6 Speed Tans shift points

nick_si · Aug 19, 2013

6 Speed Transmission shift points

I have a question reguarding shifting at certain speeds. When I am driving 60mpg my rpms are about 1500-1600 in 6th gear. Running 3.21's. Also running 35's.
When I try to downshift from 6th into 5th the truck does not downshift. When I go from 5th to 4th it will downshift. It seems to me it is not shifting into 6th? Does anyone elses truck do this?

emjohn4 · Aug 19, 2013

I doubt you're really in 6th gear at 60mph.

FWIW - my '12 with stock tires and 3.92's doesn't shift into 6th until about 60.

Try it again at 70mph, and see if it shifts from 6th to 5th.

Ramunit · Aug 19, 2013

At 60 mph with 35" tires with 3.21s your rpms in 5th (.75 trans ratio) calculates to 1380 rpms. The correlation between the downshift and the corresponding upshift in these transmissions is horrible, It's all in the way the program it from the factory. The reason I know this is because on my 05 I have the ability to tune my transmission and review the stock shift schedule, I'm lucky I can adjust out my downshift lag but you guys with the 13s will have to wait until tuning is available.

nick_si · Sep 5, 2013

Thanks for the input guys.

Since the truck was sold to be brand new with everything already installed and under warranty from the dealer they should correct this issue at no cost to me.
The service writer told be they can only adjust up to a 33" tire, if that is true or not I do not know.
Worst case I can have them purchase an aftermarket tuner to fix the spedo and shift points if they will go for that.

6 Speed Tans shift points

nick_si

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emjohn4

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Ramunit

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nick_si

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