Reply
 
Thread Tools Display Modes
Old 05-19-2019, 01:22 PM   #1
Junior Member
 
Join Date: Dec 2018
Posts: 17
Transmission downshifts on downhill braking

First of all, this problem occurs with TOW HAUL mode OFF

I have a 2019 Forrester on a 2018 E450 chassis. We live in British Columbia so it is just about all mountains. We recently did a trip across the province and ran into lots of long downhill runs usually 8% for over 5Km, some over 10Km..

The problem is that when freewheeling down the start of the slope the transmission wants to downshift every time the brakes are applied, as if it was in tow haul. On an 8% slope you hit 90KPH fairly quickly, so applying he brakes makes it shift down and the RPM jumps to about 3000. The speed starts to build up again so a second application of brakes is requires, the trans shifts down again and you almost hit 4000rpm. Your speed is still about 90kph and if for some reason you need to touch the brakes again, like a corner or a slow truck crawling down the hill, the f---ing trans will shift down again and the thing pegs to over 5000rpm. The only thing to do is to stand on the brakes and bring your speed down to under 40kph and hope no one rear ends you.

On a long 6% slope the terminal velocity of our Forrester 2291SF is about 95KPH, so as long as it is a modern highway it's not a problem but the 8% slopes it's somewhere over 120, so there is no avoiding the transmission trying to blow the engine up.

Has anyone else found this issue with the new Ford 6 speed transmissions. Our last motorhome was a 2006 and did not do this.

Thanks

Mike Stanlake
__________________

Mstanlake is offline   Reply With Quote
Old 05-19-2019, 01:58 PM   #2
Site Team
 
Mr. Dan's Avatar
 
Join Date: Mar 2014
Location: Grayson County, Texas
Posts: 10,990
I think if you study Ford users manuals, you’ll find that to be a feature not a failure. My 2014 GMC gasser 6-speed does it like an exhaust brake to save brakes.
__________________

__________________
SEARCH is your friend!
FR Wildcat 295RSX / GMC Sierra

Nights Camped: '13 = 49/'14 = 74/'15 = 74/'16 = 85/'17 = 110/'18 =111/'19 = 40; booked = 0
Mr. Dan is online now   Reply With Quote
Old 05-19-2019, 02:02 PM   #3
Senior Member
 
NMWildcat's Avatar
 
Join Date: Jun 2012
Location: Southern NM
Posts: 4,435
Seems like most vehicles do this now. Sometimes I let it do it's thing (down shift on brake application), and sometimes I shift manually to avoid that.
__________________
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder
NMWildcat is online now   Reply With Quote
Old 05-19-2019, 02:26 PM   #4
Junior Member
 
Join Date: Dec 2018
Posts: 17
Don’t mind saving brakes but not at the expense of twisting that V10 at 5500rpm for 5 minutes to the bottom of the Salmo-Creston Skyway,
Mstanlake is offline   Reply With Quote
Old 05-19-2019, 02:31 PM   #5
Site Team
 
Mr. Dan's Avatar
 
Join Date: Mar 2014
Location: Grayson County, Texas
Posts: 10,990
Quote:
Originally Posted by Mstanlake View Post
Donít mind saving brakes but not at the expense of twisting that V10 at 5500rpm for 5 minutes to the bottom of the Salmo-Creston Skyway,
Check your manual and see if you can turn the feature off.
__________________
SEARCH is your friend!
FR Wildcat 295RSX / GMC Sierra

Nights Camped: '13 = 49/'14 = 74/'15 = 74/'16 = 85/'17 = 110/'18 =111/'19 = 40; booked = 0
Mr. Dan is online now   Reply With Quote
Old 05-19-2019, 02:38 PM   #6
Senior Member
 
Chuck_S's Avatar
 
Join Date: Aug 2018
Location: Richmond VA
Posts: 702
Perfectly normal and something I appreciate on down grades, especially 8% grades. My 2017 Expedition EcoBoost does this in every day driving. Will not "free wheel" (which is unsafe anyway).

Not sure what computer modules your chassis has. Look in the truck (not RV) forums for what can be altered with Forscan (software) and your laptop.

-- Chuck
Chuck_S is offline   Reply With Quote
Old 05-19-2019, 02:58 PM   #7
Senior Member
 
A32Deuce's Avatar
 
Join Date: Nov 2012
Location: Mount Laurel, New Jersey
Posts: 7,404
Next time manually put it in a lower gear to start down hill, then when you hit the brakes it won't down shift lower. Just did this earlier this month on RT 30 east in Pa. Also had a car trailer attached. 8 mile down hill.
__________________
2012 SunSeeker 3100SS Toad-1962 Futura Average 100 + days camping
A32Deuce is online now   Reply With Quote
Old 05-19-2019, 03:06 PM   #8
Senior Member
 
Join Date: Aug 2016
Posts: 1,171
Quote:
Originally Posted by Mstanlake View Post
the transmission trying to blow the engine up.
You think the engine computer is going to downshift to the point of damage? Bottom line, it's made to scream. Don't sweat it.
aeblank is online now   Reply With Quote
Old 05-20-2019, 01:06 PM   #9
Senior Member
 
Join Date: Apr 2012
Location: South Carolina
Posts: 1,329
Quote:
Originally Posted by Mstanlake View Post
First of all, this problem occurs with TOW HAUL mode OFF


Thanks

Mike Stanlake
Are you sure you have Tow/Haul OFF (dash light is off)? What you are describing is normal for Tow/Haul ON. Downshifting when you touch the brakes with Tow/Haul OFF seems to be wrong. As others have said, check your manual. Maybe Ford changed the programming with your later model compared to how my 2010 E450 Tow/Haul works.
__________________
RamblerGuy
2011 Sunseeker 3100
2016 Ford Edge Toad
RamblerGuy is offline   Reply With Quote
Old 05-20-2019, 02:38 PM   #10
Senior Member
 
BobHanke's Avatar
 
Join Date: Sep 2013
Location: West Des Moines, IA
Posts: 428
Might make sure you are not using cruise control going downhill as that can cause what you are describing.
__________________

__________________
"Lurch" = Georgetown 2011 330TS
Jeep 2016 Cherokee
Pilot = Bob
Navigator = Xiangbing
Crew = NaNa & NiuNiu
BobHanke is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Featured Campgrounds

Reviews provided by


Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 09:04 PM.