Hard Downshift

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

TrewRaptor

Full Access Member
Joined
Feb 14, 2020
Posts
117
Reaction score
64
Location
Tucson AZ
I looked for experiences with hard shifting but it all seems to be in the lower gears, especially 3-4.
Yesterday I was driving 80ish on the highway and let off on the cruise control to slow down for and exit and there was a loud thud accompanied with a physical bang. Almost like I was shifting from 10th to 2nd gear. It only lasted a second and nothing else happened.
I have a Cobb tune.

Any one experience this?
 

Hdaniel85

Full Access Member
Joined
Dec 21, 2019
Posts
144
Reaction score
111
Location
Southern California
Do you have the TCM Tune as well or just the ECU?

If you have the TCM tune, which one are you running? There are a few canned TCM tunes built into the COBB AP, I have mine custom tuned from Goosetuned.
 

LeadFootLarry

Full Access Member
Joined
Nov 26, 2020
Posts
200
Reaction score
122
Location
USA
I routinely have a harsher downshift from 4-3, typically when braking from higher speeds, rather than coasting down to a stop. Happens even when the truck has been running for a bit and is warm. 2020 with a 2-20 build date
 

isis

FRF Supporting Member
Supporting Member
Joined
Aug 28, 2019
Posts
1,776
Reaction score
1,707
Location
PA
I have a 2017 and 3-4 are always the harshest.
 
OP
OP
TrewRaptor

TrewRaptor

Full Access Member
Joined
Feb 14, 2020
Posts
117
Reaction score
64
Location
Tucson AZ
I do have the Cobb TCM Tune. this was a one off situation so I thought I 'd check with the group. It's currently a stage 1 91 octane.
 

wkasak_17Raptor

Active Member
Joined
Jan 9, 2019
Posts
60
Reaction score
58
Location
Elkridge, Maryland
I also have the periodic 4-3 downshift that sounds and feels like the rear differential just grenaded. Like old school bad u-joints type hammering because of slack in the driveline. I have had the trans re-flashed by the dealer and it seems to help for a period of time then returns. So annoying for such an expensive truck when I need to explain what it was to family and friends and I can't.
 

03'Darin

FRF Addict
Joined
Sep 9, 2016
Posts
1,056
Reaction score
783
Location
Harrisburg Pa
I have similar issues with the shifting. Which would slowly get worse. I have an MPT tune and discovered if I change tunes (which resets the transmissions adaptive learning) the shifting issue goes away. So I'll switch to a different tune and then switch right back. It slowly comes back over time though. So every maybe 6-8k miles I do the tune swapping.
 
Joined
Aug 20, 2020
Posts
46
Reaction score
64
Location
Redwood City, CA
I had this issue on mine, super hard shift from 10th to 5th on the highway after a sustained long climb in 9-10th and then all of a sudden I noticed a hesitation in the shifting and then it slammed into 5th. Its been to the dealer 4 times now, they can never get it to do the same thing (I really only does it on the long mountain pass climbs) and they have no idea how to solve it. I did add a Cobb with goose tuned and the shifting has been SO MUCH better than stock and I hope next time im driving up the mountains I don't have that issue again
 
OP
OP
TrewRaptor

TrewRaptor

Full Access Member
Joined
Feb 14, 2020
Posts
117
Reaction score
64
Location
Tucson AZ
I had this issue on mine, super hard shift from 10th to 5th on the highway after a sustained long climb in 9-10th and then all of a sudden I noticed a hesitation in the shifting and then it slammed into 5th. Its been to the dealer 4 times now, they can never get it to do the same thing (I really only does it on the long mountain pass climbs) and they have no idea how to solve it. I did add a Cobb with goose tuned and the shifting has been SO MUCH better than stock and I hope next time im driving up the mountains I don't have that issue again

Thats exactly what I experienced. Sounds like a goose tune after the FMIC is installed.
 
Top