Will the GM 6T75 6 speed auto fit?

**Turbocharged400sbc** · 10-20-2015

keep in mind that the extra gears are there to keep an engine in its power band during acceleration to minimize emissions. modern engines don't produce the low rpm grunt that our engines do. so things like the extra gear down low and 2 overdrives you're going to find that you're rarely using certain gears or you end up with two shift points where you would normally have one. Now it would increase fuel economy and probably won't do what you think it will since the 3800 works so well on wide gear ratio spreads

**16MustangVet** · 10-20-2015

Agreed same reason GM is going to 8 and 10 speed transmissions for full size pickups and suv's

**BillBoost37** · 10-20-2015

Let's use my Audi as an example, it comes in at 300HP and 310TQ with a 6 speed. I have to be at a 100% full stop for it to use 1st again. It will also be in 6th by 40-45mph. Fuel mileage is well above advertised and yes.. the car is much faster based on always being in the power band.

I always felt that the SC 3800 had the torque to drop at least a 5th gear on for even better highway mileage.

**00Daytona** · 10-20-2015

Originally Posted by BillBoost37

Let's use my Audi as an example, it comes in at 300HP and 310TQ with a 6 speed. I have to be at a 100% full stop for it to use 1st again. It will also be in 6th by 40-45mph. Fuel mileage is well above advertised and yes.. the car is much faster based on always being in the power band.

I always felt that the SC 3800 had the torque to drop at least a 5th gear on for even better highway mileage.

I agree. at 80mph, with the car running right(currently is not) I was able to squeeze out 40mpg. As far as the car's DIC was concerned. That's at 2500rpm. If I was able to cruise around 1500rpm doing the same speed I would probably be able to get even better mileage. I drive about 90% highway, 10% around town.

BUT if I wanted a 6 speed w-body, that works correctly every day, id go buy an impala. My dad had an 07 LTZ and, while it was durable, the cheap interior, road noise, blind spots, drive by wire, and general impala-ness made me grow to love the Grand Prix more.

**Fivefingerdeathpunch** · 10-20-2015

Did you mean 30 and not 40?

No way you'd ever see 40 in a 3800 with that many revs, but the DIC likes to lie sometimes. And the speed becomes the enemy aswell, it could have a lower rpm but it will be under load more trying to stay at those speed with the wind/terrain. Crank the speed down and you'd see better results.

**BillBoost37** · 10-20-2015

I'd like to say...before Tyler logs in.. how awesome A2W IC's are... because even Audi uses them.

**matt270avian** · 10-20-2015

Regardless of what you decide to do, if you do it you better thoroughly document it in a single thread. No more of this multiple thread with barely any sources, pictures, or information BS.

**16MustangVet** · 10-21-2015

Garbage ic needed to make 300 hp lololololol silly vag junk but hey at least you got that 6 speed....... I guess your 1 for 2 on the wins.....

**Turbocharged400sbc** · 10-21-2015

with the overall OD fdr being nearly the same, splitting the OD would only help around 40mph duri ng light driving

gm designed the v6 to have excellent low/mid range tq, so it would help but not in any major way.

youd do more to do all the flow mods and then flash to a no PE bin and just lean burn it

**00Daytona** · 10-22-2015

Originally Posted by Fivefingerdeathpunch

Did you mean 30 and not 40?

No way you'd ever see 40 in a 3800 with that many revs, but the DIC likes to lie sometimes. And the speed becomes the enemy aswell, it could have a lower rpm but it will be under load more trying to stay at those speed with the wind/terrain. Crank the speed down and you'd see better results.

No, it was saying 40-42. keep in mind this was right after I had done all new wheel bearings, control arms, struts, springs, spot on alignment driving straight as an arrow. realistically it was probably closer to 35mpg.

**Fivefingerdeathpunch** · 10-22-2015

And going downhill.

Not that it matters, real world mpg at 80 on avg is sub 30 mpg.

**MrPoopyButthole** · 10-22-2015

It might cheaper to sell the car and buy a car with 6 gears....and/or a manual.

**00Daytona** · 10-22-2015

Originally Posted by Fivefingerdeathpunch

And going downhill.

Not that it matters, real world mpg at 80 on avg is sub 30 mpg.

meh, eitherway. I got the boyfriends jetta to say it was getting 52mpg over a long distance highway commute. Was it actually getting anywhere near 50mpg? hell no. But I drive differently then most people and tend to hyper-mile out of habbit

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