Down shifting redline?
Thread Starter
|
New User
Joined: Oct 2005
Posts: 4
Likes: 0
Down shifting redline?
This last weekend I was towing a 9,000lb trailer down a 6% grade with my 05 F350 6.0l. I was in tow haul mode decending the grade at 70mph. I applied the brakes to slow down for a corner when the trans downshifted and shot the RPM's to 3,700. Is this normal?
FTE Leadership Emeritus
Joined: May 2004
Posts: 18,787
Likes: 30
From: Melbourne, Aus
Welcome DoubleUFarm...
Check this thread out if you own a 6.0l
https://www.ford-trucks.com/forums/s...d.php?t=303583
All you ever wanted to know (and then some)
Check this thread out if you own a 6.0l
https://www.ford-trucks.com/forums/s...d.php?t=303583
All you ever wanted to know (and then some)
FTE Leadership Emeritus
Joined: Jan 2003
Posts: 161,999
Likes: 75
From: 3rd Rock
Originally Posted by DoubleUFarm
This last weekend I was towing a 9,000lb trailer down a 6% grade with my 05 F350 6.0l. I was in tow haul mode decending the grade at 70mph. I applied the brakes to slow down for a corner when the trans downshifted and shot the RPM's to 3,700. Is this normal?
...yes breaks 
Last edited by IB Tim; Oct 26, 2005 at 06:49 AM.
Posting Guru
Joined: Oct 2004
Posts: 1,016
Likes: 0
From: Lynden, WA.
6% grade. 3 miles. Loaded truck. About 7,000 lbs for the camp trailer. Decelerating, 4th gear, compression braking. Never went over 62mph with very few taps on the brakes.
Lets see... Thats maintaining about 1,200 less RPM, than with the Torque shift. Not to say that what the TS does is bad. I think it's a great concept. But anything less than getting near redline, decelerating, which is just as damaging as full throttle at the same R's, is more appealing to me.
So, tell me, when using Tow/Haul, will it actually drop two gears at a time? To me that's a massive RPM and reverse torque change on drive train components.
Do most of you relly on Tow/Haul, without the use of brakes?
-Steve
Lets see... Thats maintaining about 1,200 less RPM, than with the Torque shift. Not to say that what the TS does is bad. I think it's a great concept. But anything less than getting near redline, decelerating, which is just as damaging as full throttle at the same R's, is more appealing to me.
So, tell me, when using Tow/Haul, will it actually drop two gears at a time? To me that's a massive RPM and reverse torque change on drive train components.
Do most of you relly on Tow/Haul, without the use of brakes?
-Steve
Thread Starter
|
New User
Joined: Oct 2005
Posts: 4
Likes: 0
I agree! Having the truck downshift to near redline is not desireable. The truck was in 4th holding arount 2750 rpm when I tapped the breaks it down shifted into 3rd. I immediately took it out T/H, almost as a reflex, and was expecting a piston to come through the hood. I hope Ford Engineers know what they are doing!
Former Vendor
Joined: Mar 2004
Posts: 4,362
Likes: 3
From: Hendersonville, NC
They do....
I've wrapped the tach needle around the peg (literally) more than a few times on upshift, and it has never done any bottom end damage or valvetrain damage. IMO it would take well over 6000 rpm to actually force parts to fly. These are very rev-tolerant engines, especially being diesels.
I've wrapped the tach needle around the peg (literally) more than a few times on upshift, and it has never done any bottom end damage or valvetrain damage. IMO it would take well over 6000 rpm to actually force parts to fly. These are very rev-tolerant engines, especially being diesels.
Trending Topics
Cargo Master
Joined: Jun 2003
Posts: 2,203
Likes: 0
From: Carlsbad, California
I tow a 10,000 - 12,000 lb 30' Toy Hauler trailer up and down the grades around Southern California and have also hauled it up/down the continental divide.
Use the T/H mode all the time and never had the tranny downshift into redline on its own or through my tapping of the brake. Generally on anything less than a 6% grade the tranny will hold back the trailer OK without further use of the brakes. On some of the steeper grades I will have to add some additional truck/trailer braking now and then.
Mostly I just have to do the extra braking at the end of a straight section for a turn that is tighter than my current speed, i.e., I'm doing 45 MPH and the tranny is holding back just fine at that speed, but the upcoming turn is advised as 30 MPH, then obviously I need some more brakes.
I'm really happy with the function of the T/H mode.
As far as I can remember from the owner's manual, the redline is 3900 on upshifts though the tranny and engine management will never shift or rev that high in stock trim. The mechanical redline for downshifting and tranny holdback is something like 4300 or 4500 I believe.
Use the T/H mode all the time and never had the tranny downshift into redline on its own or through my tapping of the brake. Generally on anything less than a 6% grade the tranny will hold back the trailer OK without further use of the brakes. On some of the steeper grades I will have to add some additional truck/trailer braking now and then.
Mostly I just have to do the extra braking at the end of a straight section for a turn that is tighter than my current speed, i.e., I'm doing 45 MPH and the tranny is holding back just fine at that speed, but the upcoming turn is advised as 30 MPH, then obviously I need some more brakes.
I'm really happy with the function of the T/H mode.
As far as I can remember from the owner's manual, the redline is 3900 on upshifts though the tranny and engine management will never shift or rev that high in stock trim. The mechanical redline for downshifting and tranny holdback is something like 4300 or 4500 I believe.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Thread
Thread Starter
Forum
Replies
Last Post
kissfan79
Excursion - King of SUVs
20
Feb 20, 2014 11:34 AM
Motorcraftsman
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
4
Apr 10, 2001 11:20 PM