Concerns with 6 speed transmission vs 10 speed transmission?

Ray Pickle · October 23, 2021

Arbitrary need for 10 speed? Logic? Clearly not.

kylant · October 25, 2021

On 10/23/2021 at 6:43 AM, CRApex said:

With that logic just keep it simple and go back to a 4spd..lol.

Sorry, I'll stick with my statement...until they offer a 10spd, I won't consider the gas truck..and even then I still might prefer the diesel but atleast it will make me think about it.

why?

although the 10 speed in my truck is smooth, it seems like it is always shifting

sheath · October 25, 2021

Light, inexpensive and bullet proof make the 6 speed hard to pass up.

Rather keep the price of the truck lower, and the weight down.

CRApex · October 26, 2021

22 hours ago, kylant said:

why?

although the 10 speed in my truck is smooth, it seems like it is always shifting

We have two 2020 HD 2500 gas trucks that I drive from time to time to time. My personal truck is a 3500HD with the diesel and 10spd. The diesel drives soo much better with the 10spd towing or empty. I know its not really a fair comparison but given my personal preference and experience, the gas truck would need at least a 10spd to get me to consider it and like I said, that might not do it either. To each his own I guess, if you like the gas truck and 6spd, that's great, it's a solid setup.

Stand By · October 29, 2021

Unless they are putting a granny gear in the 10 speed, I don't see the need. Just more parts and heat and friction with more shifting. Rarely doe the current truck need to downshift for hills when empty and cruise control set (hardly ever). Holds the gear pretty well when towing,too. A diesel has a different power band than a gas engine. I'd be interested to see a towing comparison while accelerating. Seems like a 6 speed would allow for a longer power band, keeping the rpms up longer, making better use of the power? Obviously a diesel reaches full power sooner, requiring an upshift.

CRApex · October 29, 2021

12 hours ago, Stand By said:

Unless they are putting a granny gear in the 10 speed, I don't see the need. Just more parts and heat and friction with more shifting. Rarely doe the current truck need to downshift for hills when empty and cruise control set (hardly ever). Holds the gear pretty well when towing,too. A diesel has a different power band than a gas engine. I'd be interested to see a towing comparison while accelerating. Seems like a 6 speed would allow for a longer power band, keeping the rpms up longer, making better use of the power? Obviously a diesel reaches full power sooner, requiring an upshift.

It will be interesting to see the difference once the 10spd is being used in the gas HD. Also, the reviews will be fun to compare to this thread and see how the gas/10spd combo is received.

Ray Pickle · October 29, 2021

Lower 1st gear multiplication will be a plus and possibly better unloaded cruising economy. It will not be a significant step up overall.

topdj · January 1, 2022

On 9/22/2021 at 1:20 PM, Ray Pickle said:

Lowest warranty transmission over time has been the 6 speed in h.d. trucks I would assume that will continue based on additional enhancements made in 2020 additional clutches etc.

I couldn't find any info on the upgrades on 2020 six speed. My 2011 hd transmission has been great. I plow with it and tow. What upgrades did they do?

sheath · January 2, 2022

On 1/1/2022 at 8:43 AM, topdj said:

I couldn't find any info on the upgrades on 2020 six speed. My 2011 hd transmission has been great. I plow with it and tow. What upgrades did they do?

I'm interested in this as well. I've been a fan of this series of transmissions. I didn't realize all the updates that have been made over it's production run.

Here are historic updates. Guessing this pdf is from before 2020.

https://atracom.blob.core.windows.net/webinars/gm/6l50_80_90_updates.pdf

mrjulian416 · January 3, 2022

On 1/1/2022 at 11:43 AM, topdj said:

I couldn't find any info on the upgrades on 2020 six speed. My 2011 hd transmission has been great. I plow with it and tow. What upgrades did they do?

Go to 3:28 in this video. The lead engineer explains the changes. Basically they added one set of clutch and backing plates, and the torque converter is a "new design" using existing components. I read somewhere that the converter is slightly stronger/higher capacity than the '19/earlier design. All other stuff is the same.

GM 6 Speed Engineer explains

Edited January 3, 2022 by mrjulian416
fixed link

sheath · January 3, 2022

1 hour ago, mrjulian416 said:

Go to 3:28 in this video. The lead engineer explains the changes. Basically they added one set of clutch and backing plates, and the torque converter is a "new design" using existing components. I read somewhere that the converter is slightly stronger/higher capacity than the '19/earlier design. All other stuff is the same.

GM 6 Speed Engineer explains

Thank you Sir!

I had watched this video about a year ago, and totally forgot about the transmission section.

Really appreciate you posting this up! :cheers:

L8T · January 16, 2022

I drive a 7.3 F-550 with a 10 speed every day at work. Granted it’s a heavy service truck with lower rear gear ratio than my 3500HD gas but it drives so much better. I absolutely hate the 6 speed in this gas truck. It wouldn’t be so bad if I could tune it like I could the 6 speed diesels because there is a lot left on the table for driveability, but seeing as nobody wants to bother cracking the gm ecm the only choice is to hope for more gears.

Personally I don’t mind the truck I have but I will wait for either tuning to come available or more gears in a newer truck and after driving this one would recommend others do the same.

the wanderer · January 17, 2022

One obvious benefit of a 10 speed is fuel efficiency. Willing to bet it takes off much easier from a stop as well under heavy load. It's like going from a 3.73 to 4.30 when accelerating from a dead stop; but when on the highway you also get to keep your 3.73 for fuel efficiency. Best of both worlds.

10 gears is reaching diminishing returns, no doubt, but it's almost double the gear count of the 6 speed and I'm sure the difference in drivability will be huge.

Not saying you guys with the 6 speed should be unhappy, but there is room for improvement as well.

And "always shifting" is not a hard and fast rule, that's a result of transmission tuning, not a result of simply having 10 gears.

KARNUT · January 17, 2022

Just now, the wanderer said:

One obvious benefit of a 10 speed is fuel efficiency. Willing to bet it takes off much easier from a stop as well under heavy load. It's like going from a 3.73 to 4.30 when accelerating from a dead stop; but when on the highway you also get to keep your 3.73 for fuel efficiency. Best of both worlds.

10 gears is reaching diminishing returns, no doubt, but it's almost double the gear count of the 6 speed and I'm sure the difference in drivability will be huge.

Not saying you guys with the 6 speed should be unhappy, but there is room for improvement as well.

And "always shifting" is not a hard and fast rule, that's a result of transmission tuning, not a result of simply having 10 gears.

Most everything for the good of fuel mileage is very expensive to rebuild or repair. More than eliminating any fuel savings. Even buying extended warranty for protection cuts deep into any fuel savings. As far as performance. How often does anyone really put the hammer down. I understand completely though. I was 60 before performance wasn’t my top priority. Now it’s comfort then performance in that order. As far as fuel mileage that was never a top priority. 3-5 MPGs different isn’t going to break anyone. Rebuilding a ten speed or cylinder deactivation that could hurt.

the wanderer · January 17, 2022

4 minutes ago, KARNUT said:

Most everything for the good of fuel mileage is very expensive to rebuild or repair. More than eliminating any fuel savings. Even buying extended warranty for protection cuts deep into any fuel savings. As far as performance. How often does anyone really put the hammer down. I understand completely though. I was 60 before performance wasn’t my top priority. Now it’s comfort then performance in that order. As far as fuel mileage that was never a top priority. 3-5 MPGs different isn’t going to break anyone. Rebuilding a ten speed or cylinder deactivation that could hurt.

I don't think it's a given that 10 speed is naturally going to fail quicker than 6 speed just because it has more gears. Look at the ZF 8 speed, it's legendary and bullet proof, used in exotic sports cars, lots of Jeeps, the Ram's as well. We (us ram guys) all know it's far more reliable, and far more buttery smooth than anything FCA has ever put out.

So I think it's more about design, tuning, and manufacturing than simply "high gear count = worse reliability than low gear count".

Speaking of comfort, a 10 speed might mean you can cruise at 2200 RPMs instead of 2900 (or whatever). Basically, you have more ability to find that optimum RPM where it is making enough power but not revving higher than it needs to. That definitely adds comfort to your ride on long hauls.