RFE, have as good a record as the 48RE and take as much punishment. If not we will be back to the same old song and dance about an Ally in a Dodge.

 

The 48RE is a good tranny. That is, it's strong and reliable under stock or near stock conditions. I've got 90,000 on mine and it works just as well as the day I got it. I'm lightly bombed and tow in the mountains.

There are always people who can find a way to break something and then complain that it's weak. If you want 800 HP and want to race you'll have to upgrade.

I think the main problem with the 48RE is that it is WAY outdated and needs more gears. It's basically a three speed with OD added and made to shift very softly. First gear is too high and the OD shift is weird. It's a very old design and overdue for replacement. The new Aisen 6 speed may be just what we've been waiting for and I hope so. I love my '04 but if that new tranny is all it's supposed to be I'll be tempted.

But I'm not one to start slamming the 48RE just because it can't hold a bombed and raced Cummins. Of course the TC slips, it's supposed to slip. It's a fluid coupling and multiplies torque by slipping. Then it locks up for highway cruising and becomes more efficient.

There has been a lot of slow progress over the years with these trannys. When they went from the 2 speed to the 3 speed it was great. Then the OD became an option (?!). Sheesh, who wouldn't want it? And the lockup converter, another cool idea. But now it's time for a near seamless 6 speed design. But they are still blowing it by making them with overdrive. The top gear should be straight through for best efficiency and just have a very high differential ratio like 3:07 or 3:23. And the first gear should be very low to get the big loads moving or for four wheeling.

Wetspirit

 

You're saying the 4-pinion planetaries and skinny clutch packs are in the Allison?

 

Here:

http://www.transmissioncenter.net/allison1000.htm

 

That woud work fine for cars, SUV's, and light duty applications but it is worthless for trucks in the GCVW of the 2500/3500's. Take look at medium duty trucks and see what the gears are. The trucks that can use a ratio in the higher ranges are much more massive and heavier than is possible in a light duty range.

Its a simple matter of physics with the final drive ratios. While the engine is capable of the leverage the drive train parts cannot stand the strain. A much better effective ratio is achieved with lower gears and overdrives that could be done with higher gears and no OD while using smaller more cost effective pieces.

 

It's not a matter of leverage. The torque being delivered in the upper gears to the differential is far less than in the lower gears. It's a matter of extra gear sets being involved in the drivetrain. With an overdrive in the tranny there are extra gears running instead if just locking all clutches together and making a straight through drive. Each extra gearset costs about 3% of the energy delivered. And with an OD the prop shaft is running faster than the engine which increases its resistance and wear.

Originally, when OD trannys started becomming popular, manufacturers also offered 4 speeds. So the base tranny was a 4 speed and the optional tranny was a 5 speed with OD. The diffs were the same, just the tranny was different so it was a marketing thing that didn't require them to do anything other that put in the 5 speed. Many people think and OD will automatically produce better mileage but it's the overall final gearing that matters most, not whether it's and OD. So a straight through trans with the same overall gearing to the wheels will deliver better mileage than an overdrive tranny with the same overall gearing to the wheels because there are fewer gearsets running and the propshaft is turning slower. It's a small difference, but a difference.

Wetspirit

 

I have found in the past that if you set your toy up for towing....if you ever tow....the trans will last and perform much better...longer......I always add a superchip...larger trans cooler in line with the radiator.....and a extra capacity trans pan......and a trans gauge.....ALL for about $ 1100 bill...my labor...trucksalesdave...georgia

 

Well I can say that about 4 month's ago you couldn't GIVE me another Auto Tranny behind a Cummins!! I have had the 47re and the 48re------while the 47 never left me stranded it did leave me wishing for a better Tranny as far as performance in shifting and Towing. The S.O Engine didn't help either! The 48re in my Dad's Truck and my best friends truck have worked great! I can tell that they slip while under heavy load but they work day in and day out---------------so here is my story----------2800lb car on a 1100 pound trailer Toasted the 48re in my previouse 06-----man was I ******!!!!! I traded the truck after many, many, attempts to fix it at the Dealer's!!!!! I have the new G56 Manual and would not go back at this time. I just prefer the sense of getting what I want in power to the ground while towing instead of the searching and lugging that the 48re did! I really hope that the new Orion/46re Tranny will be a God Send for these trucks in performance and Towing. I know that 2 extra gears are going to be better but Both of these new gears are going to be OD sets. Time will tell, and I hope that it is good for Dodges sake. -----There are to many 48re's out there that go at it day in and day out and never have a problem, but not mine for some reason. This has nothing to do with driving skills or style. I have towed many, many miles in the Mountains and Hills of NC and the Eastern Sea Board to know that the Manual is right for me.----------------------The Allison in my opinion is just a better Tranny-----------more failures because there are twice the units sold every year compared to the 48re!! The newer Allisons will have fewer problems in the future. The TQ Shift that the Ford's run are great Tranny's to.

JB

 

Adding a superchip, is not going to prolong tranny life.

 

184k on my tranny..... same tc... just added a vb..... i like the tranny... seems to work fine for me!

 

I like the 48RE after I had it fixed at 47000 miles. The tranny was hard to take out of park and I got that fixed and after that was fixed it wouldn't go into reverse. The dealer rebuilt the whole tranny and also put in a different TC. I was told that DC had found that the TC was the cause of most of the tranny problems. Once they changed that and fixed the tranny I havn't had any issues with it at all. I now have 100,000 miles on it. And I tow a 3 car wedge on a regular basis. Only had the truck since May of 05.

 

now Im not saying one trans is better because those kinds of threads are worthless, but I think it is fair to say that the stock hard parts in an Allison are significantly bigger and stronger than those of a 48re, no? Billet input and output shafts for the Allison have literally been out like two weeks or maybe 3. Theres a reason its taken forever to put billet allison hard parts on the market No Limit (one of the 10 second duramax's) has quite a few 10 second passes and a buncha 11 second passes, they are running all stock trans hard parts and have 'only' eaten one output shaft.

I also proved that you can drop a 350-some odd pound allison from 4 feet onto a concrete floor and have it survive unscathed (well I needed to bolt on a new bellhousing but that was cheap)

the stock clutches are very big and have a lot of surface area, so with simple mods like a transgo they will hold a lot of power without going to the all-out Suncoast clutches and kolene steels. I dont know about planetary design and and steel hardnesses, but I do know the ally planetaries are huge and I have to pick them up with two hands.

now all that being said, I have no reason to say the 48re is a bad trans, other than the ratios and amount of gears not being very well suited for towing. When built they seem to take all the massive torque a modded cummins can crank out...anything that will hold up to that amount of power in a 7,000 pound truck is a darn good trans in my book.

JMO...

ben

 

I have the 48re behind my CTD, it seems 10x better than my 02 47 behind the 5.9 magnum, but that may be due to the Magnum being gutless for the weight of a QC 4x4.

I was told that the 47 has a training program to adapt to driver preferences? 60k on her, but she still searches way too much, she doesn't kick down when I want her to and then she kicks down when I don't want her to. Is she saying I'm indecisive and so that's how she was trained by me?

The 48 seems more consistent, my one disappointment is at freeway speed if she kicks down, she's at redline and wants to kick back up. CTD has plenty of torque in 4th, why kick down?

Isn't the 48re the same one used in the SRT10's?

I know they don't tow and haul, but 500hp/500tq and you know these guy's are using every bit of it that they can at most stop lights/on-ramps. I would be...

So how are they holding up in those?

 

Bigger maybe, stronger is subjective. Subject to whether its broke when you need it. If one subscribes to the theory "bigger is better" then the Ally is a dream come true. Check out the thread in the general diesel section about the Ally conversion and such. I suspect we are not hearing the whole story and, the reality is not quite as rosy as the dream state.

As far as the billet parts just starting to show up, could it possibly have something to do with the fact they have just figured how to get the Dmax to hold together long enough to make some decent power? no?

700 HP and 10 seonds behnd a Dmax is not the same as 700 HP and 10 seconds behind a Cummins. We know how far the 48RE can be pushed, how to build it, and how much it costs. The Ally is still proving itself behind the Dmax and still has the Cummins to deal with. When it does that THEN maybe it will be worth the consideration and significantly higher costs.

 

As with ANY automatic transmission HEAT is the enemy. Keep it cool and you should be fine. When backing with a load, use 4wd LOW. This will keep the transmission much cooler. I am quite content with my 48RE.