Not much talked about here on the new GM 6.6 engine. Whats the thoughts from people that own one? I may be interested in getting one next year if it has the 10 speed transmission. Wish there was a bit more published testing other than those two guys that don't seem to really know what they're doing. Please don't refer to them since the test they did mentioned that the truck was floored and it showed the RPMs at like 3600 or what ever it was. But any real life input would be appreciated.

Not experience but opinion. I wouldn’t spend $5 on the last place engine for power combined with the oldest transmission. That is unless I wasn’t planning on really towing anywhere near it’s capacity. GM gasser trucks are like Ram diesels. Once they get with the program transmission wise, they’ll be viable imo.

I don't have one, but have been looking at them.I would not expect a 10 speed until 2022 at the earliest. This is my biggest disappointment and one reason I may end up with Ford and the 7.3L.I know the GM factories had a strike early in the year and then Covid hit, so dealerships where I am don't even have the **** things to look at or test. And they have stopped taking 2020 orders and are not taking 2021 orders yet. Applies to both Ford and GM.

I just picked one up about 2 weeks ago. Double Cab loaded up LT.While I do wish it had an 8 or 10 speed, the 6 doesn't seem to do a bad job. And historically the 6L90 has been a pretty reliable tranny.I have only towed with it 1 time. My fiver is about 9600lbs ready to camp. It did a good job by my expectations. It's not a diesel, which have had in the past, and didn't want to go that route. RPM's towing run from 2k up to pushing 4k in the hills. This is expected with a normally aspirated V8. Got about 9mpg according to the meter. Power was good at that weight. I don't think I'd want to tow the 17k it is rated for though.Under normal driving it's showing about 15mpg. I haven't checked it since I'm still one the first tank. I don't expect it to get much better.

No question, I really like the looks of the Silverado and the 6.6 has impressive numbers but unfortunately I need a truck prompto so felt Ford pulled ahead with the 7.3 10spd auto especially for my needs, a designated tow vehicle. I've owned 5 Chevy trucks and been very pleased and see quite a few 2020's locally including 2 retired friends of mine who really like their 6.6 trucks. GM needs to catch up in the tranny department.

I like mine, i would have liked the 10 speed trans better but the 6 speed is not as bad as i thought it would be. My TT is light though. For me its a world of difference from my 2012 1500 GMC sierra. Gas millage is a bit better, truck is bigger , mirrors and back up camra to hook up the TT are good. Seats not as conformable. But ok for a longer drive. The power is very noticable. I can pass trucks , cars at will now. Before i was at everyone elses will, lol. Its a nice truck, and i didnt want or need the diesel. I think i got a decent dwal during the covid, before people were looking at buying stuff. So for me it was a win. Tow mirrors are excellent, more cab room for bigger people, this can be a negative if you are short. Bigger bed, so you can take more stuff with you. Ask away, i will try to answer best i can. I had it on 5 trips so far this year. All about 3 to 6 hours away. Oh, giant fuel tank. So the same if not a little better on mpg but the tank makes for half the fuel stops. Wish i had that last year , i did nj to disney world.

GM 6.6 gas | Good Sam Community

Groover
Explorer II
Sep 18, 2020
colliehauler wrote:
Krusty wrote:
Ford's 10R80 transmission was a joint venture between Ford and GM. It is a light duty transmission used in vehicles like the F150 and Mustang. It is not an HD transmission that would be suitable in the HD trucks.
Thanks for the clarification.

I suspect that the 10R140 used in Super Duty trucks is closely related to the 10R80, just scaled up for the extra torque. I don't understand why GM took so long to do the same thing.
colliehauler
Explorer III
Sep 18, 2020
Krusty wrote:
Ford's 10R80 transmission was a joint venture between Ford and GM. It is a light duty transmission used in vehicles like the F150 and Mustang. It is not an HD transmission that would be suitable in the HD trucks.
Thanks for the clarification.
lly-zf6
Explorer
Sep 17, 2020
trailrider wrote:
Dadoffourgirls wrote:
Must be there are only 3 RVers that own a 6.6 gas engine, based on the responses. Must be many that go for the Duramax.

That is the result of dealers only ordering diesels to put on the lot. It is almost impossible to find a gas powered HD pickup sitting on a lot. Unless you want a white work truck.

There is some truth to that statement.
I just bought mine a few weeks ago.
My dealer ran a 250 mile radius trace for a LT double cab gasser.
There was a total of 1 on the lots.
trailrider
Explorer
Sep 17, 2020
Dadoffourgirls wrote:
Must be there are only 3 RVers that own a 6.6 gas engine, based on the responses. Must be many that go for the Duramax.

That is the result of dealers only ordering diesels to put on the lot. It is almost impossible to find a gas powered HD pickup sitting on a lot. Unless you want a white work truck.
Krusty
Nomad II
Sep 16, 2020
Ford's 10R80 transmission was a joint venture between Ford and GM. It is a light duty transmission used in vehicles like the F150 and Mustang. It is not an HD transmission that would be suitable in the HD trucks.
Dadoffourgirls
Explorer
Sep 16, 2020
Must be there are only 3 RVers that own a 6.6 gas engine, based on the responses. Must be many that go for the Duramax.
Grit_dog
Navigator
Sep 15, 2020
noteven wrote:
Grit dog wrote:
noteven wrote:
Is there something wrong with the Allison transmission in GM pickups?

Other than it doesn't have 4 overdrive speeds mostly useless for towing?

Other than the gasser trucks haven’t had the Allison option since the 8.1L days, nothing is wrong with the Allison.

GM calls Allison: "We need more speeds... consumers want speeds!"

Allison: "Why?"

GM: "Because Ford has more speeds..."

Allison: "But Ford uses 140 cubic inch engines..."

Too many Molsons?
You’re not making sense son...
Groover
Explorer II
Sep 15, 2020
noteven wrote:
Grit dog wrote:
noteven wrote:
Is there something wrong with the Allison transmission in GM pickups?

Other than it doesn't have 4 overdrive speeds mostly useless for towing?

Other than the gasser trucks haven’t had the Allison option since the 8.1L days, nothing is wrong with the Allison.

GM calls Allison: "We need more speeds... consumers want speeds!"

Allison: "Why?"

GM: "Because Ford has more speeds..."

Allison: "But Ford uses 140 cubic inch engines..."

Allison does not build transmissions for GM. GM licensed the name for marketing reasons.

I have an actual Allison 6 speed in my motorhome. I really wish that it had one or two more gears. You do not notice the gear spacing much when lightly loaded but as you allude to it is much more important when heavily loaded. Most people buying a 3/4 ton or up expect to load it heavily at times. My motorhome is always heavy.
cptqueeg
Explorer II
Sep 15, 2020
gmckenzie wrote:
I don't have one, but have been looking at them.

I would not expect a 10 speed until 2022 at the earliest. This is my biggest disappointment and one reason I may end up with Ford and the 7.3L.

I know the GM factories had a strike early in the year and then Covid hit, so dealerships where I am don't even have the **** things to look at or test. And they have stopped taking 2020 orders and are not taking 2021 orders yet. Applies to both Ford and GM.

My Chev dealer was ready to take an order for a 2021 HD a month ago.
noteven
Explorer III
Sep 15, 2020
Grit dog wrote:
noteven wrote:
Is there something wrong with the Allison transmission in GM pickups?

Other than it doesn't have 4 overdrive speeds mostly useless for towing?

Other than the gasser trucks haven’t had the Allison option since the 8.1L days, nothing is wrong with the Allison.

GM calls Allison: "We need more speeds... consumers want speeds!"

Allison: "Why?"

GM: "Because Ford has more speeds..."

Allison: "But Ford uses 140 cubic inch engines..."