The Mystery that is the 68RFE

USARMY12V

USARMY12V

Rally round the Virginian
Joined
Jan 17, 2012
Messages
711
Moving from the 47RE in my 98 to the 68RFE in my 2010 has been an upgrade and downgrade all at the same time. Due to having more forward gears, the 68 obviously provides better economy due to having more ratios, but outside of that it seems like the 68 is a piece of crap compared to its 47/48 brethren. The certainty offered by the old school trans is non-existent in the new ones which seems to search for gears based off of the input of the driver and also the terrain you're driving upon.

Mind you I am currently deployed so I haven't gotten a chance to swap from MCC from Dave at Draconian to his EFI Live that I do have sitting at home waiting on me. But, that being said, I am looking at my options going forward with the truck and am not opposed to a 48 swap but there seems to be more and more success stories of 68's as time goes no but I am not sold nonetheless. People over on the CF reportedly running add a turbo kits for several thousand miles with no complaints, running 7x'mm turbo's and no issues, etc. Then you have the horror stories of people adding a tuner and smoking their trans on their first joy-ride out (most of this due to them and the trans shift logic not being knowledgeable of the new tuning granted)

Is there something I have missed while I have been gone overseas? Is the tuner made trans tuning really THAT big of an upgrade from the MCC/Overdrive days? Is it worth it putting a VB and TC in my truck or would I be money ahead to just do a 48 swap even though it is super intensive in so much that it requires driveshaft modification. I like how the tow/haul, exhaust brake, and transmission all work together in tandem and it would suck to lose, but if I do a second gen swap it already takes away part of that combo anyways so prolonging transmission life is more important to me. I just don't want to waste money on the 68 if it's a lost cause in the end nor do I want to swap if these things have somehow taken a gigantic leap forward.
 
I won't be home for several more months so it's going to be quite awhile haha. Just trying to get a game plan going.
 
Keep reading searching Maybe in a few months there will be more info! This is a fast moving upgrade issue but it is 2 or 3x as expensive than a reliable 48RE.
 
I will add that my '11 currently has 135k on it. About 90k of those miles are deleted with a mini max with trans tune. I have no complaints from my 68RFE as I pull 15-20k with it weekly plus daily driving. Don't get me wrong I love to hammer on it and feel the power but I also believe it all goes back to how much self control and how well you take care of it.
 
And from what little info there is on the trans tuning done by tuners, it seems like it is an improvement over H&S OD as well... I would say 90% of the time the transmission is "doing the right thing" but there's certain scenario's that make the transmission act like it has no idea what's going on. The biggest gripe seems to be when you're accelerating at about 40 mph when it want's to upshift but then you let out so it therefore downshifts and it goes in and out of lockup obnoxiously. Also whine in overdrive under heavy load. I haven't personally had any issues with mine thus far but I'm on the fence whether or not I should get a VB and TC or perhaps hold off because the inevitable will happen.
 
I have yet to have any symptoms to make me dislike this transmission. Far better than any performance 47/48 transmission that shifts so hard.
 
Do a 3D TC, billet input, 1st gear sprag upgrade, shift kit, H&S Overdrive and it will be night and day difference. MCC custom trans tunes are nice cause they are tailored to your likes.
A couple companies like Suncoast and Revmax have billet overdrive drums that are made to be able to hold more OD clutches. Thats a nice upgrade to since thats a weak link in the 68 but the right trans tune will keep you in the lower gears (1-4) to be able to handle the power/torque.

I ran a Suncoast Comp68 with H&S OD and I never had any issues. FYI have never seen a broken intermediate or output shaft so no one make a billet version of those two yet.
 
Kronk said:
Do a 3D TC, billet input, 1st gear sprag upgrade, shift kit, H&S Overdrive and it will be night and day difference. MCC custom trans tunes are nice cause they are tailored to your likes.
A couple companies like Suncoast and Revmax have billet overdrive drums that are made to be able to hold more OD clutches. Thats a nice upgrade to since thats a weak link in the 68 but the right trans tune will keep you in the lower gears (1-4) to be able to handle the power/torque.

I ran a Suncoast Comp68 with H&S OD and I never had any issues. FYI have never seen a broken intermediate or output shaft so no one make a billet version of those two yet.
Click to expand...

Didn't RJP twist one of those shafts awhile back?

Also to the OP the 68 is a great trans and there has been a lot of progress made over the year with it. The best advice you can have though is H&S trans tuning like others have said. This is actually the recommended tuning for the comp68 from suncoast aswell and has great tuning options for anyone.

The 3-4 shift is a weak spot in a factory trans, the overdrive cruise to a hard downshift for heavy acceleration will weld clutches fast, but most of all the TCM it's self is essentially the ugly step child to the 6.7 ecm and since the TCM is constantly adapting to your driving patterns it can make the 68 feel different from day to day with different driving.
 
blackmega3500 said:
Didn't RJP twist one of those shafts awhile back?

Also to the OP the 68 is a great trans and there has been a lot of progress made over the year with it. The best advice you can have though is H&S trans tuning like others have said. This is actually the recommended tuning for the comp68 from suncoast aswell and has great tuning options for anyone.

The 3-4 shift is a weak spot in a factory trans, the overdrive cruise to a hard downshift for heavy acceleration will weld clutches fast, but most of all the TCM it's self is essentially the ugly step child to the 6.7 ecm and since the TCM is constantly adapting to your driving patterns it can make the 68 feel different from day to day with different driving.
Click to expand...

More on these improvements in the last year?

Is it all tuning because I haven't seen anymore hard parts hitting the market.
If good tuning alone could handle ~550rwhp with a 68rfe, I'd probably have a 4th gen by now. I just have it in my head that a 4th gen costs $12k more than what you buy it for so you can get a 48re behind it.
 
I've heard Commercial Powertrain out of Alberta is putting pretty good power through them without issues.
 
I have heard good things about Commercial Powertrain as well. However, I don't believe he warranties transmissions he doesn't install himself and thus a huge problem for us Americans.

The conveniences these transmissions offer is great, however the overdrive issues and weird torque converter processes makes you lose faith in the transmission. Regular driving it is a dream, but when you start giving it some fuel things aren't so assured anymore. And nothing ruins your will to use the go-pedal like questioning if you're going to have to buy an $8000 transmission due to one second of fun on the streets that you didn't have to worry about with a 47/48 beforehand. I realize you gotta pay to play, we all know that. But it seems like even paying for these things is a crapshoot at best.
 
USARMY12V said:
I have heard good things about Commercial Powertrain as well. However, I don't believe he warranties transmissions he doesn't install himself and thus a huge problem for us Americans.

The conveniences these transmissions offer is great, however the overdrive issues and weird torque converter processes makes you lose faith in the transmission. Regular driving it is a dream, but when you start giving it some fuel things aren't so assured anymore. And nothing ruins your will to use the go-pedal like questioning if you're going to have to buy an $8000 transmission due to one second of fun on the streets that you didn't have to worry about with a 47/48 beforehand. I realize you gotta pay to play, we all know that. But it seems like even paying for these things is a crapshoot at best.
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I don't believe anybody other than himself installs his 68rfe's.


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I will also add that Steve has been talking with an outfit in Texas about possibly in the future partnering with him to do the installs for the customers here in the states. But I believe it's all fuel by interest of those of us here.


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USARMY12V said:
Moving from the 47RE in my 98 to the 68RFE in my 2010 has been an upgrade and downgrade all at the same time. Due to having more forward gears, the 68 obviously provides better economy due to having more ratios, but outside of that it seems like the 68 is a piece of crap compared to its 47/48 brethren. The certainty offered by the old school trans is non-existent in the new ones which seems to search for gears based off of the input of the driver and also the terrain you're driving upon.

Mind you I am currently deployed so I haven't gotten a chance to swap from MCC from Dave at Draconian to his EFI Live that I do have sitting at home waiting on me. But, that being said, I am looking at my options going forward with the truck and am not opposed to a 48 swap but there seems to be more and more success stories of 68's as time goes no but I am not sold nonetheless. People over on the CF reportedly running add a turbo kits for several thousand miles with no complaints, running 7x'mm turbo's and no issues, etc. Then you have the horror stories of people adding a tuner and smoking their trans on their first joy-ride out (most of this due to them and the trans shift logic not being knowledgeable of the new tuning granted)

Is there something I have missed while I have been gone overseas? Is the tuner made trans tuning really THAT big of an upgrade from the MCC/Overdrive days? Is it worth it putting a VB and TC in my truck or would I be money ahead to just do a 48 swap even though it is super intensive in so much that it requires driveshaft modification. I like how the tow/haul, exhaust brake, and transmission all work together in tandem and it would suck to lose, but if I do a second gen swap it already takes away part of that combo anyways so prolonging transmission life is more important to me. I just don't want to waste money on the 68 if it's a lost cause in the end nor do I want to swap if these things have somehow taken a gigantic leap forward.
Click to expand...


First you need to determine how much power you plan on making before anyone can give the best advice based on personal experiences? What gear ratio and tire size do you run or plan on running?
 
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Freezingsystems said:
First you need to determine how much power you plan on making before anyone can give the best advice based on personal experiences? What gear ratio and tire size do you run or plan on running?
Click to expand...
My power goals are never pinned down because with these new trucks the transmission is hit or miss as we are seeing. There's people with add-a-turbo's who push 7-800 with a stock transmission yet people who simply delete and tune then blow it first time around the block. I currently have 3.73's and 35's. I would never go larger tire than that so gear ratio isn't really an issue for me like guys with 37's or larger... I'm the only one who drives the truck minus my buddy who is currently taking care of it while I'm overseas but obviously that would change once I get back to just me again. I would love to do a second gen swap but I would prefer to sort out the trans first.
 
USARMY12V said:
My power goals are never pinned down because with these new trucks the transmission is hit or miss as we are seeing. There's people with add-a-turbo's who push 7-800 with a stock transmission yet people who simply delete and tune then blow it first time around the block. I currently have 3.73's and 35's. I would never go larger tire than that so gear ratio isn't really an issue for me like guys with 37's or larger... I'm the only one who drives the truck minus my buddy who is currently taking care of it while I'm overseas but obviously that would change once I get back to just me again. I would love to do a second gen swap but I would prefer to sort out the trans first.
Click to expand...


Whose driving an add a turbo truck at 7-800 HP on a stock 68rfe? That's simply not gonna happen.

Just talk with suncoast or Steve at commercial powertrain and get a replacement unit. That's really the only solution.


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My opinion of the 68rfe is there are just so many points of failure that can happen in them. I am a believer in the trans tuning really helping or being the hope of extended life. How long a tranny is going to last is going to be based on horse power, tire size and gear ratio, and mainly how the truck is driven. If driven hard I have seen lots of failures of toasted OD/UD clutches. That includes 68rfe omega drums as well and not at nearly the power they are "rated" for.

My stock trans was pulled out at 130k miles due to just starting to slip in the higher gears but nothing was toasted yet. The truck was deleted from 60k-100k with just h&s tuning and their tuning, from 100k to 130k it has add a twin kit, 60% nozzles, cp3 and tuning. Truck has 35" and 3.73 gear ratio. Truck was drove hard and also worked but never really abused or raced. Since building the trans with a revmax 550 kit with a billet input also, I have been pushing the truck much harder and so far all seems to be well. Have about 10k miles on it since then so time will tell.
 
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