wap

Just out of curiousity, how do these transmissions stack up agains each other in FULLY BUILT form?

One day I would like to drop a CR into a superduty and after looking at some conversion websites I dont know what trans to go with.

If I picked up a ford with a 4R or 5R it would be an easier/cheaper swap. Or if I get a CR with the trans behind it, same deal. I really want the allison but if I could get a 5R100 to hold 7-800hp I think I would like to go that route.

But I could pick up an earlier model superduty with a 4R100 or even a manual trans a lot cheaper and maybe make up the differance in price.

What do yall think?

IF I can ever afford to do this, the truck in question will be my go fast truck and I will detune the dodge and use it for daily purposes/tow rig.

LanceD

Dave Goerend told me he would take a built Allison 1000 over any built dodge auto any day of the week

ratsun

I have seen the insides of the 47/48s and the allison and there is really no comparison. The allison shafts and stuff are at least twice the size. I don't know about how they last stock but a built one has to be killer.

signature600

BUT, an Allison is screwy to shift...it needs to defuel the engine so it can shift halfway smooth. They have also broke some hard parts at the same levels the 47/48Re's have been breaking them!

I'd wait and see how the Aisin, or 68RFE hold up...those could be better options! I have also heard of some more "tinkering" with the 47/48 internals to make them even stronger...but I don't know enough about tranny's to find out what they're working on.

Mine should hold all I can throw at it for a while
Chris

wap

I was not aware the allisons had to defuel to shift.

This is a year or two away so its not like I am in a hurry, but if a ford trans could be made as tough and fast the 48re or allison, it would be easier to swap the cummins into a ford auto than a cummins and 48re, or cummins allison combo into a ford.

cumminsdriver635

Ill put it this way. I am not sold on the fact that the allison is as tough as it is made out to be. yeah, its a good transmission, but they cant handle shifts under full fuel unless they are built. my stock clutches in my 47rh have been holding locked full fuel shifts for quite a while now. I just think the allison is more hype than anything. I like the 48re pretty darn good myself. They seem to be a real good transmission. Give me a Goerend built 47rh and ill be happy

Eric

JoshH

All I know is I have run around 500 hp through my stock Allison transmission and it hasn't limped yet. I don't know what you guys are talking about on the defuel. I've logged several 1/4 mile runs with EFI Live and haven't noticed any defuel on shifts.

cumminsdriver635

If you are truely making 500hp, you must not beat it hard, because it doesent take much to limp one into 5th. Im not saying they are a bad transmission. They are just way too hyped up IMO.

Eric

JoshH

Trust me, I beat on it plenty. I dynoed about back in early December with a different setup. I got about 450 uncorrected and 480 corrected. I'm running a different setup now and it has more power. I'm thinking of going to a dyno event next month so I'll see what it says then. I have run a best of 13.68 @ 100.3 mph. I do have a problem with the 2-3 shift hanging and causing me to hit my rev limiter, but I believe it is tuning related and not a transmission problem. I'm surprised it hasn't limped either, but I have the 6 speed and they seem to be holding up better than the 5 speeds.

But for the record, I do believe people fly the Allison flag way too much (kind of like how Dodge guys fly the Cummins flag).

signature600

Really...is there another reason to drive a Dodge?? How about a better engine in a pickup??

I know you drive a Chevy/Duramax, and probably love it...but most of us drive Cummins, and love them. Cummins does seem to dominate most competitive arenas though

BTW, I'm not knocking the Duramax...I like them, they run good, and EFI live is the coolest thing to come along for the diesel crowd in a long time...but I like my 12v's

Chris

JoshH

I agree the Cummins is a great engine, and I was in no way trying to insult it. I was merely stating that people get very wrapped up in the Cummins on the side of their truck and fail to realize that it isn't the end all be all of diesel engines. Stock for stock I agree the Cummins is a much stronger engine that can take more abuse. I don't think anyone could argue otherwise, but when it comes to developing power I think the Duramax is just as good an option as the Cummins. I just wish we had the aftermarket support you guys do.

duratothemax

You dont understand. The allison is a CLUTCH TO CLUTCH transmission. The nature of its operation and the fundamentals of its technology do not allow full power through a shift. This is not a fault or weakness of "the allison transmission", its just the way it works.

Do you know just how an allison works? It has no overrunning clutches, no freewheels, no sprags, no bands. Its 5 clutchpacks need to apply and release in perfect timing so "handoffs" between clutchpacks are smooth. The transmission can not defy physics. Pressurized hydraulic fluid can only fill an apply piston "so" fast. That time it takes to fill and empty an apply piston is going to account for the extra time needed to shift. You absolutely CAN NOT have 3 clutchpacks applied at once in an allison. You will get a "tie up", where the trans tries to be in 2 gears at once. This will grenade a trans because all of the internals fight eachother. So two clutchpacks are applied and making a certin gear ratio. Then it comes time for a shift. It has to empty (release) those clutchpacks BEFORE it applies the next combo of clutchpacks. This has to happen in mere milliseconds. It is an INCREDIBLY difficult balancing act and feat that the transmission can shift as fast as it does.

The fact that the TCM can juggle all this and make it happen, while accounting for physical limitations (how fast fluid can fill passages and apply clutchpakcs, and how fast fixed-spring-rate springs can release clutches) and trying to make it happen as fast as possible without a tie up shows just how amazing the brain inside that little gray box it.

So now that you know how an allison works, you can see the need for that split second "empty" time between shifts. The faster the shift time (handoff between clutchpacks) is, the greater the possibility of a tie up because of unknown variables (fluid temp, how fast it can fill a clutch). The TCM has to make the shift as fast as possible without risking a tie up situation.

During that shift handoff, there is a split second amount of time than the transmission is in "no" gear. It is normally around ~300ms or so. That dead time is when the handoff has to happen. I you apply full power through the shift, you are going to get a HUGE "flare" because for that ~300ms the engine is not going to be under any load. If you dont have defuel, the engine will zing up (rpm's) and so when the next gear "comes on" the turbine speed (input speed)will be a LOT higher than expected and what happends is you smoke the clutches. Think of doing a 7000rpm clutch drop on a manual car. You need to use the clutch when you are full throttle shifting a manual car right? Same thing with an allison. The defuel is mandatory to get smooth shifts around town and not get flared, burning clutches under WOT with big power.

With the dodge transmissions, there are overrrunning clutches so you can theoretically make the shift time 0ms, and the shift will happen as fast as mechanically possible without worry of a tie up or anything. You can have a full power shift in a dodge trans because there is no "down time" (neutral) between gears. You go directly from one gear to the other.

So before you think of the allison as "wow what a POS trans, it cant even shif under full power, how pathetic that it needs a defuel to live", read my explaination above and hopefully it will give you a better understanding of the latest auto trans technology and how incredibly different it is from 40 year old auto technology (48re), and why common thoughts and theories from old automatics can NOT be applied to the allison simply because it functions like no other auto out there and has different "needs" (defuel) than other auto's.

Im not dumping on the 48re or anything, Im just trying to inform you guys before you go unfairly dumping on the allison for something that is key to making it even work. Its like making fun of a professional athlete for drinking lots of water every 2 minutes. WELL JEEZ!! Ive gone for hours without drinking water, what is wrong with those silly athlete people???

In built form with STOCK HARD PART internals, an allison will BY FAR outlive a 48re or torqshift. Same reason a cummins will outlive any of the other diesels on stock internals. They are just so much bigger and desined for more heavy duty use.

95% of allison hard part failures are NOT from a simple overpowering of the trans and pushing shafts to their shearing point. Most failures are from "tie ups", be it from allison aftermarket technology that is flawed (DTT, offence to them, they make a killer dodge trans, but they have not had great suiccess with the allison), engine tunes that have no defuel, and other random unexpected, unaccounted for glitches (air bubble in fluid cause a delay in clutch apply)....

take it for what its worth, but I my transmission is the LEAST of my worries on my truck under big power. Just like the cummins is the least of your guys' worries.

ben

duratothemax

They deserve 100% all of the credit and hype they get. For all the "stock allison failures", I bet 99% of them are from idiot dealer techs who dont knw how to diagnose an NSBU failure. How could you possibly discredit something for not being able to do something it wasnt designed to do??!?

If you leave the engine stock, change the allison spin-on filter reguarly, the trans will easilly last 500,000 miles. (sweet, here is where I get the "well my mothers uncles sisters mailman went through 3 allisons in 40,000 miles and his truck is stock!!!) Up the power and you will limp it in no time. Whos fault is that? YOURS. You play, you pay.

We (dmax people, I will personally never discredit the cummins. I dont like dodge trucks at all, but I would be a fool to say the cummins is a POS as well) generally dont pick on the cummins and give you guys the credit it deserves. Yet we cant even get any credit in return for our little piece of "medium duty" on our trucks?

Hdmax

I would have to say that the Allison is to transmissions as the Cummins is to Diesel engines. Neither is bullet proof 100% of the time. The Allison is a great auto transmission.

dodgezilla04

Will, what tranny can you get in the 550 ans 650 trucks with the CTD? that may be easier to mate into the project vehicle.