8 Speed does not want to stay in top gear

[BradfordRick]

2016 1500, 6 cyl, 8 speed , the transmission downshifts from top gear with the slightest pressure on the gas, ever so slight uphill grades, passing large truck, even into headwind. I try to travel at about 110km/h. So I am revving a lot higher and using more gas. Been like this since new Dealer says that's the way it is without any codes to check. Any advice? My warranty runs out in August with only 37k so far.

 

[devildodge]

2016 1500, 6 cyl, 8 speed , the transmission downshifts from top gear with the slightest pressure on the gas, ever so slight uphill grades, passing large truck, even into headwind. I try to travel at about 110km/h. So I am revving a lot higher and using more gas. Been like this since new Dealer says that's the way it is without any codes to check. Any advice? My warranty runs out in August with only 37k so far.

It is a V6 gas correct? Working as designed. 8th gear is a second overdrive. Only gonna stay there with tailwind going downhill

 

[Finn5033]

2016 1500, 6 cyl, 8 speed , the transmission downshifts from top gear with the slightest pressure on the gas, ever so slight uphill grades, passing large truck, even into headwind. I try to travel at about 110km/h. So I am revving a lot higher and using more gas. Been like this since new Dealer says that's the way it is without any codes to check. Any advice? My warranty runs out in August with only 37k so far.

This is normal for the pentastar, even fairly normal for the hemi with 3.21 gears. That’s a big truck and the pentastar makes all it’s torque in the high RPM range

 

[Neurobit]

This is normal for the pentastar, even fairly normal for the hemi with 3.21 gears. That’s a big truck and the pentastar makes all it’s torque in the high RPM range

Hmmm. No, not normal on my Hemi with 3.21.
Mine will stay in 8th forever and only down shift when punching it to pass, etc.

 

[Scram1500]

2016 1500, 6 cyl, 8 speed , the transmission downshifts from top gear with the slightest pressure on the gas, ever so slight uphill grades, passing large truck, even into headwind. I try to travel at about 110km/h. So I am revving a lot higher and using more gas. Been like this since new Dealer says that's the way it is without any codes to check. Any advice? My warranty runs out in August with only 37k so far.

The gear ratios in the 8 speed transmission are pretty close together, the revs probably aren't as high as you think. What are the rpms in 7th vs 8th at 110km/h?

 

[JF19Longhorn]

2016 1500, 6 cyl, 8 speed , the transmission downshifts from top gear with the slightest pressure on the gas, ever so slight uphill grades, passing large truck, even into headwind. I try to travel at about 110km/h. So I am revving a lot higher and using more gas. Been like this since new Dealer says that's the way it is without any codes to check. Any advice? My warranty runs out in August with only 37k so far.

You've been driving this truck since new, it's always been doing this, and you are just now thinking it's an issue?

To me it sounds about right for a full size truck and an NA V6 motor. Hell, my previous F150 with the 5.0L V8 4x4 with 3.55s would drop down a gear at the slightest thought of a hill or even a long overpass.

 

[redneck]

yeah my hemi with 3.21 down shift going over bridges on the interstate or if their is a draft coming off the front of a semi truck

 

[Lil'Mike]

Same here - the gas V6 and 3.21 not a great combo. It’s always shifting in and out of 8th on the highway, but loves 8th at 55 and it feels like it wants to stall...

 

[redneck]

not much wind resistance at 55mph thats why it will hold 8th

 

[Billy James]

I think its normal. At 110 kph (68 mph) that Pentastar needs to rev higher to provide enough power to keep your truck at speed; thus shifts down to 7th. A Hemi will have more HP/torque at lower RPM and won't need to downshift to keep you at speed. I had a Wrangler 6 speed with a Pentastar and often had to downshift around 65 to 70 MPH in order to maintain speed, depending on wind, hills, etc. You have a big heavy truck with a little engine that needs to rev to make power.

 

[Finn5033]

Hmmm. No, not normal on my Hemi with 3.21.
Mine will stay in 8th forever and only down shift when punching it to pass, etc.

Well I had a 2019 with Hemi and the 3.21 and it absolutely would down shift while I was cruising if I touched the gas or hit any incline. Seems some other guys on this thread agree with me

 

[bwsRam19]

3.92 ftw