2015 auto or manual trans?

[cerberusiam]

Fuel us heavily de-rated under 12 psi of boost and 1800 rpms, inclusive. You can start the run as 15 psi and 1600 rpms and get approximately the same curve, fuel is almost 50% de-rated between from 1600-1800 rpms regardless of APPS or boost. Less fuel equals less power, TQ management. 5th gear in the auto is about the same as 6th gear in the G56 so it likely pretty close to the same curve. If he did the run as normal wheel speed was probably around 40-45 mph at the start, no slow wheel speed there just TQ management.

 

[gsbrockman]

5th gear in the auto is about the same as 6th gear in the G56

Correct........when I first saw the graph, I noted that the runs were done in 5th gear (.77) as well.

I've had past trucks on dynos before.......and they were all direct (1.00:1) when ran on the dyno (a 2003 RAM 2500 Quad Cab 4x4 305*555 w/NV5600--ran in 5th gear) and a 2007.5 RAM 3500 MegaCab SRW w/68RFE (4th gear).

What's your input on the AS69RC equipped truck being ran in 5th (.77:1)????

 

[cerberusiam]

What's your input on the AS69RC equipped truck being ran in 5th (.77:1)????

On an accelerometer dyno you have to run it in the highest gear available and lock it in to get close real world numbers. With 1:1 you get lower numbers because the dyno cannot load the engine hard enough to fully fuel. My guess is 5th gear can be locked in and 6th cannot so that is the gear they ran it in, should be fairly representative with OD ratio at that level. Would probably gain some in 6th but the numbers aren't as important as what is happening to the power curve, for a base line or changes.

 

[RVTRKN]

My C&C recorded 305 HP on a Dyno at May Madness in 2008, and is rated at 305 HP. I don't know if the C&C's are rated differently, but being completely stock I expected lower.

 

[Deleted member 995608]

The more i ponder between an auto and a manual, i think we just need to be grateful that a company is still giving us the two options to chose from. From there, we can chose whatever we want and I think that's bad*****

 

[photowrite]

The more i ponder between an auto and a manual, i think we just need to be grateful that a company is still giving us the two options to chose from. From there, we can chose whatever we want and I think that's bad*****

Amen to that; choice. It may not last that much longer, and when the sticks are gone, some of us will be sad.

 

[cerberusiam]

My C&C recorded 305 HP on a Dyno at May Madness in 2008, and is rated at 305 HP. I don't know if the C&C's are rated differently, but being completely stock I expected lower.

The actual number depends on whether the reading was SAE or corrected and the correction factor used. Could very well have a number at or above engine a published engine rating.

 

[kthaxton]

When it comes to transmissions, make your choice, then be a jerk about it.

 

[RustyJC]

On an accelerometer dyno you have to run it in the highest gear available and lock it in to get close real world numbers. With 1:1 you get lower numbers because the dyno cannot load the engine hard enough to fully fuel. My guess is 5th gear can be locked in and 6th cannot so that is the gear they ran it in, should be fairly representative with OD ratio at that level. Would probably gain some in 6th but the numbers aren't as important as what is happening to the power curve, for a base line or changes.

I ran my 2002 ETH/DEE 3500 (4.10 axle ratio) that was mildly bombed on a Dynojet inertial chassis dyno here in the Houston area. The truck was running an Edge EZ, DD Stage II injectors, a Jardine 4" exhaust and a BHAF. Since this was a Lone Star TDR dyno day event, there was a lot of discussion on this very point, so we made 6 passes on my truck, 3 in 5th gear (direct) and 3 in 6th gear. The 5th gear passes were in the mid 320s for HP, but the truck dynoed 347/762 (uncorrected) in 6th. As you say, the inertial dyno couldn't load the engine sufficiently in 5th to get the boost up as quickly and as high as it went in 6th. Since the fuel tracked the boost, more boost in 6th = more fuel = more power. One would surmise that the 4.10 axle worked against the dyno numbers as a 3.54 axle would have loaded the engine even more in 6th.

The standard dyno correction factors for altitude don't work with a turbocharged engine such as the Cummins. They are based on naturally aspirated engines that lose ~3% of their horsepower for every 1000 ft of elevation. The stock Cummins has turbocharger sizing that allows it to hold its sea level horsepower rating to 10,000 ft elevation, so a dyno reading corrected for altitude back to sea level will overstate the actual horsepower since it adds back in a horsepower loss that didn't occur.

Rusty

 

[Newsa]

When it comes to transmissions, make your choice, then be a jerk about it.

I realize i will not convert any Aisin owners/fans to G56. But have enjoyed being an *****h@/@ about it.
I enjoy this truck at all speeds. Even in stop & go traffic, it has perfect gears for crawling. Only thing i would change about the G56 is the aluminum case, reverse gearing, add a 7th gear overdrive, increase the oil sump and add fins or something for cooling. So yes. It isn't a perfect transmission. But all 3 offered transmissions have room for improvement.

 

[Newsa]

Amen to that; choice. It may not last that much longer, and when the sticks are gone, some of us will be sad.

When the sticks are gone, I won't buy any new ones.

 

[kthaxton]

I just wish all the claims (for and against) all the various transmissions were always based on fact, instead of the "I like mine, therefore yours sucks for these reasons (insert anecdotal evidence)" mentality, or, "my situation requires XXXXX transmission, therefore everyone's does".

 

[photowrite]

Snip... Only thing i would change about the G56 is the aluminum case, reverse gearing, add a 7th gear overdrive, increase the oil sump and add fins or something for cooling. So yes. It isn't a perfect transmission. But all 3 offered transmissions have room for improvement.

I'm assuming you would prefer a lower reverse ratio for backing trailers and such, me too. Wouldn't mind a lower first too, but that's less important. Of course differential gearing options would help here too, instead of 3.42:1 for everyone. Agreed, I've not owned a 'perfect' transmission yet.

Back In The Day I really liked how a granny box 4-speed drove (generic term for any non-synchro 4-speed w/ 1:1 4th), but I don't care to go back to having no overdrive, low power, carburetors, etc. For all the weaknesses tossed upon the G56 and its OE clutch ( I'm definitely not a DMF fan), there are plenty of examples of the gearbox giving good service. This includes a local buddy who pulled heavy often, and went well over 100k without issue, his wife has a G56 truck too.

Another transmission that ran hot, had an aluminum case and was not the most popular or respected was/is the ZF-S5 in my (sold) 1996 F-350. It needed a DMF replacement before 100k, but is still working well at 140k+, and it drove and still drives well (with Red Line MTL in the case).

Have to give a nod to Toyota's 5-speed A/T in my V8 4Runner, 3.52:1 first and 0.72:1 overdrive work well...and much better driving 4.88:1 gears.

Your mileage will vary.

 

[Newsa]

The G56 is really a pathetic excuse for a transmission in these trucks, opting for an auto is by far the better choice. Exactly oppositie of what it used to be but engine management and trans management has come a long way since the 47RE. For a multi-use truck and the ease of driving the auto cannot be beat.

I'd rather see anecdotal statements (if i hadn't already made up my mind) that i can learn from than this post. (See above)

But i realize that there are more Aisin fans on here than G56 owners. So i get ganged up on if i say i prefer the G56 to the Aisin. And when i remind Aisin owners of complaints about dead pedal and launch shudder. I've never driven an Aisin and never will.
Maybe when you pay almost $3000 for a transmission, you probably get a slightly better transmission. But i think the $ mark up on those Aisins is more than buying an Eaton or other high quality HD transmission. If i wanted an auto, i'd do my research. The original poster was asking for buying info. So of course you're going to get opinions and experience-related info.

 

[kthaxton]

I'm assuming you would prefer a lower reverse ratio for backing trailers and such, me too.

Hey, just realized that this is where the 68RFE shines, it has the lowest reverse ratio (4.44), y'alls other transmissions suck.

 

[RVTRKN]

Newsa, see my cooler posts and you have an answer to keeping it cool.

 

[Newsa]

I'm assuming you would prefer a lower reverse ratio for backing trailers and such, me too. Wouldn't mind a lower first too, but that's less important. Of course differential gearing options would help here too, instead of 3.42:1 for everyone. Agreed, I've not owned a 'perfect' transmission yet.

Back In The Day I really liked how a granny box 4-speed drove (generic term for any non-synchro 4-speed w/ 1:1 4th), but I don't care to go back to having no overdrive, low power, carburetors, etc. For all the weaknesses tossed upon the G56 and its OE clutch ( I'm definitely not a DMF fan), there are plenty of examples of the gearbox giving good service. This includes a local buddy who pulled heavy often, and went well over 100k without issue, his wife has a G56 truck too.

Another transmission that ran hot, had an aluminum case and was not the most popular or respected was/is the ZF-S5 in my (sold) 1996 F-350. It needed a DMF replacement before 100k, but is still working well at 140k+, and it drove and still drives well (with Red Line MTL in the case).

Have to give a nod to Toyota's 5-speed A/T in my V8 4Runner, 3.52:1 first and 0.72:1 overdrive work well...and much better driving 4.88:1 gears.

Your mileage will vary.

Yes, lower reverse ratio. I like the 3.42 for hwy mileage. I can always downshift to 5th when towing heavy up hills. RVTrckn has schooled me on the dangers of G56 overheating. And I'm glad I joined this forum to hear other's experiences. ...... Especially that the chassis fuel heater wasn't "turned on" at the factory.

I'm OK with gearing in first. But backing a large load into tight spaces would be easier with a lower reverse.

 

[Newsa]

Newsa, see my cooler posts and you have an answer to keeping it cool.

Planning on following up on this after my extended warrantee expires. I may have more questions. Thx!

 

[cerberusiam]

Only thing i would change about the G56 is the aluminum case, reverse gearing, add a 7th gear overdrive, increase the oil sump and add fins or something for cooling. So yes. It isn't a perfect transmission.

Basically, toss the transmission because it is inadequate in most if not all areas.

Has to be purely a philosophical thing to buy a truck with a manual that is an out and out fail, even by the proponent's estimation.

When there is a much better solution available this begs the next question, WHY????? :-laf

 

[mpaulson]

NEWSA,

I assume you have though of manual front hub for your truck? this would make for nice and easy two wheel low backing.