Looking for input on G56 vs. Aisin

[TX Diesel]

I'm about to order a Tradesman 3500 SRW that will be used for a mix of unloaded daily driving (80%) and pulling a 40ft flatbed GN trailer (20%), often loaded to max trailer weight rating. The truck will not be raced or hotrodded. All 3 of my previous Cummins-equipped trucks have remained stock without a tune, so I don't foresee adding one to this truck.

While I'm willing to fork out $2700 for the Aisin, my nostalgic side says to get the G56 before Ram quits offering it. I know it's detuned and anything over stock power levels causes issues with the clutch, but are there other practical reasons to get the Aisin over the manual? Here are my thoughts about one vs. the other so far.

Performance:
I don't have any concerns about performance with the detuned 660lb/ft. of the engine with the G56. I had a 1999 2500 with the Cummins and 5-speed NV4500 and with 460 lb/ft. it pulled the same trailer load without any issues, so 660 should be fine. With the Aisin the engine has the higher torque rating, but (1) I believe it's torque limited in the lower gears and (2) there's always some drivetrain loss through automatics so the actual performance level between the two may be closer than many think. Has anyone used them back to back in a pulling scenario? Any input on how much of a difference there really is?

Resale:
I plan on keeping the truck until the wheels fall off so resale isn't critical to me. If for some reason that changes the G56 may hurt resale, but then again since it's hard to find one it may actually help it for those that really want one and can't find one. I would assume the Aisin would likely help resale, but likely not enough to overcome the initial $2700 upcharge.

Longevity:
I can replace a clutch myself, and the cost would likely be minimal unless I decided to go to a single mass flywheel, dual disc clutch, etc. All of my previous manual trans trucks have gone at least 150k miles on the original clutch. Assuming there are no issues with the stock clutch at stock power levels, I'd like just go back with the stock arrangement. With the Aisin though, I'd be looking at a rather hefty bill (at least $5k?) when it comes time to rebuild it. I'm religious about maintenance, so I'd hopefully get 250-300k miles out of the original one though.

 

[Cummins12V98]

The AISIN has a STELLAR record! spend the money and enjoy! Also enjoy the much better resale.

 

[Newsa]

I doubt you will ever have to rebuild the Aisin.

But, I hear the Aisin needs to be serviced every 30,000 miles. That would be a no-go for me. And it's not cheap if you use synthetic and replace the filter.

I have the g56 and it is adequate.

All three trannies are good. Go with what you want.

 

[SnoKing]

Get the Aisin and 3.42 gears. You will really enjoy those 80% miles, and it will do just fine for the 20% towing of the 1999 towed the loaded trailer.

 

[Doubleclutch]

Well, with the 6 Spd G56, you could always consider the transmission as a Millennial theft prevention device...

 

[SnoKing]

Well, with the 6 Spd G56, you could always consider the transmission as a Millennial theft prevention device...

Ain't that the truth. Or you would get it back with both the clutch and transmission trashed.

 

[Newsa]

Ain't that the truth. Or you would get it back with both the clutch and transmission trashed.

I like the stick shift transfer case that comes with the g56.

Diesel hub has some good info.

Here's a link.

Says that the Aisin is very efficient unloaded.

http://www.dieselhub.com/compare/aisin-vs-68rfe.html

Here is g56

http://www.dieselhub.com/trans/g56.html

 

[TX Diesel]

Thanks for the input. I spent a lot of time here from 96 to 2006 due to my previous trucks but can't find my login info so I had to re-register. I've always been impressed with the amount of knowledge and assistance TDR provides.

I doubt you will ever have to rebuild the Aisin.

But, I hear the Aisin needs to be serviced every 30,000 miles. That would be a no-go for me. And it's not cheap if you use synthetic and replace the filter.

I have the g56 and it is adequate.

All three trannies are good. Go with what you want.

Newsa: when you say the G56 is adequate....does that mean there are some drawbacks with the trans itself, or that it's adequate with the detuned torque level? I've read about the potential need for the case girdle due to heat flex because the case is aluminum, but is that primarily for folks who tow for extended periods of time (5er, Hot Shot, etc)? During that 20% of the time it will be towing max trailer weight, but never more than 100-200 miles at a time so that may not be enough time to heat soak the case enough to cause it to flex.

Well, with the 6 Spd G56, you could always consider the transmission as a Millennial theft prevention device...

DC: No kidding. It is absolutely amazing to me how many folks in their 20's - even 30's - do a double take when they see a stick shift, much less know how to drive one. Back in 1986 I took my driving test in a flatbed Ford F350 with the 6.9 diesel and manual 4-speed and never thought anything about it. I was really glad to have the flatbed though - it sure made the parallel parking portion easy.

 

[TX Diesel]

I like the stick shift transfer case that comes with the g56.

Diesel hub has some good info.

Here's a link.

Says that the Aisin is very efficient unloaded.

http://www.dieselhub.com/compare/aisin-vs-68rfe.html

Here is g56

http://www.dieselhub.com/trans/g56.html

Thanks for the links. Completely agree on the T-case shifter. There's just something satisfying about feeling that 'clunk' when it moves into 4Hi or 4Low.

 

[Newsa]

Thanks for the input. I spent a lot of time here from 96 to 2006 due to my previous trucks but can't find my login info so I had to re-register. I've always been impressed with the amount of knowledge and assistance TDR provides.



Newsa: when you say the G56 is adequate....does that mean there are some drawbacks with the trans itself, or that it's adequate with the detuned torque level? I've read about the potential need for the case girdle due to heat flex because the case is aluminum, but is that primarily for folks who tow for extended periods of time (5er, Hot Shot, etc)? During that 20% of the time it will be towing max trailer weight, but never more than 100-200 miles at a time so that may not be enough time to heat soak the case enough to cause it to flex.



DC: No kidding. It is absolutely amazing to me how many folks in their 20's - even 30's - do a double take when they see a stick shift, much less know how to drive one. Back in 1986 I took my driving test in a flatbed Ford F350 with the 6.9 diesel and manual 4-speed and never thought anything about it. I was really glad to have the flatbed though - it sure made the parallel parking portion easy.

I don't tow much any more. But "truckmen" has a G56 equipped truck and pulls 3 and 4 cars all over the country. He might soom need to rebuild his. He runs his almost full time.

I put 5000 towing miles on mine. 500 of that is at it's max weight with a gooseneck. Andymac also does a lot of livestock hauling at many speeds on a mix of paved and dirt roads with the g56 and much of it in 4x4. You could message them to see their experience. Photowrite is a truck photo journalist who is also on Instagram. All of us love our manual trannies.

I doubt the girdle is necessary. I did put fast coolers on mine. And changed the fluid from OEM atf4+ to redline MTL.

 

[Tuesdak]

I also learned how to drive on a pickup with a manual transmission. I suggest you ask diffrent questions about the difference.

Grade braking: does the auto shut it down as well or does it still leave the torque converter unlocked? Maybe the auto is more durable , now, for this. In the past - just no...

Can you stand the constant push from the auto to move? It wasn't till I dropped a high stall converter behind something that this irratation went away esp. with a "lemon" design defect that wouldn't relibaly throttle the engine down on another ride of mine.

Auto's are sometimes in the wrong gear. I would like to lug the krap out of it unloaded at 35 mph in town , redline up a grade isn't always the best answer, or lugging it to death on lesser grades while ECT runs away... Control is a big difference. Automatic Over-ride buttons shift when the computer damn well feels like it.

Every time I shift the turbo winds down. An auto would out-run my 2003 NV5600. Traffic jams are a workout.

In town MPG is 1/3 better with a MT for me. This includes a 2005 and 2008 Duramax that got 10 MPG in town imo because it's too slow to lock the tcc up per GM. My dodge gets 16 mpg in the 35 MPH towns.

The biggest concern is if "dead pedal" applies to MT's or if it fixed for the autos.

 

[JR]

Go drive both if you haven't yet. There are lots of old school manual trans guys on here that are converts. The auto transmission has evolved ten fold from the gen 2 days. I myself was a gen 2 owner for 10+ years, I wouldn't own another one that wasn't a standard shift. But now that I'm in a 14 I can't say the same anymore.
Never experienced dead pedal but there is a significant amount of torque management on the bottom end. Annoying at first but I've gotten used to it. The power comes on, albeit more gently than years past. I suppose it's necessary when your pushing 800+lb feet through a light duty drivetrain.
EB in an auto locks the TC and works quite well. At the rate my brake pads are wearing they will see north of 200k miles, and I tow a good bit and load the bed heavy frequently. I've been impressed with the entire drivetrain on this truck - minus the complexity of the emissions.

 

[Regcabguy]

Well, with the 6 Spd G56, you could always consider the transmission as a Millennial theft prevention device...

When I frequent Discount Tire for tire service I always insist pulling it in.
I tell the management that the clutch is aggressive and that with improper engagement the truck will go through the building.
Get the Aisin.

 

[Cummins12V98]

Tow Haul and Exhaust Brake on, yes the trans downshifts!

 

[TX Diesel]

Can you stand the constant push from the auto to move? It wasn't till I dropped a high stall converter behind something that this irratation went away esp. with a "lemon" design defect that wouldn't relibaly throttle the engine down on another ride of mine.

We had a 2001 Cummins 2500 with the auto trans that always felt like it wanted to push through the stop sign/light when coming to a stop, so I would always shift to neutral whenever I came up on one. That got to be a pain after a while. Does the Aisin do the same?

Auto's are sometimes in the wrong gear. I would like to lug the krap out of it unloaded at 35 mph in town , redline up a grade isn't always the best answer, or lugging it to death on lesser grades while ECT runs away... Control is a big difference. Automatic Over-ride buttons shift when the computer damn well feels like it.

So the 'manual shift' buttons on the Aisin are limited by what the computer wants to do? I can understand limiting downshifts if the selected lower gear would over-rev the engine, but I like to 'short shift' in some cases and get up to a higher gear sooner....wondering if it would prevent that?

The biggest concern is if "dead pedal" applies to MT's or if it fixed for the autos.

Is the dead pedal an issue with all G56 trucks, or just some of them? I'm assuming it's part of the stock ECM tuning and acts as torque management? Or is it a defect only some trucks experience?

 

[Newsa]

Is the dead pedal an issue with all G56 trucks, or just some of them? I'm assuming it's part of the stock ECM tuning and acts as torque management? Or is it a defect only some trucks experience?

Torque management in the G56 trucks is governed by speed. There is a small amount of torque management up to 40-45 mph. But no dead pedal.

It goes from 55-70 faster than it goes from 30-45 because torque management is applied at lower speeds.

 

[Tuesdak]

@TX Diesel I have never driven a new Aisin. Just some questions I would ask if given the choice of MT or Auto. It's about control and how it may or may not act with the auto. End of the day what matters to you?

From what I read "Dead pedal" is specific to the Aisin. Said 08 Duramax of ours would have this to some extent as well if you had to abort a pass and then stomp the throttle - like the turbo was wide open and had to change position to spool back up.

When I hit a shift up/down button for most auto's there is an unpredictable delay that you simply can't "rev-match" and avoid the "bang" when the computer decides to shift. Real PIA when the ECM decides it isn't going to shift from the button presses.

My 2008 Duramax Allison would not use the top two overdrive gears at 35 MPH - you couldn't force it into a higher gear. Further it would lug the engine on some grades letting the ECT run away. One grade on our delivery route I would manually drop it out of double overdrive to keep the ECT from putting the "Numb" temp gauge 3/4 the way to the top. Cooling systems are a GM weakness made worse from oversights like this. Some grades are long enough require more RPM for the fan and water pump, but, not steep enough to trigger a shift from throttle input.

 

[JR]

With the auto trans, you are able to dictate down shifting and holding a lower gear if desired. It will not allow you to upshift as desired. It's really a non factor in my book. A few hundred rpm does not factor into a measurable difference in fuel mileage and it is every bit as beneficial to the engine as it is the trans to run a higher rpm, particularly under load .
I am a crane operator by trade among other things, I've run many SCR equipped 6.7 and 8.3 Cummins engines, the factory preset high idle while running hydros on a 6.7 is 2600 rpm. They don't think twice about running it all day long, either, and are more efficient than the old p pumped 5.9's and mechanical cat motors.

 

[lewkarg]

Just my $.02 on the G56. I've had my '18 for nearly three weeks now and have put 1550 miles on it since new (no towing yet). I'm a MT guy my whole life, and I hate driving automatics, which drove me to the RAM as the only manual diesel truck now. I've driven manual transmissions since my first car 15 years ago (and driver's test), but I have to say this is the most difficult clutch/transmission to drive. Both clutch pedal and shift throw are long, but this is to be expected and doesn't bother me. I had to deal with an issue with a noise/vibration in 6th gear, but the dealer took care of it under warrantee in 4 days (see my other thread a couple weeks ago). I seem to have a rough shift maybe 5% of the time. I usually notice it most in 2nd gear. Coming through 2,000-2,250 RPMs in 2nd for the upshift, when I depress the clutch, I occasionally get a violent shudder throughout the truck from power/drivetrain. Also, when coming to a stop from engine braking in 2nd, about 1,000-1,200 RPMs, I'll depress the clutch and get the same shudder. It's audible, and I can feel it in the clutch and throughout the truck. The shifts are smooth once I get into the next gear, but I'm still trying to figure out the little quirks in the clutch for smooth transitions.

Anyway, that's my feedback from almost three weeks of ownership. I can't comment on the Aisin since I've never driven one.

Let me know if you have any specific questions.

Edit: formatting and spelling.

 

[Newsa]

Coming through 2,000-2,250 RPMs in 2nd for the upshift, when I depress the clutch, I occasionally get a violent shudder throughout the truck from power/drivetrain. Also, when coming to a stop from engine braking in 2nd, about 1,000-1,200 RPMs, I'll depress the clutch and get the same shudder. It's audible, and I can feel it in the clutch and throughout the truck.

Yeah, I get a shudder when depressing the clutch at 2000+ rpm. But it doesn't seem abnormal to get a shudder with releasing a clutch at such high rpm. And likewise releasing the clutch at a low rpm (1000-1200).... It is normal to get a shudder. I get shudder, maybe a little noise but never thought it strange at high and low rpm.

If not towing, no reason to wind it up to 2000 rpm. If you are trying to jerk through gears in a fast take off, you can expect noise and shudder.